Chapter 12:

This is Chapter 12 from R. C. Schafer, DC, PhD, FICC's best-selling book:
Symptomatology and Differential Diagnosis

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Basic Examination Procedures 



Low Back Pain 


Trauma: Lumbar and Sacral Syndromes 

Chapter 12: The Lumbar and Sacral Areas


The most common symptom of the lumbar and sacral areas, by far, is pain. In fact, back pain is one of the most prevalent symptoms in America today, second only to headache. Its causes may be direct or referred and be the result of dysfunction or disease, either focal or general in nature.

The multiplicity of causative and effected ailments is almost endless. At times, the cause is readily apparent. At other times, it is a frustrating determination because of the spinal column's complex structure, weight-bearing chores, and close relationship with the nervous system and cerebrospinal circulation. The confusion can only be relieved through knowledge of the structure, function, and pathophysiology of the body that is producing the symptoms and signs, and an intelligent interpretation of all findings.

Functional Considerations

As in the thoracic spine, the movements of the lumbar spine are flexion, extension, lateral bending, and rotation. Lateral flexion is relatively free in the lumbar region, followed in order of mobility by extension, flexion, and rotation (minimal). The range of lumbar motion is determined by the disc's resistance to distortion, its thickness (Table 12.1), and the angle and size of the articular surfaces. Most significant to movements in the lumbar spine is the fact that all movements are to some degree three dimensional; ie, when the lumbar spine bends laterally, it tends to also rotate posteriorly on the side of convexity and assume a hyperlordotic tendency.

     Table 12.1. Intervertebral Disc Regional Variables

DiscsAverage ThicknessDisc:Body RatioNucleus:Anulus RatioPosition to Vertical Axis
3 mm
4:7 57% nucleus
Centered Posterior
5 mm
3:7 43% nucleus
9 mm
4:6 67% nucleus
Centered Posterior


Extension is primarily the product of bilateral action of the thoracic and lumbar erector spinae, semispinalis, with some assistance provided by the deep posterior spinal muscles. Extension is controlled by stretching of the anterior longitudinal ligament and rectus abdominis, relaxation of the posterior ligaments, and contraction of the spinal extensor muscles.

Loss of lumbar extension is usually the result of poor sitting posture and/or inadequate extension mobilization following injury in which shortened scar tissue prevents a full range of extension. Reduced extension:

(1) causes chronic stress on the soft tissues of the posterior motion unit and an increased intradisc pressure during sitting;
(2) restricts a fully upright posture during relaxed standing, leading to a stooped appearance in stance and gait; and
(3) produces a premature fully stretched lumbar posture when arising from a forward flexed posture.

If posterior disc protrusion, facet inflammation, or spondylolisthesis exist, pain will be increased during extension. If a person must work habitually in a prolonged forward flexed position, periodic lumbar extension will relieve the stress of the posterior anulus and tend to shift a loose nucleus pulposus anteriorly; ie, away from the spinal cord and IVF. Many manual workers do this maneuver automatically.


Flexion is the most pronounced spinal motion. About 75% of all spinal flexion below the neck occurs in the lumbar spine, and about 70% of all lumbar flexion occurs at the lumbosacral joint.

Any muscle with vertical or oblique fibers that connects the thorax with the pelvis assists in flexion of the trunk. The major actions involved are bilateral activity of the rectus abdominis, external and internal oblique, and psoas major.

During lower back flexion or extension, there is far less vertebral gliding than seen in other areas of the spine during A-P motion. Widening of the anterior disc on extension or of the posterior disc on flexion does not occur until movement nears its full range of motion. Even then, it is much less than that seen in other areas of the spine. The anterior longitudinal ligaments relax during lumbar flexion, and the supraspinal and interspinal ligaments stretch.

To measure flexion, the standing patient flexes forward and attempts to touch the floor with his fingertips. Then the floor-fingertip distance is measured. Such flexion in the adult will not normally result in a kyphosis of the lumbar area as flexion does in the cervical area. While a number of disorders result in decreased flexion, paraspinal muscle spasm is the primary cause.


In evaluating lateral flexion of the lumbar spine, the standing or seated patient's iliac crest should be stabilized as he leans to the opposite side as far as possible. All trunk flexors and extensors can produce lateral flexion when acting unilaterally. The major muscles involved are the rectus abdominis, external and internal obliques, erector spinae, semispinalis thoracis, latissimus dorsi, deep posterior spinal muscles, quadratus lumborum, and psoas.


Thoracolumbar rotation to the opposite side is produced essentially by unilateral action of the external oblique, semispinalis, and the deep posterior spinal muscles. Rotation to the same side is produced by the internal oblique and erector spinae. See Table 12.2. While lumbar motion is potentially greater than that of the thoracic spine because of the lack of rib restriction, the angle of facet facing and the heavy ligaments check the range of rotary motion.

Although great curves in the lumbar area are commonly seen, most of the apparent rotation seen is from distortion of the lumbar spine's base, tipping, and the lumbar lordosis viewed out of its normal plane.

     Table 12.2. Trunk Motion

Joint MotionPrime Movers and Accessories
ExtensionIliocostalis lumborum
Iliocostalis thoracis
Longissimus thoracis
Quadratus lumborum*
Spinalis thoracis
Flexion with rotationExternal oblique
Internal oblique abdominis
Forward flexionExternal oblique abdominis*
Internal oblique abdominis*
Psoas major*
Rectus abdominis
Lateral flexionErector spinae group
External oblique abdominis
Internal oblique abdominis
Latissimus dorsi
Psoas major
Quadratus lumborum
Rectus abdominis
Semispinalis thoracis
Transversospinalis group
RotationErector spinae
External oblique abdominis
Internal oblique abdominis
Psoas major*
Quadratus lumborum*



Because of the restriction of normal movements in the thoracic spine and the relatively mobile lumbar spine below, the intervening thoracolumbar area must achieve a degree of hypermobility in all three body planes. Thus, as is true to some extent in all spinal transitional areas, the thoracolumbar junction is more prone to stress from both above and below because of its unusual design.

The articulating facets of the transitional vertebra resemble thoracic facets and are designed for rotation and lateral flexion, even though these motions are restricted somewhat by the free ribs. While the stiff thoracic spine tends to move as a whole, most rotation takes place in the lower segments that are not restricted by the rib cage.


The junction of L5S1 resembles a "universal joint." For example, when the sacrum rotates anteroinferior on one side within the ilia, L5 tends to rotate in the opposite direction because of the restraint of the iliolumbar ligament. The effect is a mechanical accommodation of the lumbar spine above assuming a posterior rotation on the side of the unilateral sacral anteroinferiority. It also tends to assume an anteroflexed position, thus producing the three-dimensional movements of the lumbar spine. In view of the intricacy of the lumbosacral junction, anomalies (eg, asymmetrical facets) have a strong influence on predictable movements in this area.

Because of its deep position below the iliac crests and the strong strapping by the iliolumbar ligaments and spinal extensors, L5 is only as movable as the sacral base will allow. Thus, when lipping of or spurs at the inferior L5 body are seen, a history of instability can be presumed.


Slight but smooth movement is permitted upward, downward, forward, and backward within the sacroiliac articulations, and axial rotation occurs around a transverse axis to allow pelvic tilting. Because the sacrum does not have distinct articular planes but moves within the pelvic ring, its motion is multidirectional for 13 mm rather than in restricted directions. This multidirectional motion is especially passive in the non-weight-bearing positions and affected above from lumbar forces and/or laterally and below from iliac-ischial forces.

Neurologic Considerations

The nerve roots are not normally fixed to the margins of the IVFs, according to some authorities. However, Wyke and others report that they are. We can suspect that fibrotic changes following the granulation tissue of irritation, especially in the lumbosacral region, frequently fix the sleeve at one or more points. This would contribute to traction on the sheath and its contents during movements such as exhibited in a supine straight-leg-raising test. Such abnormal attachments increase in strength with repetitive trauma, aging, and other degenerative changes.


The segmental innervation of the lumbosacral spine to the associated major musculature and the related skin and tendon reflexes are shown in Table 12.3. The major nerves of the lumbosacral plexus and their function are given in Table 12.4.

There are about twice as many sensory fibers than motor fibers in the lumbar roots. When the anterior root is irritated, pain is felt in the muscles supplied and often becomes self-perpetuating from the focal spasm produced. In posterior root irritation, pain can be felt in the dermatome, myotome, sclerotome, and possibly in the viscerotome.

The nerve root in the lumbar spine runs anterior and superior to the facets. It is often compressed in the IVF by a subluxated articular facet and less often by a herniated disc or a spur from the posterior aspect of the vertebral body. These disorders can be made worse by spinal stenosis, which narrows the vertebral canal and possibly the tunnels in which the nerve roots exit.

     Table 12.3. Segmental Innervation of the Lumbosacral Spine

SegmentMajor Muscles Supplied
L2-3Sartorius, pectineus, abductor longus
L2-4Quadriceps, gracilis, adductor brevis
L3-4Obturator externus, adductor magnus and minimus
L4-5Tibialis anticus
L4-S1Semimembranosus, semitendinosus, extensor hallucis longus, popliteus, plantaris, extensor digitorum longus, extensor hallucis brevis, gluteus medius and minimus, quadratus
L5-S1Peroneus longus and brevis, tibialis posticus, flexor digiti brevis, abductor hallucis
L5-S2Gluteus maximus, obturator internus, biceps femoris, soleus, gastrocnemius, flexor hallucis longus
S1-2Lumbricales, piriformis, abductor digiti, flexor digiti, opponens, quadratus plantae, interossei
S2-4Levator ani, bulbocavernosus, ischiocavernosus
S4-5Sphincter vesicae
S5-Cx1Sphincter ani, coccygeus
SegmentTendon Reflexes

     Table 12.4. Nerve Function of the Lumbosacral Plexus

FemoralSensory to skin over anterior and medial thigh, knee, leg, dorsum of foot to base of 1st metatarsal. Motor to iliacus, pectineus, sartorius, quadriceps femoris.
GenitofemoralSensory to skin over scrotum, upper anterior thigh area. Motor to the cremaster.
IliohypogastricSensory to skin over hypogastric and lateral gluteal areas.
IlioinguinalSensory to skin over genitalia and upper medial thigh area.
Inferior glutealMotor to gluteus maximus.
Lateral femoral cutaneousSensory to skin over lateral thigh.
Muscular branchesMotor to major and minor psoas, quadratus femoris, gemellus inferior and superior, piriformis, obturator internus.
ObturatorMotor to adductor longus, brevis, magnus; obturator externis; gracilis.
Posterior femoral cutaneousSensory to skin over inferior buttock, posterior thigh, popliteal space, perineum, external genitalia.
PudendalSensory to skin of genitalia, anus, scrotum, labium majus, penis, clitoris. Motor to levator ani, coccygeus, sphincter ani externus, transversus perinei superficialis, profundus, bulbocavernosus, ischiocavernosus, sphincter urethrae membranacae.
SciaticSensory to skin over posterolateral aspect of leg and lateral foot; heel; over upper third of lateral aspect of leg below knee; over anterolateral aspect of leg and dorsum of foot and toes; medial aspect of sole, great toe, 2nd to 4th toes; lateral aspect of sole, 4th and 5th toes; on dorsum of foot between great toe and 2nd toe.

Motor to hamstrings, adductor magnus, gastrocnemius, plantaris, soleus, popliteus, tibialis anterior and posterior, flexor and extensor digitorum longus and brevis; peroneus longus, brevis, and tertius; abductor and adductor hallucis, flexor hallucis brevis, extensor hallucis longus, quadratus plantae, abductor digiti quinti brevis, all interossei, and 1st through 4th lumbricals.
Superior glutealMotor to gluteus minimus and medius, tensor fascia lata.


Anal Reflex.     Normal contraction of the sphincter on light stimulation of the anal skin is referred to as the anal reflex. This reflex is also initiated when a gloved finger is inserted into the rectum such as during a prostate examination. This normal reflex is absent in tabes dorsalis and lesions of the cauda equina or conus medullaris.

Bladder and Rectal Reflexes.     These reflexes are often important diagnostic signs. Normal sphincter regulation of the bladder and rectum is under the control of the pelvic autonomic nerves. If the motor fibers to these sphincters are impaired, incontinency is the result. If the sensory fibers are impaired, distention and dribbling result because the urge to defecate or urinate has been diminished (eg, tabes dorsalis).

Dire fear or an equal emotional state or cord severance results in a mass emptying of the bladder and bowels, flexion of the lower limbs, and profuse sweating. This syndrome (mass reflex of Riddoch) is normal in most infants until voluntary control is learned and directed by the higher centers. In cord severance, the syndrome may be initiated by nothing more than scratching the foot.

Cremasteric Reflex.   The cremasteric reflex exhibits the integrity of the L2 nerve. It is especially active in young men when the superomedial aspect of the thigh is stroked. The contraction of the cremasteric muscle of the same side that causes the testicle to be drawn upward should be observed. An absent or diminished response indicates a lesion of the corticospinal tract or a lesion of the femoral or genitofemoral nerves.

Remark's Sign.     This sign results when for any reason the conducting pathways of the cord are interrupted. When the upper third of the anterior surface of the thigh is mildly stimulated by stroking, the reflex consists of extension of the knee with plantar flexion of the first three toes in which the foot may also participate by full plantar flexion.

Viscerosomatic Reflexes.     The sacral parasympathetics as well as the thoracolumbar sympathetics innervating the viscera are accompanied by a meager but sufficient quantity of viscerosensory fibers. These afferent fibers have extensions into the dorsal horns of the cord at the same level and from three to four segments above and below. Any visceral disturbance will therefore register itself upon the synaptic fields of the dorsal horns and in turn provide impulse bombardment via internuncial neurons to the ventral horns. This results in a reflex contraction of the muscles supplied. In this context, Janse feels that the muscles most directly affected by this noxious reflex from an irritated viscus are the multifidi, rotatores, intertransversarii, and psoas major muscles.

Local contraction of these muscles, usually unilateral, may prevent one or more vertebra from participating in normal scoliotic compensations or the segment(s) may be pulled into an exaggerated displacement (subluxation), depending on which side of a scoliotic curve the unilateral contraction occurs. Thus, once a site of incompatible deviation or fixation is found, it is a great aid in the diagnosis of segmentally related visceral complaints.

      Structural Considerations

Static postural support of the lumbar spine in the prolonged relaxed erect or seated postures is provided essentially by the passive elastic tension of the involved ligaments and fascia rather than the spinal muscles whose roles can be considered insignificant during a state of relaxation. This shifting of support from muscles to the ligaments, however, occurs slowly over a period of several minutes before significant EMG activity can be considered absent.

The thicker anterior aspect and thinner posterior aspect of the lumbar discs provide the lumbar spine with its unique rotation, lateral bending, or combined phenomena. The coupled lateral bending and rotation of the lumbar spine during forward flexion:

(1) protects the axial length of the lumbar spine and its contents from excessive tension; and
(2) causes the peripheral fibers of the annulus to draw inward, thus securing the nucleus more firmly as a protection against displacement.

This helps to further explain why fixation inhibiting rotation during flexion invites IVD protrusion. If rotation is not freely allowed during flexion, the segment tends to slide laterally and produce excessive shear forces upon the subjacent IVD and posterior facets. These basic characteristics of the lumbar spine coupled with the mechanics of the ilia are the major factors that govern sacral dynamics.

Elderly patients may lose considerable height as compared to their height in early maturity due to thickening of the ligaments, weakening of the musculature, and thinning of the IVDs. The range of motion of the spine is, of course, also considerably less.


In general, faults in weight bearing can be attributed to the anterior portion of the vertebral motion unit, while faults in the direction of distortions can be blamed on the posterior aspect of the motion unit.

Body weight is carried in the lower back essentially by the L5 disc and dissipated to the sacral base, sacroiliac joints, and acetabulae. This weight on the L5 disc is forced slightly anterior on the load surfaces. The lateral line of gravity cuts a point just anteroinferior to S2. Weight distribution in the lumbar region is governed chiefly by the inclination of each vertebral body articulation. The lateral center line of gravity falls upon the spinal points because of gradual changes in the angles of the inclined planes of the various articular surfaces. This tends to force each lumbar vertebra more inferior, medial, and anterior or posterior until gravity brings the apex of the curve back toward the balancing point.


All vertebrae move in the planes of their articulations, and it is at the posterior intervertebral articulations that most subluxations occur and influence the IVFs. Changes in the diameter of normal IVFs result in an abnormal joint formation that predisposes further subluxation and begins altering the curves of the particular region of the spine that this structural defect is found.

Contents.     Each foramen widens and expands with spinal motion. From one-third to one-half the foraminal opening is occupied by the spinal nerve root and its sheath, with the remaining portion filled essentially by fat, connective tissue, and various vessels. The IVF contains the anterior nerve root, the posterior nerve root, a part of the dorsal nerve root ganglion, a bilaminar sleeve of dura and arachnoid membrane to the ganglion, a short continuation of the subarachnoid space with cerebrospinal fluid which ends just after the ganglion, the recurrent meningeal nerve, the spinal ramus artery, the intervertebral vein, and lymphatic vessels.

Shape and Size.     Lumbar IVFs are shaped laterally like inverted teardrops or kidney beans, with the diameter of the vertical axes about double the A-P dimensions. There is normally adequate space for changes in vertical dimension during normal movements without injury to the IVF contents as long as there is adequate fat and fluid present and stenosis and adhesions are absent. However, reduction of the already short transverse diameter can produce a number of ill effects. For this reason, disc collapse anteriorly is often asymptomatic, while a slight posterolateral bulge may protrude upon the IVF and produce severe symptoms.

Diameter Changes.     The common factors altering the diameters of the IVFs are the disrelation of facet subluxation; the changes in the normal static curves of the spine; the presence of induced abnormal curves of the spine; degenerative thinning, bulging, or extrusion of the related IVD; swelling and sclerosing of the capsular ligaments and the interbody articulation; and marginal proliferations of the vertebral bodies and articulations.

These factors altering the IVF diameter insult the viable contents of the IVF. The result is nerve root pressure, traction, or torque; constriction of the spinal blood vessels; intraforaminal and paraforaminal edema; induration and sclerosing of the periarticular ligaments with trauma to the receptors; and forcing of the foraminal contents into protracted constriction and altered position. Acute phenomena are usually the result of friction, severe or repeated trauma, and encroachment from degenerative thickening or exostosis, rather than of neurologic origin.

     Basic Examination Procedures

When fatigue accumulates after prolonged physical activity, the poorly conditioned individual will experience aching, stiffness, and soreness in overly exerted muscles. This is common in the lower back muscles. If at least rest, warmth, or stretching exercises are not offered, chronic strain can lead to the typical posture of spinal "sag," exhibiting drooping shoulders, a rounded thoracic region, inhibited rib and diaphragm motion, shallow breathing, lumbar hyperlordosis, anterior longitudinal ligament stretching, anterior pelvic rotation, chronic apophyseal synovitis, backache, disc collapse, bulging abdomen, visceroptosis, digestive disturbances, flatulence, and chronic tiredness.

A comprehensive postural evaluation of the lumbar and sacral areas should include a comparative analysis of the physical signs of the full spine as found in the standing, sitting, Adams, prone, and supine positions, both with and without the use of a plumb line, grid, or other instrumentation. This multiposition visual and palpatory examination is one of the first steps in physical spinal analysis. However, in no way should it preclude the use of necessary instrumentation, laboratory procedures, or roentgenography.

The Standing Position

The patient should be instructed to stand relaxed, with the heels together and the hands hanging normally at the sides. The primary points of reference in visual analysis are trochanter level (marked); sacral level; iliac crest level; direction of pelvic rotation; direction of lumbar, thoracic, and cervical scoliosis; shoulder girdle level and its direction of rotation; and occipital tilt.


Overall curvatures of the spine should be noted and evaluated as normal, lordotic, kyphotic, or scoliotic. The most common standing postural fault associated with low back pain is not hyperlordosis; it is an abnormal flattening of the lumbar area. Frequently associated is a lateral shift (scoliosis) away from the midline.

Although the lumbar spine falls into full flexion during relaxed or prolonged sitting, prolonged standing in a relaxed posture places the lower lumbar spine into full extension. Thus, if symptoms are aggravated by prolonged standing, it is evident that sustained lumbosacral extension is causing a mechanical deformation. If symptoms are relieved by prolonged standing, an important diagnostic clue is gained that will direct therapy to obtaining sustained extension.


Body balance is most efficient in the standing position when the vertical line of gravity falls through an aligned column of supporting bones. If the segments are aligned so that the gravity line passes directly through the center of each joint, the least stress is placed upon the adjacent ligaments and muscles. This ideal situation is impossible in the human body because the centers of segmental links and the movement centers between them cannot be brought to accurately meet with a common line of gravity.

Plumb line analysis should be conducted from the front, back, and bilaterally:

Anterior.   From the front, a plumb line should cut between the eyes, through the nose and neck, through the sternum, xiphoid process, navel, pubic symphysis, and bisect the knees and ankles. The horizontal level of the ears, shoulders, nipples, rib angles, iliac crests, hips, patellae, and maleoli should be noted.

Posterior.   From the back, the line should cut through the occipital protuberance, spinous processes, gluteal crease, and coccyx, and then bisect the knees and ankles. The horizontal level of the ears, shoulders, scapula, rib angles, iliac crests, greater trochanters, knee joints, and maleoli should be noted.

Lateral.   From each side, the line should cut through the ear lobe slightly posterior to the mastoid process, odontoid, tip of the shoulder, anterior edges of T2 and T12, centrum of L3 just anterior to S2, just posterior to the axis of the hip, posterior to the patella, anterior to the lateral malleolus of the ankle, and then through the cuboid-calcaneal junction and the 5th metatarsal of the foot.


Abnormal rotation or tilt of the patient's head should be noted, and the cervical and suboccipital muscles should be palpated. Asymmetrical fullness of the suboccipital musculature usually indicates upper cervical rotation.

The comparative height of the scapulae should be observed, and the contours of the area muscles should be palpated to seek signs of abnormal tightness or tenderness. The cervicobrachial spine is always scoliotic toward the side of the high shoulder. Winged scapulae or blades failing to lie smoothly upon the chest wall should be sought.

The midthoracic spine is always scoliotic toward the side that the vertebral margin of the scapula is more prominent and flaring. If the shoulder is high on the right and the scapula flares on the right, the entire cervicobrachial and thoracic spine is scoliotic toward the right. If the shoulder is high on the right yet the left scapula flares, it indicates that the cervicobrachial spine is scoliotic to the right and the midthoracic spine is scoliotic to the left.


The angles of the ribs should be noted. In pelvic mechanical pathologies on the side of involvement, there is a reduction in the height and depth of the body angle as observed from the A-P. A difference in the height of the scapula and the iliac crests usually indicates a scoliosis.


The comparative height of the iliac crests should be noted. A low and less prominent iliac crest will be best observed from the front. If chronic sciatic neuralgia is on the high iliac crest side, degenerative disc weakening with posterolateral protrusion should be suspected. If it occurs on the side of the low iliac crest, the possibility of a sacroiliac slip and lumbosacral torsion should be considered as a likely cause.

The position of the gluteal cleft should be noted. An imaginary line passed through the crease of the buttocks should demonstrate its lower aspect equally between the feet and its upper aspect over the C7 spinous process and the occipital protuberance. Tension of the gluteals and the comparative height and depth of the sacral dimples should also be noted.


The standing patient is asked to flex sideward and move his hand on the side of bending distally down the side of his thigh as far as possible. This point should be recorded. Lateral flexion should occur from above downward. The examiner's fingertips should be placed in the lumbar interspinous spaces to evaluate segmental motion. The maximum range of motion and the production, increase, or reduction of pain and its distribution should also be evaluated. It is not unusual to find that one side is unrestricted and the other side is blocked. This suggests a degree of scoliosis, with restricted movement on the side of convexity. A contralateral segmental fixation or a laterally displaced nucleus pulposus would have the same effect. Before concluding this part of the examination, the examiner should test the effects of repetitive side bending


The transverse processes of the lumbar vertebrae should be palpated. Lateral positions of the spinous processes and anterior or posterior positions of the transverse processes together with an elevation of the angles of the ribs would indicate a rotation of vertebrae. The possibility of a spinous process being asymmetrical, deviated to the right or left, without the body of the vertebra being involved should always be kept in mind.

The Adams Position

The patient assumes the Adams position by standing erect, with his heels together, then bending forward with his fingers as near the floor as possible without straining. For an indication of gross spinal flexibility, the distance between the fingertips and the floor should be measured or at least observed. In bending, the knees should not flex. As a patient advances in age and the spine settles, there will of course be less flexibility. Stiffness would also occur with hypertonic or spastic paravertebral muscles.

While the patient goes in and out of the flexed Adams position, the following points should be noted:

(1) Is flexion unrestricted?
(2) Is flexion straight forward or deviated laterally?
(3) Do the spinous processes line up straight during forward flexion and extension from flexion? This is more easily determined by dotting the spinous processes with a skin pencil when the patient is in the standing position.
(4) Are there abnormal prominences or movements of the angles of the ribs during A-P motion? Is the pelvis level?

The two most common clinical signs that appear are:

(1) restriction of end motion (motion block, with or without pain) in which the patient's fingers stop far above the floor, and/or
(2) scoliotic rotation of the spine in which the vertebral bodies follow the plane of least resistance (structural or antalgic scoliosis).


During the first stage of flexion, the normal lumbar lordosis gradually flattens and then gradually develops a smooth curved kyphosis. In many people, the degree of lumbar flexion is up to and only slightly over the flattening of the normal lordosis, thus total possible flexion must be achieved by hip rotation. In fact, some people can bend forward to touch the floor with little change in the spinal curves. This is often due to hypermobile ilia and hips adapting to lumbar fixation.

If the lumbar curve fails to flatten during trunk flexion, the first suspicions should be restriction of the posterior elements from muscular hypertonicity, ligamentous shortening, or abnormal articular planes. Unilateral facet asymmetries will often be revealed by a distinct scoliosis exhibited in the Adams position that is not apparent at all in the erect position. If pelvic rotation fails to occur, the first suspicions should be sciatic irritation, hip restriction, or tight hamstrings. If a hamstring fails to elongate unilaterally, distinct contralateral lumbar rotation will be seen during flexion as L5 follows the low sacrum.


The Adams maneuver is possibly the best to detect unusual vertebral rotation and ascertain the integrity of lumbosacropelvic rhythm. This latter point is an excellent method of gathering accurate clues of biomechanical faults.

Forward flexion takes place in two phases. During the first 60 of flexion, the pelvis is locked by the posterior pelvic muscles. About 70% of this motion occurs at the lumbosacral joint, 20% between L5L4, and 10% between the L1 and L3 vertebrae. The motion is smoothed by the counterforce of the spinal extensors. During the second phase, from 60 to 85, the hip releases and the pelvis rotates bilaterally forward around the transverse axis of the hip joints. Near the end of spinal flexion, the sacral base slightly follows L5 anteroinferior as the sacral apex pivots posterosuperior.

Perfect synchronization of these lumbar-sacral-pelvic motions must be achieved to obtain minimal biomechanical stress. Abnormalities in these mechanisms will quickly point out and help differentiate sites of lumbar, sacral, or hip restrictions or instability.


As the patient goes into and out of the Adams position, the vertebral column should be examined for individual segments that flatten or arch at the wrong time or do not move evenly with their neighbors. Palpation should be done with the fingerpads upon the interspinous spaces. With motion, the various segments of the spine can be felt to glide closer together or further apart. Should an area be found that remains rather immobile or without the normal gliding action, further tests and x-ray studies should be made of that section of the spine.

When one or more spinous processes are out of alignment, spinal lesions, subluxations, or an abnormality of the spinous process are indicated. Frequently, two or more spinous processes that are out of alignment will indicate multiple subluxations in portions of the vertebral column, perhaps with the exception of the middle thoracic column. But even these may sometimes be involved.


In common pelvic mechanical pathologies on the side of involvement, there is an observable slanting and anteriority of the pelvis in the forward bending position. There will be a noticeable lumbar scoliosis to the side of involvement.

Several biomechanical influences are expressed in idiopathic scoliosis when viewed in the Adams position. They can be best appreciated by test movements that place normal stress on normal or abnormal tissues. The most common factors involved are:

1.   A rotational subluxation, causing the superior segment to follow the plane of its base.

2.   An area of acute or subacute inflammation (eg, myositis, strain, sprain), causing deviation away from the site of pain.

3.   An anatomic or functional short leg, causing the lumbar spine to follow the tipped base of the sacrum.

4.   A laterally displaced end plate or nucleus pulposus, causing flexion away from the painful side.

5.   The presence of a fixed nerve root (eg, mechanically entrapped or locked by adhesions), causing lateral deviation during forward flexion toward the side of binding. Forward flexion in the standing position places considerable stretch on the sciatic nerve.

6.   Bilateral or unilateral fixation of a posterior motion unit, causing restricted forward flexion.

7.   Asymmetrical facets or facets facing in an unusual plane.

8.   The presence of scar tissue from repeated attacks of disc or facet injury, causing restricted forward flexion and a slight swing toward the side of abnormal stiffness.


Repetitive loading has beneficial effects on shortened tissues and adverse effects on the disc or an area of inflammation (eg, sciatic neuritis). To test the effects of repetitive lumbar flexion loading, the standing patient is asked to flex forward to the maximum and return to normal ten times in succession. If the patient's pain increases, a disc involvement or area of inflammation is probably the factor involved. If the patient's pain reduces, shortened tissues are most likely the origin of the patient's pain.


Where the spine does not bend straight forward during the Adams position but deviates to one side, even slightly, a search should be instituted for contractured, thickened, or shortened muscles, tendons, and/or ligaments of the column existing on one side and not on the other. If the spine shows rotation to the right, for example, the patient in a forward bent position can swing his torso into right rotation much more readily than to the left.

Elevation or prominence of the ribs on either side denotes a rotation of the vertebrae upon their axes. Shortening of the ligaments with contracture of the musculature of the spine will be exhibited by abnormal stiffness or hardness of the muscles on the side of the spine that suffers from contractures.


Just as much information can be gathered as the patient returns to the neutral position as during flexion. If a load is being lifted, the vast majority of the force is upon the posterior lumbar ligaments until about 60 when the back muscles become active and the abdominals serve to smooth the action. The main function of the longitudinal ligaments is to restrict abnormal motion. If there is segmental restriction, excessive motion is forced upon the adjacent segments and the hips. Hip restriction forces excessive motion upon the lumbar spine and sacrum. If there is excessive joint laxity, subluxation with or without sprain or strain may occur.

The most common fault recognized in extension from full flexion is premature return of the lumbar lordosis. If this occurs, the first suspicion should be weak hamstrings and/or other pelvic extensors. Associated weak abdominals will contribute to faulty pelvic stabilization.


Forward bending puts the lumbar spine in hyperflexion, and overhead work puts the lumbar spine into hyperextension.

In testing hyperextension, the standing patient is asked to place the palms in the small of the back, bend backward, and then move the hands distally down the buttocks and the back of the thighs as far as possible. The examiner's fingertips should be placed in the lumbar interspinous spaces to note segmental motion. Extension occurs from above downward. The maximum range of motion, and the production, increase, or reduction of pain and its distribution should also be evaluated. Before concluding this part of the examination, the examiner should test the effects of repetitive loading in standing extension.

Restricted extension is usually the result of fixation at the posterior motion unit that prevents facet gliding. Increased pain during hyperextension suggests a rotational subluxation. When a fixed posterolateral herniation is present, the patient will have restricted extension with deviation away from the side of pain.

The Sitting Position

McKenzie's studies indicated that "almost all low back pain is aggravated and perpetuated, if not caused, by poor sitting postures in both sedentary and manual workers." Thus, observing a relaxed patient's posture during the history and examination will tell the alert examiner almost as much as the history of low back pain itself.


During evaluation, the patient should be instructed to sit on an examining stool, thus immobilizing the pelvis, and asked to rotate the trunk first to one side and then to the other. Lateral bending is then conducted, bilaterally. Then the patient flexes and then extends the spine, and the integrity of the column during these movements is observed. Any abnormal motion or restriction should be noted.

The typical sitting posture leading to low back pain is characterized by the common decrease or the less common increase of the normal lumbar curve to the extent that the involved ligaments are placed under maximum stretch for a prolonged period. This eventually leads to pain. As few chairs contain a lumbar roll to maintain the normal lordosis, the longer a person sits in a relaxed position, the more the muscles relax and weight-bearing stress must be absorbed by the ligaments. Thus, if poor sitting posture (eg, lumbar flexion) is within the patient's history of low back pain, continued poor sitting posture will perpetuate the problem and often enhance the symptoms while seated or when arising from a seated position. Likewise, if symptoms are aggravated by prolonged sitting, it is evident that sustained flexion is causing a mechanical deformation and therapy should emphasize lumbar extension. If symptoms are relieved by prolonged sitting, a diagnostic clue has been gained indicating that therapy should be directed to obtaining sustained flexion.

People who habitually sit with the lumbar area stretched (flexed), constantly place abnormal tension upon the weak posterior aspect of the anuli, paravertebral soft tissues, and facets of the posterior motion units. In addition, habitual sitting in lumbar flexion leads to a loss in the range of motion of lumbar extension, which influences segmental motions during sitting, standing, and gait.


Body weight in the erect sitting posture should be supported upon the ischial tuberosities and the adjacent soft tissues. The center of gravity is forward of the ischii, the lumbar lordosis is but slightly flattened, and about 25% of body weight is transmitted to the floor through the lower extremities. In the slouched sitting position, however, the center of gravity is posterior to the ischii, the lumbar lordosis is reversed, and far less body weight is transferred to the floor via the lower extremities.

The degree of the lumbar curve during the sitting posture depends upon sacral angulation that is governed by pelvic posture and the degree of mobility of the involved segments. Lumbar IVD pressure is higher during sitting than in the standing posture because intradisc pressure increases with the tendency toward lumbar kyphosis.


A spinal segment always rotates or deviates into a distortion pattern with greater ease than out of the distortion pattern. For example in the upper spine, if the atlas shows a left lateral shift, right lateral flexion of the head is greater than the same effort to the left. If the upper cervical segments indicate vertebral body rotation to the right, the head and neck actively and passively rotate to the right with greater ease than to the left. If there is a right cervicoscoliosis, the patient can laterally flex his neck to the left much more readily than to the right. The same principles apply in the thoracic and lumbar regions. If there is a right structural scoliotic deviation of the lumbar area, the patient sitting, with pelvis fixed, will find it easier to rotate the torso to the right than to the left. Lateral flexion will be further on the side of concavity than the side of convexity.

The Prone Position

With the patient in the prone position, a re-examination by palpation of the spinous processes, transverse processes, and paravertebral musculature should be made. It is important that the patient lie on a flat surface rather than on a table with built-in convolutions that may confuse findings.

As the patient lies prone, the dots over the spinous processes should again be observed. They may be quite altered and decidedly changed from their appearance in either the anatomic or Adams position. A stiff distortion of the spinal column may suggest spondylitis deformans. In this condition, the movements of the spine are diminished or may perhaps eventually be lost. In spondylitis, the curvatures of the spine are not influenced by movements or by changes in the examining position of the patient. In fact, many spinal curvatures and disorders might be missed if the spine is examined with the patient only in the prone position.


A scoliosis will sometimes exhibit a lordosis and a somewhat anterior curvature of the spine between the scapulae. When this condition exists, there is generally a flattening of the anterior curvature of the lumbar vertebrae.

In conditions where the paravertebral musculature is weakened, we may see a lateral curvature of the spinal column with no appreciable rotation of the vertebra. This lateral deviation will disappear when the patient assumes different positions. The paravertebral muscles can be weakened by long illness, chronic degenerative conditions, malnutrition, or by chronic hysteria or emotional stress.

In common pelvic mechanical problems on the side of involvement,

(1) the PSIS palpates in comparison with that of the opposite side as being prominent and inferior due to the posterior innominate rotation;
(2) the ischial tuberosity palpates as being less prominent and anterior; and
(3) the spinous process of S1 approximates the PSIS on the side of involvement due to the anteroinferior shifting of the sacrum which carries its centrum toward the posterior innominate.


A patient's spine is automatically placed in extension when the prone position is assumed. In testing hyperextension, the prone patient is asked to lift his trunk upward by extending his elbows, yet keeping his lower pelvis firm against the examining table. This is similar to a push-up where the pelvis is not raised. A much greater degree of lumbosacral hyperextension can be achieved in the prone position than in the standing position. As in the other tests, the examiner's fingertips should be placed in the lumbar interspinous spaces to note segmental motion and the maximum range of motion and the production, increase, or reduction of pain and its distribution should be evaluated. Before concluding this part of the examination, the examiner should test the effects of repetitive loading in recumbent extension.

A small disc protrusion should be reduced by segmental extension, thus extension should relieve pain. However, an entrapped fragment or protrusion would not be benefited and may be aggravated.

The Supine Position

In the horizontal positions, the lumbar spine is in extension when a person is supine on a firm mattress or prone on either a firm or soft mattress. The lumbar spine is in flexion when a person is supine on a hammock or an extremely soft mattress. In the relaxed lateral recumbent position, the lumbar region glides laterally (with some coupled rotation) toward the floor --especially if the mattress is soft.


In common pelvic mechanical problems on the side of involvement:

(1) the ASIS palpates as being superior,
(2) there is increased tenderness over the lateral portion of the inguinal ligament, and
(3) there is increased tenderness over the origin of the sartorius muscle.


The supine patient is asked to grasp the flexed knees, pull them toward the abdomen, and flex the neck forward in an attempt to touch the forehead between the knees. In this position, flexion should occur from below upward and a greater stretch is placed on the lumbosacral area than can be achieved in the standing position. The examiner's fingertips should be placed in the lumbar interspinous spaces to evaluate segmental motion. At the same time, the examiner should note the maximum range of motion and the production, increase, or reduction of pain and its distribution. Before concluding this part of the examination, the examiner should test the effects of repetitive loading in flexion.


Genetic factors frequently leave the lumbar spine in defect and instability, and the gross and subtle implications of anteroposterior balance, lateral balance, and rotational balance are manifold. The incidence of low back disorders of a protracted and recurring nature is much higher in those patients whose spines show evidence of development defects and anomalies. This is especially true in the young.

Bipedism greatly augments the mechanical and neurologic complications of the lumbosacral complex. Such lumbosacral defects and complications as asymmetrical facet facing, imbrication, sacralization (especially the pseudo type), lumbarization, pars defect, discopathy, iliotransverse ligament sclerosing, retrolisthesis and L5S1 reverse rotation are important concerns. Bertolotti' syndrome is occasionally seen, which consists of sacralization of L5 in association with sciatica and scoliosis.

Body weight during development wedges the sacrum between the innominates because of their peculiar laterally inclined planes. This allows the sacrum to move inferior, anterior, and medial, coupled with the anteroinferior angulation of the sacral base. Many of the abnormal orientations found in the lower spine are because the lumbar facet joints are not determined until the secondary curves are developed in the erect position. Forces imposed during maturation contribute greatly to the high incidence of asymmetry.

      Facet Angle Variations

Interspinal posture is directed by the facet facing of each posterior intervertebral joint, with altered facings most commonly occurring in the lumbar and lower cervical regions. Articular facings are altered more frequently between L4 and L5 than at any other level in the vertebral column.

Normal symmetrical facets glide with little friction produced. However, if the facets deviate in their direction of movement, the unparallel articulating surfaces "scrub" upon one another. Over a period of time even in the absence of overt injury at the level of abnormality, articular variations will present marginal sclerosis. This hardening is usually followed by hypertrophy or exostosis. Coexistent with this finding, the interarticular spaces gradually become narrowed, hazy, obscured, and even obliterated on x-ray films.


Strong abdominals and posterior thigh muscles are necessary to prevent thoracic hyperkyphosis, lumbar hyperlordosis, and visceroptosis. Weakness leads to visceroptosis which in turn tends to produce lumbopelvic sagging and compensatory thoracic hyperflexion. Strong abdominals and hamstrings keep the pubic arch horizontal so that most visceral weight is in the basin. This inhibits pelvic tilt and hyperlordosis.

In the upright position, the greater the lordosis, the greater the compressive forces upon the posterior elements of the vertebral segments and the greater the shearing forces on the discs. The greater the lordosis, the more

(1) the IVFs are narrowed,
(2) the posterior discs are compressed and bulged, and
(3) the higher the intradisc pressure.

An increase or decrease in the sacral angle determines the direction of the lumbar spine. These A-P changes must be made within the lumbar spine because of the different facet angles and degree of stiffness of the thoracic spine. Cailliet feels that 75% of all postural low back pain can be attributed to hyperlordosis, while Barge contributes most low back pain to lumbar kyphosis. Unfortunately, such figures are useless when dealing with an individual patient.

Regardless of the degree of lordosis, L3 is usually fairly horizontal, thus it is subjected to minimal shear forces. It is for this reason that L3 in hyperlordosis is usually asymptomatic unless the forces on its posterior elements produce symptoms such as in "kissing" spines.

During lateral bending in the erect position, considerable rotation accompanies the abduction motion if there is a significant degree of lordosis. However, if the lumbar spine is relatively flat or if the lateral bending is performed in the sitting position, the amount of associated rotation is minimal.

The intertransverse spaces of the normal spine open on the convex side and approximate on the concave side. In distinct lordosis, however, the facets are relatively locked and lateral flexion is so restricted that the vertebrae must severely rotate (far more than the normal coupling motion) to allow lateral bending.

Lumbar Scoliosis

When the spine is in good alignment, facet articulation offers minimal friction. In primary lumbar scoliosis, the articular surfaces are no longer parallel and the result is articular friction leading to impingement, erosion, and arthritis. This is the result of normally reciprocal articulating surfaces operating in an oblique position.


Scoliotic distortions that result from a structural deficiency such as an anatomically short femur or leg, a flattened longitudinal arch while standing, an axially short ischium while sitting, or a wedged vertebral segment produce distortions referred to as static curvatures. Curvatures arising from locomotion dysfunctions (eg, pelvic subluxation-fixations, contractures, paralysis) are called curvatures of disturbed motion or dynamic curvatures. Illi's studies have shown that most scolioses classified by allopaths as primary lumbar scolioses have their origin in sacroiliac dysfunction, but any disturbance in movement may give rise to such a curvature.


An understanding of Lovett's principles and the basic types of lumbar scolioses offers insight into distortion analysis. Lovett's principles state that if the base of a weight-bearing segmented column such as the spine is caused to tilt (eg, unilateral anteroinferior sacral subluxation), the center of weight bearing will shift toward the high side of the base because it is the shortest distance between the point of weight origin and weight reception. The involved segments will then seek to escape the load by shifting and rotating to the opposite side. See Table 12.6.

     Table 12.6. Lovett's Classification of Lumbar Scoliosis

Lovett positive scoliosisIn a Lovett positive scoliosis, the axis of vertebral rotation in the lumbar area is posterior to the articulating processes. When the segments are asymmetrically loaded, the bodies of the involved segments normally deviate farther from the midline than their spinous processes.
Lovett excess scoliosisIf a Lovett positive scoliosis occurs that is far more than that demanded by the base inferiority, the condition is referred to as an excessive Lovett positive. This state is usually attributed to an iliopsoas spasm on the side of concavity that accentuates the curve beyond the norm.
Lovett negative scoliosisIf a lumbar scoliosis shows that the spinous processes have deviated from the midline further than the vertebral bodies, the condition is said to be atypical (negative). A negative scoliosis is indicative of marked muscle involvement. The common causes of this muscle involvement are:

(1) muscle spasm associated with facet irritation (eg, jamming, instability);
(2) disturbed or incompatible movement dynamics (eg, subluxation, fixation);
(3) local unilateral muscle contraction as the result of noxious viscerosomatic reflexes (eg, viscera pathology);
(4) antalgic splinting, resulting in scoliotic deviations whose transverse planes are almost completely horizontal. If left uncorrected, such antalgic curves will eventually produce a secondary sacroiliac distortion that will compromise normal lumbopelvic dynamics.


The features of this deformity are scoliosis and/or alteration of the normal A-P curves where there is no apparent structural basis. The distortion is associated with muscular weakness or spasticity such as of the psoas in the lumbar spine or the sternocleidomastoideus in the cervical spine; postural imbalance and interference to normal locomotive effort; muscular soreness and fatigue; irritative microtrauma to all involved vertebral motion units; compensatory curvatures; and biomechanical stress transmitted throughout the spinal column.


In this distortion, the characteristics are an unleveling of spinal support due to anomaly, trauma, or pathology where the structural unleveling of the spine above tends to portray a normal compensatory response if the motion units are functional. The situation signifies general postural incompetence and interference to the normal locomotive effort; muscular tension, soreness, and fatigue; irritation of the involved motion units; compensatory curvatures; and a biomechanical insult transmitted throughout the spinal column.


In studying spinal distortion patterns, it is well to keep in mind Logan's rule: "The body of the lowest freely movable vertebra always rotates towards the lowest side of the sacrum or the foundation upon which it rests." This gravitational effect has a mechanical advantage in that as the thicker anterior aspect of the lower lumbar vertebrae and their discs rotate away from the midline there is a mechanical compensation created axially to make up mass height for the sacral inferiority to where the apical segment becomes horizontal. Above the apex where the increase in mass has created a superiority, the vertebrae tip toward the concavity and rotate "uphill." This in turn produces an inferior base for the lower dorsal vertebrae on the contralateral side, and a secondary curve develops.


There is also a distortion of the pelvis as a whole in sacroiliac misalignment. For example, if the sacral base slips anteroinferior on the right with the right ilium rotating posteriorly on the sacral base, the pelvis as a whole will tend to rotate anteriorly on the right to keep body weight centered over the head of the femur because the acetabulum has translated superiorly.

Spinal Stenosis

Several congenital or acquired factors may be responsible for narrowing of the vertebral canal or IVF. Movements that would never produce symptoms in the normal spine will often cause difficulty in the spine whose vertebral canals are narrowed. The common factors are congenital narrowing, degenerative hypertrophic stenosis of the anterior or posterior elements, posterior or posterolateral disc herniation, spondylolisthesis, posttraumatic stenosis, postsurgical stenosis, pathologic stenotic enlargement (eg, Paget's disease), ligament thickening or buckling, or a combination of these factors. In unusual cases, tumors, cysts, and inflammatory swelling may be responsible.

In most cases, regardless of the initial cause, the process progresses from IVD degeneration to apophyseal arthritis, segmental instability, and various attempts of repair that result in fibrotic or new bone encroachment on the cord, nerve root, arteries, veins, or a combination of factors. The most common sites are at the L3L4 or L4L5 level. When spondylosis is accompanied by spinal stenosis, cauda equina claudication is likely.

When a case becomes symptomatic, constant or intermittent pain may be local or referred to the lower extremities, especially in the posterior thighs and calves. Muscle weakness, sensory deficits, and reduced circulation of the lower extremities that differ bilaterally are usually associated. Exercise usually aggravates the symptoms, but walking often relieves night pain if there is circulatory impairment.


Many authorities consider spondylolisthesis congenital, while others are of the opinion that trauma in early childhood is more often responsible. Regardless, when witnessed in an adult, the lesion usually dates from childhood rather than from some recent injury. Rehberger states that it occurs in 4%6% of the population, but it is present in about 25% of people complaining of chronic backache.

An increase in the S1 sagittal diameter in spondylolisthesis occurs during teenage maturation. Displacement tends to increase before the age of 30, but this tendency sharply decreases thereafter unless there is an unusual cause such as chronic fatigue coupled with a prolonged unusual posture. Predisposing spinal instability is frequently related to a degenerated disc at the spondylolisthetic level.


The anterior or posterior sliding of one vertebral body on another (spondylolisthesis or retrolisthesis) usually results from either traumatic pars defects or degenerative disease of the facets. Congenital, acquired, or pathologic factors may also be involved or superimposed. There is a separation or elongation of the posterior motion unit from the anterior motion unit which allows the vertebral body to slip forward on the segment below, carrying with it a portion of the neural arch and severely altering weight distribution.


The lesion is frequently asymptomatic during the first two decades of life. Dimpling of the skin above the level of the spondylolisthesis may be observed or extra skin folds may be seen because of the altered spinal alignment. A distinct "step off" or depression is usually palpable. Hamstring tightness of a varying pattern, a flattened heart-shaped buttocks when viewed from the posterior, and flared ilia are commonly associated during youth, but nerve root irritation is rare until adulthood. Lasegue's test is resisted and accommodated by early posterior rotation of the pelvis. Restricted hip flexion is often obvious in gait.

When the condition becomes symptomatic, the pain is usually recurrent and increases in severity with subsequent episodes. Low back pain often develops after insignificant injury or strain, with recurrent pain gradually increasing in intensity. A functional scoliosis is invariably associated that reduces as pain subsides. Weakness, fatigue, stiffness, unilateral or bilateral sciatic pain, and extreme tenderness in the area of the spinous process of L5 are associated. The pain usually subsides in the supine position.


As with spondylolysis, the most common site of spondylolisthesis is in the lower spine, but it has been reported in all areas of the lumbar spine and the cervical area. The typical situation is sliding of L5 on the sacral base (75%80%) or of L4 on L5. The integrity of the disc is best analyzed through neutral, flexion, and extension views.

The grading of spondylolisthesis is made by dividing the superior surface of the base segment into four equal parts when viewed in the lateral film: the Meyerding method. The part occupied by the posterior-inferior tip of the vertebra above indicates the degree of forward slip.

In suspected cases where no obvious gross slipping has occurred, the Meschan method is used on the lateral projection. A line is drawn across the posterosuperior and posteroinferior tips of the L5 vertebral body. A second line is drawn from the posterosuperior tip of the sacrum to the posteroinferior tip of L4. Normally, these two lines should overlap or nearly so. If they are parallel or form an angular wedge at the superior, it indicates an anterior movement of L5. If the lines are separated more than 3 mm, a spondylolisthesis is present.

Flexion and extension studies in lateral projections can be utilized to determine the degree of instability. The degree of angulation formed in flexion is subtracted from the degree of angulation formed in extension, as the maximum degree of slippage is seen during extension. The result of these two measurements offers an appraisal of the degree of instability present.

Oblique views show a defect in the isthmus or pars interarticularis where the neural arch is visualized as a picture of a terrier's head. The pedicle and transverse process form the head of the dog, the ears by the superior articular process, the neck by the pars interarticularis, the body by the lamina, and front legs by the inferior articular process. When the defect appears as a collar on the dog, a spondylolysis is present. If the terrier is decapitated, a spondylolisthesis is present. In some cases, spondylolisthesis develops without spondylolysis by osseous elongation of the pars interarticularis and pedicles. This is usually attributed to bone softening or a congenital alteration from the norm.

Other roentgenographic findings include an unusual lumbar lordosis with increased lumbosacral angle and overriding of facets adjacent to the defect which is usually visible on the A-P view. In time, the overriding apophyseal joints show osteoarthritic changes. The amphiarthrodial joint between the vertebral bodies frequently shows narrowing, spurring, and associated osteoarthritic changes. A functional lumbar kyphosis is sometimes associated, indicating the possibility of a herniated disc.


Retrolisthesis is often the result of some infectious or degenerative disc process according to Finneson, but Gehweiler feels that such changes may be absent. It is most common at the L2 and L1 segments, and is occasionally seen at the L5S1 joint where it is usually associated with a traumatic herniated disc. Some authorities feel the cause can be attributed to a decreased sacral angle that flattens the lumbar lordosis and forces the upper lumbar segments into kyphosis.

Regardless of the initial cause, the disc space narrows and the posterior facets compress and "telescope" as the superior segment tends to slide posteriorly upon the inferior segment of the motion unit, which tears or at least stretches the posterior aspect of the capsules. This process establishes a chronic inflammatory process within the apophyseal joints that is easily aggravated by stretching of the involved posterior elements (eg, flexion, hyperextension). The result is pain and spasm of the erectors.

Spondylolysis and Spondylosis

The term spondylolysis literally refers to the destruction of vertebral structure and spondylosis refers to vertebral ankylosis. Thus, they can be considered the first and second stage of the same degenerative process. Spondylolysis is similar to spondylolisthesis in that there is also a defect in the pars interarticularis, but there is no anterior slipping of the vertebral body. Disc narrowing and facet sclerosis are usually associated. In time, a picture of degenerative arthritis, ankylosis, and IVF narrowing is produced.


Spondylolysis is a degenerative condition generally associated with early middle life. The most common site of spondylolysis is in the lower spine. There is a high incidence of trauma and strenuous physical activity in the history of spondylolysis such as fatigue fractures from falling on the buttocks. It is more common to males and often associated with athletic or occupational overstress.

Spondylolysis is more common in the obese, robust, endomorphic individual. A large percentage of cases show a degree of associated spondylolisthesis, usually with normal neurologic signs. Because of chronic lumbar overstress, heavy lifting is commonly associated with an increased incidence in spondylolysis and disc herniation at the lower lumbar area. Infrequently, vertebral body fracture is associated.


The associated disc narrowing is the result of anular tears that decrease intradisc pressure and allow the vertebral bodies to approximate and the IVFs to narrow. As the process continues, the involved disc becomes dehydrated and thinning increases. Elastic anular fibers become replaced by fibrous tissue. The ligamentum flavum may buckle and/or the anulus may exude between the ligament and the vertebral body and form a hard mass (ie, canal stenosis). The ligamentum flavum rarely thickens in itself: the appearance of thickening is due to underlying laminal growth and a layer of superimposed fibrous tissue. The anterior longitudinal ligament may also weaken and lead to spur formation.

This process of disc and associated tissue destruction places excess weight on the apophyseal facets. The capsules weaken and allow increased shear, and this produces joint synovitis, articular degenerative changes, capsular thickening, adhesions, osteochondral fractures, loose bodies in the joint, and possible nerve root entrapment.


The findings are primary changes in the IVD with progressive loss of turgor and elasticity contributing to softening and weakening of the disc margin. Marginal spurring, lipping, and the consequence of osteophytic formation ensues. The sacroiliac areas are not usually involved. Narrowing of one or more IVD spaces may develop when the disc space together with changes in the curvature of the spine appear narrowed. The clinical picture, often associated with spondylosis deformans, is usually referred to the area of structural deformity that results in compromise of contour and diameter of the related IVF.


Because the spine is never completely static, even during sleep, proprioceptive activity and its neuromuscular responses are continuous throughout life. If structural disrelationship exists, neural firing is magnified by increased muscle stretch, hypertonicity, ligament tension, and abnormal joint position to the point of unconscious central bombardment. The result is fatigue, muscle soreness, likely myofibrosis, and possible osteoarthritis.

Excessive hypertonicity of a muscle, confirmed by palpatory tone and soreness, will tend to subluxate its site of osseous attachment. A listing of common problem areas in the lumbar area is shown in Table 12.7.

     Table 12.7. Selected Effects of Hypertonicity in the Lumbosacral Area

MuscleEffect of Prolonged Hypertonicty
Erector spinaeThis muscle group arises from the iliac crests, sacrum, and spines of the L5-T11 segments, then splits and inserts as iliocostal, longissimus, and spinal muscles. Hypertonicity puts the lumbar area into hyperlordosis.
Iliocostalis lumborumExcessive tone tends to pull the pelvis superior and posterior and the rib cage and lower thoracic transverse processes inferior and anterior.
InterspinalesHypertonicity tends to hyperextend the segments affected.
Latissimus dorsiIncreased tone tends to pull the lower half of the spine and the pelvis anterior, lateral, and superior.
MultifidusExcessive tone tends to rotate the lumbar spine by pulling the involved spinous processes anterior and lateral.
Psoas majorIncreased tone tends to pull the lumbar spine into anterior and inferior flexion.
Quadratus lumborumHypertonicity tends to subluxate the ilium superiorly and to pull the 12th rib and the lumbar transverse processes posteroinferior.
Rectus abdominisIncreased tone tends to roll the pubis superior and posterior and the medial thorax inferior.

Once abdominal infection is ruled out, hypertonus of the abdominal wall can be secondary to primary pelvic fixations. Gillet feels these are often related to sacrotuberous ligament shortening, shortening of the lumbar anterior longitudinal ligament, or pubic articular fixation.

Muscle Enlargement vs Hypertrophy.   Hypertrophy and spasm must be differentiated from the muscular enlargement which follows exercise. The increase in muscle bulk following prolonged exertion is caused by two factors:

(1) the opening of capillaries during activity that are closed during rest, and
(2) prolonged activity appears to increase the size of individual muscle fibers.

This latter point is thought to be from an increase in sarcoplasm. A few authorities believe that even the number of myofibrils may increase during increased exercise over several weeks. If this is true, it rescinds the old "law" that the quantity of muscle fibers does not increase after birth.


The trunk is held erect by the flexors and extensors of the spine and the extensors of the hip. The muscles and ligaments that hold the trunk erect are much stronger as a whole than those of the pelvis. After a long illness, for example, a patient can sit erect long before he can stand. The abdominal muscles offer considerable protection to the viscera when active, but when they are relaxed, they are easily damaged by intrinsic or extrinsic forces. This is especially true of the rectus abdominis.


Trunk raising from the lateral recumbent position exhibits the strength of lateral flexors of the trunk and hip abductors. Leg raising from the supine position is a two-phase combination between strong abdominals and strong hip flexors.

Because A-P trunk motions are the most common movements used in daily living and inasmuch as flexion is assisted by gravity, the spinal extensors are the most important muscles of the trunk from a biomechanical viewpoint. It is also for this reason that back muscles are rarely weak unless paralysis is present. Kendall places the incidence of weak spinal erectors at less than 1% in the nonparalytic. When signs of extension weakness are evident, differentiation must be made between weak spinal extensors and weak hip extensors.


Oblique Shortening.   Bilateral shortening anteriorly reduces the sternopubic distance. This tends to produce a flat chest and a long thoracic hyperkyphosis. Unilateral lateral shortening of both obliques reduces the rib-ilium space and produces a C curve with a contralateral convexity. Ipsilateral shortening of the external oblique with contralateral internal oblique shortening produces a scoliosis. Bilateral shortening of the internal oblique and lateral stretchingm of the external oblique produces the anterior rotation of the pelvis and thoracic hyperkyphosis so often seen in a "slumped" posture.

Oblique Weakness.   Weakness in the abdominal oblique muscles is exhibited by decreased respiratory efficiency and loss in abdominal support. Trunk flexion and posterior pelvic tilting strength are diminished in bilateral weakness. This is overtly suggested by anterior pelvic tilt and lumbar hyperlordosis or an exaggerated S curve laterally. Ipsilateral weakness of the external oblique with contralateral weakness of the internal oblique encourages lumbar scoliosis with rotation and tilting, while unilateral weakness of these two muscles promotes a C curve toward the side of weakness.

Rectus Abdominis Weakness.   Weak recti are portrayed by a loss in trunk flexion and posterior pelvic rotation strength. In the upright posture, a lengthening of the sternopubic distance, a lumbar hyperlordosis, and an anterior pelvic tilt will be evident. The rectus is rarely shortened by itself.

Transversus Abdominis Weakness.   Weak transversarii are exhibited best by the lateral bulging of the flanks during arching of the back in the prone position.

     Low Back Pain

Low back pain has been the second most frequent health complaint in the United States for many years, second only to headaches. More lost working hours are attributed to this affliction than any other factor, and the vast majority of these complaints find their cause in biomechanical failures. These failures are often complex, accumulative, and subtly hidden by the body's marvelous adaptive mechanisms --a diagnostic challenge when pain is solely referred.


Because of its prevalence, backache requires a meticulous consideration of all possibilities, a comprehensive case history, and a systematic examination associated with necessary laboratory data and x-ray findings. In addition, emotional factors must be considered. In eliciting the case history, the manner of onset, location and nature of pain and spasm, aggravating and relieving factors, and a thorough systems review are almost mandatory if professional justice to the patient is to be achieved.

The Lumbar Nociceptive Receptor System. The lumbar ligaments and fascia are richly innervated by nociceptive receptors. When the lumbar spine is in a relaxed neutral position, its nociceptive receptor system is relatively inactive. However, any mechanical force that will stress or deform receptors, with or without overt damage, or any irritating chemical of sufficient concentration will depolarize unmyelinated fibers and enhance afferent activity. Thus, the pain experienced after either intrinsic or extrinsic trauma can be the result of mechanical factors, chemical factors, or both.

Mechanical Pain. Normal mechanical force applied to normal tissue does not produce pain. However, abnormal mechanical deformation occurs whenever:

(1) abnormal stress is applied to normal tissues (eg, postural pain),
(2) abnormal stress is applied to abnormal tissues, or
(3) normal stress is applied to abnormal tissues (eg, soft-tissue shortening).

Pain from mechanical causes is sharp, acute, and occurs immediately. If mechanical pain does not occur until several minutes or hours after an activity, it is most likely that the position assumed following the activity is the cause of the pain rather than the activity itself.

Mechanical pain may be intermittent, appearing and disappearing, or vary in intensity according to aggravating and beneficial circumstances. It is usually intermittent because of increased and decreased mechanical deformation forces.

In cases of pain of mechanical origin, the examiner should always be able to reproduce the patient's symptoms by test movements. Constant pain from constant mechanical deformation (eg, irreducible disc protrusion) is always possible but not common. The rule to remember is that pain of mechanical origin is always affected by movement, for better or worse.

Chemical Pain.   Chemical irritants accumulate in damaged tissue soon after injury. As soon as the nociceptive receptor activity is enhanced, pain will be experienced. Chemical irritation can be the result of any inflammatory, infectious, or traumatic process of sufficient degree. It can also be the result of any abnormal metabolic by-product, especially that of ischemia, of sufficient concentration to irritate free nerve endings in involved tissues.

In contrast to pain of mechanical origin, pain from chemical causes is constant, dull, and aggravated by normal movements as long as the chemical irritants are present in sufficient concentration. It may not occur until several minutes or hours after an injurious event has taken place. Chemical pain subsides during the natural healing process as scar tissue forms. Rarely does chemical pain from trauma extend past 20 days after the precipitating accident.


Because more research has been done on the IVD than any other structure, there is a tendency to attribute almost any type of backache to some type of disc disorder. This leads to tunnel vision because many disorders, both spinal and extraspinal, may simulate disc disease. See Table 12.8. The most common causes of nondisc functional pain are postural fatigue, spinal strains (acute and chronic), and IVF syndromes. Certain pelvic disorders may also be involved such as chronic abdominal collapse, sacroiliac sprain, and coccygeal stress.

The major predisposing factors to low back pain appear to be a poor sitting posture, a loss of motion within the normal range of lumbar extension, and/or excessive hyperflexion activities. The primary precipitating factors usually involved are a sudden stress at an unguarded moment or lifting with inadequate mechanical advantage.

Common Problems in Children.   Intrinsic backache is not frequent in the preadolescent. When it occurs, it is painfully acute and has its highest incidence in the thoracic or thoracolumbar spine. The typical clinical picture exhibits severe antalgic spasm, thoracolumbar hyperkyphosis, muscular tenderness, no bony tenderness, positive Lasegue's sign, tight hamstrings, and negative roentgenographs. These signs suggest instability that is rarely confirmed by physical examination alone. Initial differentiation must be made from forgotten trauma and early Scheuermann's disease. Relief usually comes spontaneously after rest, but idiopathic episodes may occur and then disappear with further maturation.

Common Problems in Adulthood.   A loss of tissue elasticity and other signs of repeated trauma or degeneration are common during middle age. Quite frequently, psychologic stress superimposed on a biomechanical fault precipitates episodes of backache. The overt symptoms are increased by activity and relieved by rest. These must first be differentiated from the claudication-type backache and butock pain associated with aortic block, aneurysm, and spinal stenosis. After severe trauma, Helfet/Gruebel Lee describe the vertebral degenerative process as follows: compression injury fractures the end plates which leads to disc and posterior joint changes. In following years, new bone forms markedly on the posterior articular processes and this leads to spinal stenosis at the level of injury. Fixation at this level produces added stress above and below leading to extension of the degenerative arthritis and spinal stenosis.

Common Problems in Senior Citizens.   In treating the fragile elderly, the cardinal concerns in both diagnosis and therapy are arteriosclerosis, demineralization, and diminished collagen. These disorders are said to seriously affect 25% of females and 18% of males over 70 years of age. Symptoms first arise in those joints under the greatest chronic stress such as at the hip joint and the T11L1 area. The loss of systemic collagen will be most noticeable on the dorsal aspect of the hands, where the skin will appear atrophic, thin, marbled and capillary fragility will usually be apparent. Unless the metabolic defect can be corrected, progressive thoracic kyphosis, pulmonary symptoms, disc degeneration and failure, vertebral collapse, and wedge fractures can be expected.


Abnormal reflexesKyphosisPyrexia/chills
Associated remote painLocal heatRemote pain
DysmenorrheaNight sweatsSkin resistance changes
Gait abnormalitiesPelvic massUnequal leg length
HematuriaPostural changesWeight loss


CBC and differentialSerum acid phosphataseSerum phosphorus
Chest x-raySerum alkaline phosphataseSerum total protein
ECGSerum amylaseUrinalysis
G-I seriesSerum calciumUrine Bence-Jones protein
Sedimentation rateSerum lipaseVD serology
EMGSpinal roentgenography 

     Table 12.9. Low Back Pain and Associated Symptoms

Syndrome: Low Back Pain +Primary Suspect Disorders
DysmenorrheaEctopic pregnancy
Fibroid uterus
Retroverted uterus
Subluxation complex
Epigastric painCholecystitis
Duodenal ulcer
Hiatal hernia
Intestinal obstruction
Low rib fracture
Pancreas tumor
Subluxation complex
HematuriaPyelonephritisRenal calculus
Local, no radiationLumbosacral sprain
Metastatic carcinoma
Pelvic inflammation
Rheumatoid spondylitis
Pelvic massKidney tumor
Ovarian cyst
Ovarian tumor
Pancreatic tumor
Rectal carcinoma
Uterine tumor
PyrexiaEpidural abscess
Hodgkin's disease
Perinephric abscess
Retrocecal appendicitis
Tubo-ovarian abscess
Radiation to leg and positive Lasegue's signCauda equina tumor
IVD syndrome
Pelvic tumor


Various classical types of low back pain syndromes are shown in Table 12.10. In recent years, however, McKenzie developed a new approach to the classification of low back pain syndromes. He describes a derangement, dysfunction, and postural syndrome.

     Table 12.10. Types of Low Back Pain Syndromes

NeurogenicBack pain derived from lesions in the CNS, spinal cord, and cauda equina, excluding extradural compression of emerging nerve roots.
SpondylogenicBack pain derived from disorders of the spinal column and its associated structures. Spondylogenic back pain can be subclassified as follows:
  1. Discogenic:   Back pain with or without sciatica resulting from structural changes in the IVDs. These can be divided into two major groups: (a) Disc degeneration, giving rise to back pain with or without referred pain to legs, without evidence of nerve root compression. (b) Disc rupture, giving rise to radicular pain with or without backpain, always associated with signs of nerve root tension, and occasionally with evidence of impairment of root conduction.

  2. Osseous:   Pain derived from pathologic changes in the bony components of the vertebral column and sacroiliac joints: traumatic, inflammatory, infective, neoplastic, metabolic, and structural (eg, scoliosis, spondylolisthesis, and spinal stenosis).

  3. Soft tissue:   Pain derived from traumatic and degenerative changes in muscles, ligaments, and fascia.

  4. Psychogenic:   Two groups of emotional disorders should be recognized when assessing disability in contradistinction to pain: (a) Psychogenic regional pain; the development of backache and/or sciatica without any underlying pathologic disorder. (b) Psychogenic magnification of pain; emotionally-based exaggeration of pain produced by a pathologic disorder resulting in inappropriate disability.

VascularBack pain and/or sciatic pain derived from changes in the aorta and vessels in the lower extremities.
ViscerogenicBack pain derived from disorders of visceral structures.

     Table 12.11. McKenzie's Classification of Low Back Pain Syndromes

  Type of Syndrome
Cardinal signsIntermittent pain and partial or complete loss of extension motion.Intermittent pain and partial loss of motion are typical. A loss in extension motion is commonly associated with a flattened lumbar region; a loss in flexion motion is commonly related to hyperlordosis.Intermittent pain, relieved by a position change.
PainUsually intermittent discomfort, but sometimes episodes of pain extend over many hours.In the restricted plane of motion, pain will be produced by passive manipulation prior to the end of the normal range of motion; ie, when the fibers of the shortened tissues reach their functional limit. Conversely, this pain subsides within minutes when the overstress is discontinued.Pain, intermittent in character, is increased on active motions but not on passive manipulation. Syndrome is initiated by certain postures and positions that induce a dull ache that later progresses into acute pain minutes or hours after the aggravating activity. Conversely, this pain subsides with a corrective change in position or posture.
Physical effortPartial restriction of passive movement in one or more planesPartial restriction of passive movement in one or more planes. Subjective stiffness is greater after rest (eg, in the morning) and less after exercise.No loss of passive motion.
Position of reliefRelief is usually found in the prone position (lumbar spine in extension) in typical posterolateral or posterior herniation. It may require 10-20 minutes of complete relaxation in this position for the protruded anulus to recede. This position may be initially uncomfortable to the patient, but the pain should subside distally when complete relaxation is attained. Rarely, the nucleus migrates anteriorly, making the prone position contraindicated.Pain eased in the supine position (lumbar spine in flexion) when extension loss is present; prone position (lumbar spine in extension) when flexion loss is present. Although these positions afford temporary relief, they also contribute to chronic structural deformation.Any position of rest of the involved soft tissues eases the discomfort.

The Derangement Syndrome.   The derangement syndrome features internal derangement of the IVD, causing mechanical deformation of soft tissues (eg, end plate, anular, or nuclear alterations) that results in an abnormal position of function of the involved spinal segments. It should be noted, however, that fixations producing dysfunction are far more common than IVD derangements. See Table 12.11.

The Dysfunction Syndrome.   The dysfunction syndrome features pathologically involved muscles, ligaments, fascia, apophyseal joints, and the IVD. The major factor is adaptive soft-tissue shortening (fixation) of the motion unit causing chronic mechanical deformation and loss of joint play prior to ligamentous restraint. The precipitating cause is usually a by-product of trauma, spondylosis, or poor posture. If end motion in a certain plane causes pain or discomfort, the patient will avoid such movement and the tissues will shorten to accommodate the more limited range of motion. Symptoms do not subside rapidly in dysfunction syndromes because the involved soft tissues take several weeks to adapt to corrective procedures. Relief comes only when shortened tissues have been elongated to the length necessary for pain-free function.

The Postural Syndrome.   The postural syndrome is characterized by mild to moderate soft-tissue strain with no or very minor pathology or gross structural distortion involved. It is the effect of mechanical deformation of soft tissues of the motion unit as the result of acute overactivity or prolonged postural stress that leads to pain.

Acute Lumbosacral Angle Syndromes

An acute lumbosacral angle is frequently associated with low back pain. In the erect position, the line of gravity should fall through the posterior edge of the lumbosacral joint. The average sacral angle during stance is about 40. The normal range appears to be between 3555, depending upon the reference used. Thus, function, alignment, and dynamic signs and symptoms are better criteria than exact angulation requirements.

The painful status of acute angulation of L5 on S1 is twofold:

(1) There is bursal involvement due to an overriding of the facets that stretches the bursa.

(2) There is a narrowing of the IVF, causing a telescoping of the facet joints from the superior to the inferior. Roentgenographically, the type of bursitis cannot be defined. Orthopedically, the problem is described as the facet syndrome. See Facet Syndromes in this chapter.

Roentgenographic evaluation is made by drawing a line through the superior border of the sacral base and through the inferior border of L5. If these lines cross within the IVF or anterior to it, this indicates a facet syndrome. Olsen recommends the use of Fergurson's angle, where the body of L3 is X'ed and a line is dropped perpendicular from the center of the vertebral body. This line normally falls over the sacral prominatory or the anterior edge of the sacrum and reveals normal lumbosacral weight bearing (Fergurson's line of gravity). The L5 disc spacing is seen normally as symmetrical with the one above, and the actual weight bearing is on the nucleus pulposus.

A persistent notochord may be seen in films where the disc is normal but embedded into the body of the vertebra. This is seen in a postural facet syndrome where the anterior disc space is wide at the expense of narrowed disc space posteriorly and the body of the vertebra has rocked on the nucleus. It is not pathologic. For example, a normal vertebra presents decreased disc space posteriorly with the lines crossing in the IVF. There is normal disc space anteriorly, but in order for this to happen, there is a herniation. The disc is normal, but the symmetry of the disc interspace is broken.

Disc Syndromes

It is generally agreed that a true diagnosis of disc herniation with or without fragmentation of the nucleus pulposus can only be made on surgical intervention. Thus, the term intervertebral disc syndrome is generally used when conservative diagnostic means are used exclusively.


Pathologic disc processes are rarely a specific entity. They invariably represent several superimposed processes, and atypical cases are numerous. A thorough case history, comprehensive physical examination, and appropriate roentgenographic and laboratory tests are always necessary to differentiate a sinister and sometimes subtle disease process from a mimicking biomechanical lesion. Static and dynamic inspection, palpation, percussion, sensory and reflex integrity, joint motion tests, motor evaluation, and peripheral vascular function tests must be meticulously conducted.


The IVD syndrome usually has a traumatic origin and occurs more commonly between the ages of 20 and 60. There may be a history of low back complaints with evidence of organic or structural disease. Most radicular involvement associated with a protruded disc occurs at the lower lumbar level. The L1L4 roots leave the cord below the disc level, and the L5 root usually cuts across both the L4 and L5 disc as it descends and the S1 root crosses the L5 disc. See Table 12.12.

     Table 12.12. Major Neurologic Signs in the Lumbosacral Radiculopathies

FeatureL3 Root L2L3 IVDL4 Root L3L4 IVDL5 Root L4L5 IVDS1 Root L5S1 IVD
Ankle reflexNormalNormalNormalDiminished
Back pain radiates to:Buttocks, dorsal thigh, anterior kneeButtocks, dorsal thigh, medial calfButtocks, lateral calf, dorsal foot, great toeButtocks, mid calf, plantar foot, heel
Lasegue's supine sign (SLR)Usually negative+ at 80 or more+ at 5060 or more+ at 3040 or more
Muscle weaknessQuadriceps femoris groupQuadriceps, iliopsoasGluteus med., ant. tibialis, hallucis ext.Gluteus max., hamstrings, gastrocnemius, soleus
Patellar reflexNormalDiminishedNormalNormal
Sensory signKnee numbnessLower medial leg numbnessNumbness at cleft between 1st and 2nd toe, dorsal footNumbness inferoposterior to lateral maleolus, heel, dorsal calf, lateral foot

A life-style with frequent flexion activities may cause the nucleus to migrate posteriorly, and the ability of the motion unit to fully extend will become restricted. The result is chronic stress on the posterior anulus and anterior disc thinning --leading to anular tears, posterior herniation, and anterior lipping. Once the posterior anulus becomes weakened by radial fissures, the disc will bulge both anteriorly and posteriorly during flexion. This causes extension to be further restricted to avoid stress upon the posterior extrusion of the anulus.

Anular and end plate tears lead to fragmentation, displacement, and the development of scar tissue. As the scar tissue contracts, the involved area of the disc becomes less elastic and the motion unit becomes less mobile. On repeated injury, the stiffened area fragments and the cycle repeats itself to an even more advanced state. Whenever a patient presents a history of recurring attacks with greater severity, adaptive changes can be assumed to have occurred.

While episodes of low back pain may be self-limiting within 46 weeks, they tend to recur and each successive attack tends to become progressively more severe.

     Table 12.13. Classes of Intervertebral Disc Syndromes

Grade IThe patient has intermittent pain and spasm with local tenderness. There is very little or no root compression. Paresthesia and/or radiculitis may extend to the ischial area.
Grade IISome nerve root compression exists along with pain, sensory disturbance, and occasionally some atrophy. Paresthesia and/or radiculitis may extend to the knee.
Grade IIIMarked demonstrable muscle weakness, pronounced atrophy, and intractable radicular pain. Paresthesia and/or radiculitis may extend to the ankle or foot.
Frank herniationComplete extrusion of the nucleus through the anulus into the canal or IVF. All above symptoms are found in herniation, and, in addition, pain is worse at night and not generally relieved by most conservative therapies.

Clinical Classes.   The terms protrusion, rupture, and herniation are often used interchangeably to describe the pathologic grade of an IVD lesion. However, to establish a practical guideline in the management of such lesions, many physicians refer to a Grade I, II, or III disc syndrome that is based primarily on symptomatology. See Table 12.13.

Relationship of Facet Planes to Disc Failure.   Studies by Farfan have shown a distinct correlation between the asymmetry of the facet planes and the level of disc pathology, as well as a correlation between the side of the more oblique facet and the side of sciatica. They show that the orientation of the lumbar articulation contributes to greater shear forces on the IVDs during axial rotation. These forces are especially increased at the L4 and L5 discs because of their angle from the horizontal plane. Such continued torsional loading readily predisposes failure of the anular fibers leading to disc disease.

Relationship of Sacroiliac Fixation to Disc Failure.   Sacroiliac fixation to any degree inhibits the compensatory torsion capacity of spinal segments. Illi's studies show that unilateral or bilateral sacroiliac subluxation predisposes lumbar disc pathology because once the sacroiliac mechanisms are disturbed, the normal dynamics of the lumbar spine overstress the IVDs, articular facets, and paravertebral soft tissues. Degeneration processes follow.


Episodic back pain is probably the only consistent symptom in IVD syndromes, and even this may not be present until the late stage. Disc pain is usually intermittent and mechanically aggravated by standing, lifting, coughing, prolonged flexion (eg, while shaving or stooping), or a slight misstep. Rothman/Simeone point out that for some unknown reasons these episodes often occur early in the day when nuclear turgor is at its maximum.

A unilateral sciatic pain following a specific dermatome and not remissive except by a possible position of relief is often manifested. There is usually a C scoliosis away from the side of pain, splinting, and a flattening of the lumbar spine. Lasegue's, Kemp's, and Naffziger's tests are positive. There may be diminished tendon reflexes of the involved segment and possible weakness and/or atrophy of the musculature innervated.

A disc protrusion initially impinges on the recurrent meningeal nerve in or just medial to the IVF, according to Wyke. At this stage, he feels that the centralized pain produced (without sciatica) is the result of pressure interrupting afferent mechanoreceptor activity and irritating the afferent nociceptive fibers. As the protrusion increases, impingement begins to involve the dorsal nerve roots and their dura sleeves, leading to increased pain extending more peripherally and the development of paresthesiae within the distribution of the sciatic nerve. The initially central pain in the midline spreads across the lumbosacral area, into the buttocks and thigh, and possibly as distal as the calf and heel as the lesion becomes worse.

Several investigators report that this process will reverse itself under corrective care; ie, progressively subsiding distally (retracing). This is believed to be an indication that reduction of the derangement is taking place, even when the pain appears to increase proximally as it subsides distally. The phenomenon of pain progressing from a central to a peripheral area as a patient's lesion worsens or retraces itself during correction seems to be limited to a disc derangement syndrome. It does not appear to be associated with postural or fixation syndromes.


The common indirect x-ray signs of disc degeneration are disc space narrow- ing, retrolisthesis, posterior subluxation, traction spurs, and facet degeneration. As a major adaptive change to the carrying of weight, there is normally a flattening of the lumbar lordosis and a mild rotation of the sacrum into a more vertical position. The maximum adaptation occurs at the lumbosacral junction with only minor adjustments at the higher levels. The L5 disc assumes a more nearly horizontal position with widening posteriorly and compression anteriorly, which results in a decrease in the downward sliding force (shear) applied at the S1 level. These comments by Olsen go on to state that the usual manifestation of disordered function of any part of the motion unit is weakness. He quotes DeJarnette that "the position of the sacral base is often compensatory to keep severe situations from becoming worse through weight bearing."

When an IVD leaves its normal anatomic position, routine radiographic examination without contrast medium may present diagnostic characteristics such as narrowing of the intervertebral space (most typical), retrolisthesis of the vertebral body superior to the herniated disc, posterior osteophytes on the side of the direction of the herniated disc or apophyseal arthrosis, and sclerosis of the vertebral plates as a result of stress on denuded bone (frequent). Such malformations as asymmetrical transitional lumbosacral vertebra and spina bifida occulta are seen more frequently with herniated disc than in cases in which these anomalies do not exist. Torsion is more common in the L4L5 disc than in the L5S1 disc.

Points to especially evaluate are asymmetry and unilateral elevation of disc spaces, limited and impaired mobility on the affected side, blocked mobility contralaterally one segment above the L5S1 level, and slight rotation of the L4 or L5 vertebral body toward the side of collapse. Abnormal findings suggesting a fixed prolapse in these functional views include flattening of the lumbar curve, posterior shifting of one or more lumbar vertebral bodies, impaired mobility on forward flexion so that the disc space does not change as compared to the findings in the neutral position, and impaired mobility on dorsiflexion.


During early disc degeneration, it is impossible to differentiate disc failure from other causes of backache such as instability or postural overstress. Sciatica is frequently absent during the early stage, but it may be elicited by a strong Valsalva maneuver. Many patients with chronic or recurring low back pain exhibit no evidence of a degenerative process, and many patients that display obvious signs of a degenerative process have no low back pain.

The first process to be ruled out should be pain from referred pelvic disease, primary or secondary neoplasm, metabolic diseases, and local infection.

Spinal neoplasms usually have their peak pain during sleeping hours. Infection invariably presents local bone tenderness as opposed to the soft-tissue tenderness of strain and sprain. The major differentiating clues are associated visceral signs and symptoms and paravertebral spasm in all directions.

After fracture, the first gross structural processes to be ruled out should be disc involvement, apophyseal involvement, ligament instability, spinal stenosis, spondylolisthesis, ankylosing arthritis, spinal osteoporosis, and hip pathology. Postural analysis, orthopedic evaluations, and neurologic tests are vital for accurate differentiation.

Spinal strain, sprain, and IVD herniation often resemble each other (see Table 12.14). In each, the onset of pain is usually sudden, activity is aggravating, mobility is diminished in the area involved, the normal lordosis is reduced, there are no signs of systemic disease, and x-ray and laboratory findings are usually negative. Also see descriptions of Sprains and Strains in this chapter.

     Table 12.14. Typical Signs of Disc Protrusion, Sprain, and Strain

FeatureDisc ProtrusionSprainStrain
Area of painConcave side of painConvex side of curveOver muscle
Curve patternSegmental distortionSegmental distortionAntalgic, if any
Deep pressure painOften bilateral, localized usually one jointUnilateral pain, localized, often one jointUsually bilateral, large area, in muscle
Effect of restRelieves painRelieves painStiffens area
Iliac positionLow on pain sideHigh on pain sideHigh on pain side
Initial feelingLockSnapTearing
Location of painSegmentLumbosacral or sacroiliac areaInvolved muscle
Major cause of painRoot/cord irritationSynovitisMyositis
Most painful actionHyperextension with torsionHyperextensionFlexion
Onset of painMinor traumaUnprepared jointDuring lifting
PercussionSharp pain that radiatesSharp local painLittle increased discomfort
Position of restStill positionStill positionMoves frequently


Kemp's Test.   While in a sitting position, the patient is supported by the examiner who reaches around the patient's shoulders and upper chest from behind. The patient is directed to lean forward to one side and then around to eventually bend obliquely backward by placing the palm on the buttock and sliding it down the back of the thigh and leg as far as possible. The maneuver is similar to that used in oblique cervical compression tests. If this compression causes or aggravates a pattern of radicular pain in the thigh and leg, the sign is positive and suggests nerve root compression. It may also indicate a strain or sprain and thus be present when the patient leans obliquely forward or at any point in motion. Not to be dismissed lightly would be the possibility of shortened contralateral paraspinal ligaments and tendons that would force erratic motion on the side of lateral flexion.

Since the elderly individual is less prone to an actual herniation of a disc due to lessened elasticity involved in the aging process, other reasons for nerve root compression are usually the cause. Degenerative joint disease, exostoses, inflammatory or fibrotic residues, narrowing from disc degeneration, and tumors --all must be considered.

Lasegue's Supine Straight-Leg-Raising Test.   The patient lies supine with legs extended. The examiner places one hand under the heel of the affected side and the other hand is placed on the knee to prevent the knee from bending. With the limb extended, the examiner most cautiously flexes the thigh on the pelvis to the point of pain, keeping the knee straight. The patient will normally be able to have the limb extended to almost 90 without pain. If this maneuver is markedly limited by pain, the test is positive and suggests sciatica from a disc lesion, lumbosacral or sacroiliac lesion, subluxation syndrome, tight hamstring, spondylolisthetic adhesion, IVF occlusion, or a similar disorder.

Some examiners feel that pain below 30 indicates sacroiliac involvement as there is no traction of the roots at the foraminal level in this range. Pain above 30 begins traction on the L5 root, and the more the leg is raised the greater tension is applied to the more cephalad roots. However, an extremely sensitive lumbar irritation will show signs quite early (eg, 30). Thus, all that can be specifically determined in this and similar tests is that pain is elicited at a certain point.

Many reports confirm that when Lasegue's sign is positive, the pupils will dilate, blood pressure will rise, and the pulse will become more rapid. However, these signs are not unique to low back pain. They are only helpful in that these phenomena are not present in the malingerer or psychoneurotic individual.

Lasegue's Rebound Test.   At the conclusion of a positive sign during Lasegue's supine straight-leg-raising test, the examiner may permit the leg to drop to a pillow without warning. If this rebound test causes a marked increase in pain and muscle spasm, then a disc involvement is said to be suspect. However, it would appear that any site of irritation in the lower back and pelvis would be aggravated by such a maneuver.

Lasegue's Standing Test.   Another method described by Lasegue is to have the patient attempt to touch the floor with the fingers while the knees are held in extension during the standing position. Under these conditions, the knee of the affected side will flex, the heel will slightly elevate, and the body will elevate more or less to the painful side. This would also be true with shortened posterior thigh and calf muscles.

Naffziger's Test.   This test essentially offers a suspicion of an abnormal space-occupying mass such as a spinal tumor or disc protrusion. It is performed by having the patient sit or recline while the examiner holds digital pressure over the jugular veins for 3045 seconds. The patient is then instructed to cough deeply. Pain following the distribution of a nerve may indicate nerve root compression. Though more commonly used for low back involvements, thoracic and cervical root compression may also be aggravated. Local pain in the spine does not positively indicate nerve compression; it may indicate the site of a strain, sprain, or another lesion. The sign is almost always positive in the presence of cord tumors, particularly spinal meningiomas. The resulting increased spinal fluid pressure above the tumor or disc protrusion causes the mass to compress or pull upon sensory structures to produce radicular pain. This test is contraindicated in geriatrics, and extreme care should be taken with anyone suspected of having atherosclerosis. In all cases, the patient should be alerted that jugular pressure may result in vertigo.

Facet Syndromes

It has been a popular belief that damage to the facet joint is always secondary to disc failure. However, Farfan, Grieve, and others state that autopsy evidence is clear that varying degrees of facet damage can and frequently do occur that are not secondary to disc failure. Helfet/Lee affirm that lesions of the posterior joints always have an effect on the disc, and disc lesions always have an effect on the posterior joints.

The subluxation of lumbar facet structures, states Howe, is a part of all lumbar dyskinesias and must be present if a motion unit is deranged. In a three-point articular arrangement, such as that present at each vertebral segment, no disrelationship can exist that does not derange two of the three articulations. Thus, determination of the integrity of or subluxation of the facets in any given motion unit is important in assessing that unit's status.


The facet syndrome can occur with:

(1) an anterior sacral base with a normal lordosis;
(2) an anterior sacral base with an accentuated lordosis;
(3) an anterior sacral base with a "sway back"; or
(4) a normal sacral base angle and the "sway back" type of individual.


The common cause of facet syndrome is not a weak back but a weak abdomen. When the healthy spine extends from flexion, the lumbar spine does not create its lordosis until near the upright position when body weight becomes centered on the discs. This is because the pelvis accommodates by rotating posteriorly. However, if the abdominals and/or hamstrings are weak, the lordosis begins to occur at about 45 to compensate for the abnormally increased sacral angle. This produces excessive stress at the lower lumbar facets, and the "catch" comes at this angle.

Cartilage is found between all articular surfaces, and undue stress during weight bearing on the facets can cause injury to the cartilage that will progress with degenerative changes. The degeneration may cause L5 to slip forward (degenerative disc disease), portray decreased disc space (discogenic disease), or exhibit decreased space with eburnation (discopathy). Sacralization is the only time when it is normal to have a decreased disc space, unless the disc is underdeveloped (hypoplasia). Along with the facet syndrome, there may also be an increased lordosis of the lumbar spine.


Any method of spinographic interpretation that utilizes strict millimetric measurements from any set of preselected points is most likely to be faulty because structural asymmetry and minor anomaly is universal in all vertebrae. However, the estimation of the integrity of facet joints is a reliable method of assessing the presence of intervertebral subluxation. An evaluation of the alignment of the articular processes comprising a facet joint may be difficult from the A-P view alone when the plane of the facet facing is other than sagittal or semisagittal. In this case, oblique views of the lumbosacral area are of great value in determining facet alignment since the joint plane and articular surfaces can nearly always be visualized.

When disrelationships of the facet articular structures cannot be visually identified, Howe suggests the use of Hadley's S curve. This is made by tracing a line along the undersurface of the transverse process at the superior and bringing it down the inferior articular surface. This line is joined by a line drawn upward from the base of the superior articular process of the inferior vertebrae of the lower edge of its articular surface. These lines should join to form a smooth S. If the S is broken, subluxation is indicated. This A-P procedure can also be used on an oblique view.


To help differentiate the low back and sciatic neuralgia of a facet syndrome from that of a protruding disc, several physical clues are available. For example, with the patient standing with his feet moderately apart, the doctor from behind the patient firmly wraps his arms around the patient's pelvis and firms his lateral thigh against the back of the patients' pelvis. The patient is asked to bend forward. If it is a facet involvement, the patient will feel relief. If it is a disc that is stressed, symptoms will be aggravated.

In facet involvement, the patient seeks to find relief by sitting with feet elevated and resting upon a stool, chair, or desk. In disc involvement, the patient keeps knees flexed and sits sideways in the chair and moves first to one side and then to the other for relief. If lumbosacral and sacroiliac pain migrates from one to the other side, it is suspected to be associated with arthritic changes.

Flank Pain

The general term flank pain refers to any pain perceived in the lateral lumbar area.


The complaint of flank pain automatically suggests a kidney disorder. However, various adrenal, colon, gallbladder, myofascial, spinal, and vascular etiologies must be excluded. See Table 12.15.

In either acute or chronic conditions and whether or not trauma is in the history, nephroptosis should not be overlooked. The various classes of nephroptosis are shown in Chapter 11, Table 11.42.


Fever, hematuria, mass, pyuria, and shock are the most significant symptoms in differential diagnosis. See Table 12.16.

     Table 12.16. Flank Pain and Associated Symptoms

Syndrome: Flank Pain +
Primary Suspect Disorders
HematuriaArterial embolism HypernephromaKidney stone
Renal tumor (invasive)
MassHip pointer
Perinephric abscess
Neurologic focal signsMyelitis Spinal cord tumorSubluxation complex
No other symptomsGallbladder disorder
Lumbar sprain
Lumbar strain
Urethral colic
Perinephric abscess
Vomiting and signs of impending shockAcute papillary necrosis
Arsenic poisoning
Arterial embolism
Colon rupture
Renal calculus
Toxic nephritis


Blood cultureEMGTuberculin test
CBC and differentialG-I seriesUrinalysis
Chest x-raySedimentation rateUrine culture
ECGSpinal RoentgenographyVD serology


The term lumbago refers to a dull, aching, generalized pain in the lumbar region. Popular use restricts it to pain of neuromusculoskeletal origin rather than of visceral disease; eg, minor subluxation syndromes, myofibrositis, lumbar sprain or strain, and trigger-point syndromes.

The most common trigger points causing lumbar pain are found in the longissimus thoracis, multifidi, and rectus abdominis. Less frequently, the iliocostalis lumborum or thoracis may be the site.

Lumbosacral Instability

Lumbosacral instability is a mechanical aberration of the spine that renders it more susceptible to fatigue and/or subsequent trauma by reason of the variance from the optimal structural weight-bearing capabilities. It is the most common finding of lumbosacral roentgenography and often brought to light after a vigorous strain. Primary instability of the lumbar spine is considered to be a common cause of low back pain, due to the loss of soft-tissue integrity leading to diminished intersegmental control, weakness, and liability to yield under normal stress and produce abnormal articular sliding (subluxation).


As each spinal segment rests upon the one beneath it and the interposed joint surfaces serve as the support base of the separate segments, the force of gravity acting upon each segment must be individually neutralized if the body as a whole is to be in complete gravitational balance. Thus, joint stability is partially dependent on:

(1) the size of the joint surfaces,
(2) the height of the segmental centers of gravity above the joint surface, and
(3) the horizontal distance of the common gravity line to the joint's center.

In the adult lumbar spine, the interspinous and supraspinous ligaments play a minimal role in segmental stability. White/Panjabi report that these ligaments are frequently absent, degenerated, or ruptured.


Instability may be the result of rotation with or without much tilting, flexion with or without much rotation, lateral displacement (rare without fracture), lateral tilt and wedging, or extension overstress with or without spinous process impingement. The most common level involved is at the L4L5 interfaces (90%). Harriman states that between 50% and 80% of the general population exhibit some degree of the factors that predispose to instability whether by reason of anomalous development of articular relationships or altered relationships due to trauma or disease consequences.

The cause of lumbosacral instability is frequently traumatic, which is frequently repetitive microtrauma. The results are most often seen in middle-aged males. Frequent trauma to the articular structures as a result of excessive joint motility results in repetitive, low force injury. The scope of involvement and the tissue response are determined by the type and severity of the instability.


A disturbed physiologic response of the spinal motor unit is the primary finding, along with the sequela of a "stress response syndrome" that may take the form of any degree between sclerosis of a tendon to and including an ankylosing hypertrophic osteophytosis or arthrosis. Unusual early fatigue is a constant symptom, and chronic exhaustion leads to strain, sprain, and subsequent disc pathologies. Symptom susceptibility increases with the age of the individual. Postural evaluation is especially important in the physical diagnosis of the sequelae as well as to an extra-spinal causation (eg, an anatomic short leg).

Painful attacks with severe splinting, often with brief episodes of paresis and paresthesiae, are usually sudden in onset and frequently bilateral as opposed to the unilateral pain of a posterolateral disc protrusion. The paravertebral ligaments are extremely tender, and pain is increased by rotation. Neurologic signs and Lasegue's tests are usually negative. In most cases, the acute attacks of instability are quickly relieved by rest and support.


Roentgen diagnosis is the only sure manner of delineating the type and everity of the underlying productive agent of instability. There are no unique findings except the recognition of the complex of the various anomalies and pathologies present. Care should be taken to include the entire pelvis in this determination as, for instance, a sacroiliac arthrosis may lead to lumbar instability.


Once the difference between normal and abnormal muscle function is well understood, changes in posture, muscle tone, and movement offer fundamental clinical clues to diagnosis and therapy. If the biomechanical mechanisms involved are appreciated, painful effects can often be reproduced or relieved at will.

Knowing exactly where, when, and how motion increases or decreases pain are the major clues that lead the examiner to find and correct the biomechanical fault whether it be functional or structural.


Watching the body move offers the best clues to muscle trouble. If a posterior disc protrusion or an irritated nerve root is involved, the patient will invariably assume an antalgic position. The posteriorly rotated pelvis, the flattened lumbar area, and the slight flexion of the knees and hips, bilateral or unilateral, are unconscious attempts to lessen the tension of the involved sciatic nerve and/or to reduce intradisc pressure. The greater the pain, the greater will be this "semi-squatting" posture in the upright position. Golfers will recognize this position of balance.

General spasm of the spinal muscles guarding motion in the vertebral joints can be tested by watching the body attitude (eg, stiff, military carriage) and by efforts to bend the spine forward, backward, and to the sides. If the examiner is familiar with the average range of mobility in each direction and at the different ages, this test is usually easy and rapid. Care should be taken to differentiate phasic spasm (usually antalgic) from frequently exhibited reflex hypertonicity.

It is one thing to find muscle spasm present and another to determine if it is protective, compensatory, hysterical, or a causative factor. Careful analysis of gait is an important method of gaining differential clues. Limitations of motion due to muscular spasm are seen with special frequency in joint pathology and subluxation-fixations, but they may occur in almost any form of joint trouble, particularly in the larger joints.


Muscle Pain from Overexertion. Many acute spinal pains with a history of overexertion are muscular in origin. There are two types of postexertion pain of muscular origin: immediate pain and delayed pain. They may be found most anywhere in the body but are more common to the lumbar area. See Chapter 2, Myalgia and Tenalgia.

The overexertion syndrome may be from:

(1) continuous contractions of long duration in a normal physiologic state,
(2) vigorous jerky movements of short duration, or
(3) a combination of stretch reflex and relaxation reactions if fibers have been stretched to a pathologic length. It has been shown that repeated stress can produce more soreness if a short rest interval is allowed between movements (eg, shoveling).

Muscular Pain from Lymph Dysfunction.   Myalgia of muscle and lymph etiologies are often combined. Although skeletal muscle tissue lacks an intrinsic lymph supply, a muscle's connective tissue sheath and tendons are richly endowed with lymphatic vessels. During the normal physiologic exchange of fluids through capillary walls, the quantity of fluid leaving the capillary is usually greater than that entering the venule. The related lymphatic network takes up this excess and eventually delivers it to the venous system. It is this process that allows a continuous exchange of tissue fluids and maintains a constant interstitial fluid pressure.

The flow of lymph is increased during activity as is capillary circulation, but this flow can be restricted by excessive pressure exerted by a constantly hypertonic or phasic contracted muscle. De Sterno shows that inhibited lymph drainage contributes to muscular pain during prolonged activity by:

(1) causing a buildup of interstitial fluids that increase hydrostatic pressure and
(2) encouraging the accumulation of metabolic waste products that would normally be drained by the lymphatics and venules.

Nerve Root Lesions.   Nerve function disturbances associated with subluxation syndromes and specific diseases manifest as abnormalities in sensory interpretations and/or motor activities. Disturbances related to subluxation syndromes may be through one of two primary mechanisms: direct nerve or nerve root disorders, or of a reflex nature.


Nerve Entrapment or Irritation.   See Chapter 2, Vertebral Subluxation Syndromes. Disc syndromes and Sciatica are described separately in this chapter. Pelvic nerve entrapment syndromes are described in Chapter 13.

Root Traction.   Peripheral nerves have considerable tensile strength against stretch, but nerve roots do not. Thus, excessive traction forces can create considerable stress, dural leaks, etc. Traction (tension) on the root can pull the IVF contents outward, subjecting the thicker intracanal portion of the root complex to adverse pressure and irritation.


The major neurologic signs found in lumbosacral radiculopathies are listed in Table 12.12, and points in differentiating nerve lesions from root or cord lesions are presented in Table 12.17.

     Table 12.17. Differentiation of Nerve, Root, and Cord Lesions

Nerve LesionsCaudal-Root LesionsLumbosacral Cord Lesions
Fibrillation in muscles absent or slightSameFibrillation of muscles active
Muscle atrophy and reaction of degeneration may be presentSameSame
No loss of sexual powerOften some loss of sexual powerSexual power lost or impaired
Pain often aggravated by movement, but spontaneous pain not severeSpontaneous pain is often severe; movement of limbs not painful; coughing, sneezing are painfulPain absent unless nerve roots are implicated
Pain on pressure over nerve trunks commonNot present; superficial hyperalgesia or anesthesia dolorosaNot present
Reflexes lost in areas affected; others are not increasedSameAchilles reflex may be absent and patellar increased or vice versa, or all reflexes may be lost
Seldom involve dorsal divisions of peripheral nervesInvolve both dorsal and ventral distributionsInvolve both dorsal and ventral distributions
Sensory loss involves pain, touch, temperatureSameSensory dissociation may be present with unilateral lesions in upper lumbar segments
Sphincters not affectedSphincters may be affectedSphincters usually affected
Symptoms present in nerve distributionSymptoms in segmental distributionSymptoms in segmental distribution
Trophic sores absentTrophic sores unusual or mildTrophic sores common and severe
Usually unilateralUsually bilateral, but not symmetricalUsually bilateral and symmetrical
X-ray negativeX-ray may show pathology below L1 (fracture, dislocation, cariesX-rays may show some pathol-ogy in T11, T12, or L1

Lower Extremity Atrophy.   Prolonged and/or severe nerve root irritation may show evidence of trophic changes in the tissues supplied. This may be characterized by obvious atrophy. Such a sign is particularly objective when the circumference of an involved limb is measured at the greatest girth in the initial stage and this value is compared to measurements taken in later stages. Chronic L5 root compression exhibits weak dorsiflexion of the foot, characterized by a slapping foot drop during gait. In contrast, chronic L4 root compression manifests weak quadriceps associated with knee pain and buckling during stance. Many knee operations have been unsuccessful because the focal irritation was of the L4 root rather than in the knee.

Pain from Disc Protrusion.   If the protrusion is lateral to the nerve root, the patient will lean laterally away from the side of lesion and the sciatic pain. If the protrusion is medial to the nerve root, the list of the trunk will be toward the side of the lesion and the sciatica.

Referred Pain.   Root pain usually has a dermatomal distribution that is aggravated by a Valsalva maneuver. In contrast, abnormal stimuli arising from the lumbar paravertebral soft tissues often refer a dull, diffuse, sclerotomal ache to the sacroiliac joints, buttocks, or posterior thighs. The term sclerotome refers to tissues with the same embryonic origin. The pain may be solely sclerodermal or it may be superimposed on dermatomal radicular pain and greatly confuse the clinical picture. It may originate from numerous sources.

Poole lists the subcutaneous tissues overlying the motion unit, the posterior aspect of the disc, the dura mater and epidural adipose tissue, the adventitial sheaths of the epidural and paravertebral veins, the walls of the vertebral arteries and arterioles, the articular capsules, the longitudinal ligaments, the ligamentum flavum, the interspinous ligaments, the paravertebral muscles and their tendons, and the periosteum.

Sensory Changes.   The posterior sensory root in the lumbar spine is twice the thickness of the anterior motor root. When direct nerve root involvement occurs on the posterior root of a specific neuromere, it manifests as an increase or decrease in awareness over the dermatome; ie, the superficial skin area supplied by this segment. Typical examples might include foraminal occlusion or irritating factors exhibited clinically as hyperesthesia, particularly on the:
(1) anterolateral aspects of the leg, medial foot, and great toe, when involvement occurs between L4 and L5; and
(2) posterolateral aspect of the lower leg and lateral foot and toes when involvement occurs between L5 and S1.

In other instances, this nerve root involvement may cause hypertonicity and deep pain in the musculature supplied by the neuromere; for example, L4 and L5 involvement, with deep pain or cramping sensations in the buttock, posterior thigh and calf, or anterior tibial musculature. In addition, direct pressure over the nerve root or distribution may be particularly painful.

Spinosomatic Reflexes.   Nerve root insults from subluxations may be evident as disturbances in motor reflexes and/or infrequently as loss of muscular strength. Examples of these reflexes include the deep tendon reflexes such as seen in reduced patella and Achilles tendon reflexes when involvement occurs at L2L4 or L5S2, respectively. These reflexes should be compared bilaterally to judge whether the hyporeflexia is unilateral. Unilateral hyperreflexia is highly indicative of an upper motor neuron lesion.


Kemp's, Lasegue's, and Naffziger's tests have been previously described in this chapter (Disc Syndromes), and other orthopedic and neurologic tests will be summarized below as as aid in differentiation. An examiner should keep in mind that the originators made specific claims of the significance of these tests, but the projected findings and conclusions are not duplicated consistently in practice.

Wyke has shown that because the nociceptive receptor system of the lumbar spine has such an extensive distribution, testing procedures designed to selectively stress individual components and segments by orthopedic stress tests are extremely difficult if not impossible to perform. Only by visualizing the structures being affected and the biomechanical forces being applied will such tests be meaningful to the examiner.

Bragard's Test.   If Lasegue's supine test is positive at a given point, the leg is lowered below this point and dorsiflexion of the foot is induced. The test is negative if pain is not increased. A positive sign is a finding in sciatic neuritis, spinal cord tumors, IVD lesions, and spinal nerve irritations, but certainly not limited to these disorders. Tight calf muscles and hamstrings would also resist dorsiflexion. Several authorities state that Bragard's test helps to differentiate the pain of sciatic involvement from that of sacroiliac involvement as the sacroiliac articulation is not stressed by the Bragard maneuver, nor is the lumbosacral joint. However, the sacroiliac joint would be stressed if the calf muscles and hamstrings have shortened because the ilium would be pulled posterior if the limb is raised to any significant degree.

Demianoff's Test.   This is a variant of Lasegue's supine test used by many in lumbago and IVF funiculitis, with the intent of differentiating between lumbago nd sciatica. When the affected limb is first extended and then flexed at the hip, the corresponding half of the body becomes lowered and with it the muscle fibers fixed to the lumbosacral segment. This act, which stretches the muscles, can induce sharp lumbar pain. Lasegue's sign is thus negative as the pain is caused by stretching the affected muscles at the posterior portion of the pelvis rather than stretching the sciatic nerve. To accomplish this test with the patient supine, the pelvis is fixed by the examiner's hand firmly placed on the ASIS, and the other hand elevates the leg on the same side. No pain results when the leg is raised to an 80 angle. When lumbago and sciatica are coexistent, Demianoff's sign is negative on the affected side but positive on the opposite side unless the pelvis is fixed. The sign is also negative in bilateral sciatica with lumbago. The fixation of the pelvis prevents stretching the sciatic nerve, and any undue pain experienced is usually associated with ischiotrochanteric groove adhesions or soft-tissue shortening.

Deyelle-May Test.   This test may be helpful in differentiating the various etiologies of sciatic pain and is particularly designed to differentiate between pain from pressure on the nerve or its roots and pain due to other mechanisms in the lower back. Compression or tractional pressure on muscles, ligaments, tendons, or bursae may cause reflex pain that often mimics actual direct nerve irritation. Reflex pain does not usually follow the pattern of a specific nerve root. It is more vague, does not cause sensory disturbances in the skin, comes and goes, but may be a very intense ache. The procedure in the sitting position is to instruct the patient to sit very still and brace the trunk in a chair with the hands. The painful leg is passively extended until it causes pain, then lowered just below this point. The leg is then held by the examiner's knees and deep palpation is applied to the sciatic nerve high in the popliteal space which has been made taut (bow string) by the maneuver. Severe pain on palpation indicates definite sciatic irritation or a root compression syndrome as opposed to other causes of back and leg pain such as the stretching of strained muscles and tendons or the movements of sprained articulations.

Fajersztajn's Sign.   When Lasegue's straight leg raising and dorsiflexion of the foot (Bragard's test) are performed on the asymptomatic side of a sciatic patient and this causes pain on the symptomatic side, there is a positive Fajersztajn's sign that is said to be particularly indicative of a sciatic nerve root involvement such as from a disc syndrome, dural root sleeve adhesions, or some other space-occupying lesion. This is sometimes called the cross-leg straight-leg-raising test. From a biomechanical viewpoint, this test would be suggestive and not indicative.

Reiter's Syndrome

The triad of sterile spondylitis, uveitis, and prostatitis is called Reiter's Syndrome. The cause is unknown. Backache is usually the presenting symptom, but urinary or conjunctival complaints may manifest first. The weight-bearing joints show the first arthritic changes, and later the proximal joints of the fingers and toes become afflicted.

In differentiation from ankylosing spondylitis, it is well to mention here that about one in four patients with ankylosing spondylitis will present a degree of iritis. Reiter's syndrome also has its highest incidence among males 2040 years of age. While associated sacroiliitis is common, progression to spondylitis never occurs early in the disease process.

Sacroiliac Pathology

The sacroiliac joint in most cases may be only a small part of the systemic picture of a widespread disease process, yet it may be an early focal site. The clinical profiles of pelvic tuberculosis, cancer, Paget's disease, osteoarthritis, rheumatoid arthritis, gout, and the various metabolic and immunologic bone diseases have been previously described.


Serious visceral pathology and hernias often simulate musculoskeletal dysfunction. It is unexplained why leukemia and other systemic diseases may present only backache as the presenting symptom, but it does occur. Back pain often arises early in visceral disease, long before classic physical signs and hematologic changes are noted. A few pathologies may extend from or affect the sacroiliac joints early that often mimic the symptoms of sprain or chronic subluxation. Confusion may exist when related symptoms are brought out after trauma.


Almost any type of bacterial infection may originate in or extend to the sacroiliac joints. Tuberculosis is the first suspicion. The highest incidence is in children regardless of the type of infection. As the sacroiliac lesion is usually painless, diagnosis must be made by laboratory, roentgenographic, and thermographic evidence when the classical signs of infection arise. Fever and a high sedimentation rate are invariably present. Infrequently, an abscess may appear early. Differentiation must be made from septic arthritis and Ewing's sarcoma.


Although it is the largest nerve of the body and supplies through its branches all the muscles below the knee, the sciatic nerve is rarely injured by sudden trauma. It is often affected, however, by sciatic neuritis (sciatica) that is frequently due to intermittent intrinsic trauma.


Sciatic neuralgia or neuritis is characterized by pain of variable intensity to a maximum that is almost unbearable. The pain radiates from the lumbosacral or sacroiliac area down the posterior thigh and even to the sole of the foot. In time, muscular atrophy and a characteristic limp are usually present.

The comparative height of the iliac crests should be noted. If chronic sciatic neuralgia is on the high iliac crest side, degenerative disc weakening with posterolateral protrusion should be suspected. If occurring on the side of the low iliac crest, one should first consider the possibility of a sacroiliac slip and lumbosacral torsion as being the causative factor.

There is a lessening or lack of the patellar tendon reflex in sciatica (Babinski's sciatica sign). When the patient's great toe on the affected side is flexed, pain will often be experienced in the gluteal region (Turny's sign). Also in sciatica, the pelvis tends to maintain a horizontal position despite any induced degree of scoliosis (Vanzetti's sign), unlike other conditions in which scoliosis occurs where the pelvis is tilted.


Sciatic neuropathy must be differentiated from a lumbar impingement radiculopathy, and this is often challenging. The latter can be considered a nerve compression syndrome. As disc herniation rarely involves several segments, neuropathy is first suspected when multiple segments are involved.

In contrast to forward flexion in the standing position, flexion in the supine position places little tension on the sciatic nerve. Thus, sciatica that is aggravated by both standing and supine flexion suggests a disc involvement. Sciatica that is aggravated in the standing but not the supine position suggests a nerve root involvement.

When Lasegue's straight-leg-raising test is made just short of pain, internal rotation of the femur increases pain and external rotation decreases pain in sciatic neuropathy but has little effect upon lumbar radiculopathies. During Lasegue's supine test, sciatic pain is almost always increased by forced dorsiflexion of the foot and relieved by flexion of the knee. As the point of pain is reached, active flexion of the patient's neck will increase pain in radicular involvement because of the increased tension on the dura. This test is considered a positive Lasegue confirmation, but it does not pinpoint the exact site of the lesion.


The three major forms of spondylitis are ankylosing spondylitis, spondylitis associated with bowel disease, and spondylitis associated with psoriasis.


Ankylosing spondylitis closely resembles spinal rheumatoid arthritis. The latex fixation test is rarely positive in ankylosing spondylitis, but the HLA W27 leukocyte antigen is present in 90% of cases according to Macnab. The disorder often has a genetic history, and the incidence is highest among males 2040 years of age. Progression to complete or widespread involvement is unpredictable.

The sacroiliac joint is the site of the focal lesion in about 80% of cases, with "blurred" sacroiliac joints appearing early in roentgenography. Extension is then made to the costovertebral and manubriosternal joints, and this will exhibit a decrease in normal chest expansion on forced inhalation.

Clinical tests will elicit signs of sacroiliitis and rigidity of the lumbar and later the thoracic spine during forward flexion. Later, inflammatory destruction will exhibit widening of the sacroiliac joint space, sclerosis, squaring of the involved vertebral bodies, and anular and paravertebral ossification. When the disorder becomes widespread after several years, cardiovascular and pulmonary symptoms manifest.


Acute spondylitis is sometimes related to ulcerative colitis and Crohn's disease (regional enteritis). Sacroiliac symptoms may appear even before the visceral symptoms, and the joint sacroiliitis may continue to progress after the bowel symptoms subside.


The incidence of psoriatic arthritis is highest in women 2040 years of age. Psoriatic arthritis may attack the lumbar spine and sacroiliac joints almost simultaneously, but few psoriatic patients with backache are victims of spondylitis. It must be kept in mind that a psoriatic patient is subject to the same lumbar and pelvic musculoskeletal dysfunctions as any nonpsoriatic individual. Thus, the examiner should not suspect psoriatic arthritis just because of the presence of the classic skin lesions.


Tenderness is frequently found at the apices of spinal curves and rotations and not infrequently where one curve merges with another. Tenderness about spinous or transverse processes is usually of low intensity and suggests articular strain. Tenderness noted at the points of nerve exit from the spine and continuing in the pathway of the peripheral division of the nerves is a valuable aid in spinal analysis; however, the lack of tenderness is not a clear indication of lack of spinal dysfunction. Tenderness is a subjective symptom influenced by many individual structural, functional, and psychologic factors that often make it an unreliable sign.

Thoracolumbar and Lumbosacral Trigger Points

The most common trigger points for the lumbar area are located:

(1) alongside the T12L1 spinous processes and
(2) alongside the L5S1 spinous processes.

The T12L1 trigger, often associated with a T12 spinous tipped posterosuperior, frequently refers pain to the iliac crest with secondary nodules found deep along the posterosuperior crest. The L5S1 trigger is usually within the multifidi. Trigger points may also be found in the erector spinae, when the patient is prone, about 1 inch lateral to the spinous processes. See Table 12.18.

     Table 12.18.   Major Trigger Points Causing Low Back Pain

Area of Perceived Pain
Primary Suspect Muscles
Low thoracic areaIliocostalis thoracisRectus abdominis
  Longissimus thoracisSerratus posterior inferior
Lumbar painIliocostalis lumborumPsoas major
  Longissimus thoracisPsoas minor
  MultifidiRectus abdominis
Sacral and gluteal painLongissimus thoracisPubic pyramidalis
  MultifidiQuadratus lumborum


The articulations of the lower back are located fairly central to the kinematic chain extending from the cranium to the feet. Thus, any alteration in normal dynamics such as a unilateral fixation must manifest biomechanic effects both above and below. Fixation at a link or links of any kinematic chain forces hypermobility and aberrant movements on the nearest possible segments.

Lumbar Subluxations

The apices of curvatures and rotations are logical points for spinal listings since they are frequently the location of maximum vertebral stress. Subluxations may occur at other points in curves and rotations, particularly at the beginning point of a primary defect in balance such as in the lower lumbar and upper cervical sections. Subluxations also frequently occur at the point where a primary curve merges into its compensatory curve. A posterior L3 is rare when the apex of the lumbar curve is too high or too low, but posteriority is common at L4, L5, or the sacral base. When the apex of the lumbar curve is too low, a posterior subluxation will most likely be found in the upper lumbar area.

Rotational malpositions of the lower lumbar vertebrae are frequently found and invariably associated with changes in the related disc and posterior joints. In addition, rotation is coupled with tilting and vice versa. It is usually impossible to tell what is primary and what is secondary as each can cause the other. Periodic recurrence after correction can usually be attributed to congenital asymmetry of the facet planes or acquired asymmetry from the repeated deformation forces of trauma.

See Nerve Root Lesions in this chapter.

Lumbar Ligament and Muscle Fixations

Whenever a vertebral motion segment is in a state of prolonged distortion, the involved connective tissues histologically adapt to their biomechanical requirements. Fibers on the side of the concavity shorten, and fibers on the side of the convexity lengthen. This process occurs in all connective tissues but becomes more overt in muscular and ligamentous tissues because motion is no longer symmetrical. Unless corrective action is taken, this state becomes progressively degenerative as the result of the abnormal weight distribution during static and dynamic activity.

While 15% of asymptomatic patients indicate hypomobility of the lumbar region, a recent study has shown that as many as 43% of patients with low back pain have decreased movement of the lumbar spine.

The Erector Spinae. When these muscles become fibrotic, gentle and progressive stretching is required, often for many months because they are largely fascia to begin with. Due to their placement bilaterally, the most helpful exercise is lateral bending in the standing position as A-P motions may overexert the lower lumbar area.

The Iliolumbar Ligaments.   Functionally, L5 acts as part of the pelvis. This is probably due to the usually strong iliolumbar ligaments that connect the L5 ransverse processes to the iliac crests. Aside from the articular facets, the iliolumbar ligaments are the most important structures limiting axial rotation of L5 on the sacrum and preventing forward gliding of L5 on the sacrum.

The Interspinous Muscles.   Chronic hypertonicity of the lumbar interspinous muscles leading to fibrotic changes is probably the most common finding associated with the fixed lordosis that is related to chronic low-back pain. Such a lordosis does not fully flatten in the supine position. The focal superior articulation is pulled into a stressed position away from the inferior process (facet syndrome). On a lateral roentgenograph, the involved articular space exhibits an abnormal V-shaped appearance and the disc space will appear increased at the anterior and decreased at the posterior. In the more acute stage, it is due strictly to muscular spasm. In the chronic stage, the muscles become fibrotic and the paravertebral ligaments shorten, often to an area extended quite lateral from the midline.

The Intertransverse Muscles.   Chronic hypertonicity of the intertransverse muscles is another common cause of low-back pain. The transverse processes approximate, the disc thins ipsilaterally, and the height of the IVF is reduced. In contrast to quadratus lumborum fixation, stiffening of this muscle leads to sciatica on the concave side of the lumbar scoliosis.

The Quadratus Lumborum.   This quadrate muscle, which acts as one large muscle on each side of loin, connects the iliac crest and thoracolumbar fascia to the 12th rib and transverse processes of the lumbar vertebrae. Its primary role is that of lumbar lateral flexion and rotation during lateral flexion of the trunk. When active bilaterally, it stabilizes the lumbar spine. If involved in either local or reflex hypertonicity, the posterior lumbar articulations on the side of fixation are forced open in an abnormal arc. If severe, this can force the inferior process into the IVF and produce direct impingement of the IVF contents. The typical result is sciatica on the convex side of the lumbar scoliosis.

When lumbar and pelvic muscles become fibrotic, a search should be made for other areas within the lower extremity such as in the hip flexors and the gastrocnemius (eg, the "high heel" syndrome).

Sacroiliac Subluxations

Many authorities state that the sacrum and pelvis can be considered a biomechanical unit where rocking of the pelvis is accompanied solely by a change in the sacral angle. Cineroentgenography shows that this is true only when the sacroiliac and pubic articulations are completely fixated in all directions of movement. Cineroentgenographic studies of the sacroiliac joint have also shown that sacroiliac movement is highly variable and patterns of movement difficulties differ widely from patient to patient. These patterns are often attributed to differences in lateral sacral or iliac dimensions, articular variances, calcified ligaments, unusual pelvic designs, and oddities at the lumbosacral articulation.


Sacroiliac subluxations produce:

(1) irritative microtrauma to the interarticular structures,
(2) induction of a vertebral motion unit subluxation and/or contributions to the chronicity of subluxations,
(3) induction of spinal curvatures and/or contributions to the chronicity of existing curvatures, and
(4) biomechanical impropriety of the pelvis in static postural accommodation and locomotion.

Local pain and acute tenderness are rarely seen in chronic cases unless the ixated site is irritated by trauma. Old lesions appear to enjoy confusing the examiner by referring signs and symptoms far above or below. Roentgenography is quite helpful, but rarely is it an end in itself. Thus, immobility, stress tests, and spinal balance are the most reliable clues.


The most common errors of analysis stem from misleading visual signs, subjective responses to testing procedures, structural symmetry, and subjective descriptions of pain.

Several authorities state that sacroiliac pain will always be on the side of hypermobility, while others of equal credentials place the pain on the side of fixation. Some state that the side of fixation is always the major, while others say that the side of hypermobility is always the major because the joint is normally hypomobile. This confuses everybody except the mentor's disciples. It is this author's opinion that the typical pain of sacroiliac stress is diffuse across the sacroiliac area and most difficult for the patient to isolate. It is not uncommon for referred pain to detour from textbook descriptions (eg, gallbladder distress does not always refer to the right scapula, anginal pain does not always refer to the left arm). Even palpable tenderness may be referred. The most reliable clues are the site of consistently increased pain on biomechanical stress tests and, conversely, opposite maneuvers that relieve pain, tenderness, and structural imbalance. When dealing with individual patients, each of which is unique, the doctor is best directed by what he or she finds to be true in the situation at hand and not on the theories of others based upon their patients.

Piedallu's Sign.   When a sacral base is subluxated unilaterally anteroinferior and lateral so that the adjacent ilium is subluxated posteroinferior and medial, the ipsilateral PSIS on the side of inferiority will be low in the standing and sitting positions. If this PSIS becomes higher than the contralateral PSIS during forward flexion, the phenomenon is called a positive Piedallu's sign. Such a sign signifies either ipsilateral sacroiliac locking where the sacrum and ilium move as a whole or muscular contraction that prevents motion of the sacrum on the ilium. Regardless, it shows that sacroiliac dysfunction is probably present.

Visual Signs in Acute Cases.   Any severe sprain or strain will produce reflex muscle splinting as a protective mechanism. This spasm around any joint will not release until the neuron excitation subsides. A basic clue of an antalgic posture associated with lumbar or pelvic dysfunction is the head far removed from the midline when viewed from the A-P --much farther lateral than that seen in uncompensated or decompensated scolioses. The pelvis will often be severely tilted and twisted with the spine torqued in several opposite directions above ("corkscrew" reaction). The trunk will usually be flexed in the basic protective position. Thus, pain and splinting produce temporary antalgic postures that invariably mask and sometimes reverse basic distortions, rendering visual analysis of basic balance patterns useless at the time. While antalgic postures have a predictable pattern with each individual, they vary widely from patient to patient because of uniquely acquired conditioned reflexes, different pain thresholds, and the stage of related inflammation.


To differentiate sacroiliac from lumbosacral disorders, the patient is placed supine on a firm flat table. A folded towel is placed transversely under the small of the patient's back. The doctor stabilizes the patient's pelvis by cupping his hands over the ASISs and exerting moderate pressure. The patient is instructed to raise both extremities simultaneously with the legs straight. If the patient senses discomfort or an increase of discomfort in the low back or over the sacrum and gluteal area at about 2550 leg raise and before the small of the back wedges against the towel, sacroiliac involvement can be suspected. If, on the other hand, discomfort is experienced or augmented only after the legs have been raised beyond 50 and the small of the back wedges firmly against the towel, lumbosacral involvement should be the first suspicion.


Belt Test.   The standing male patient flexes forward with the examiner hold- ing the patient's belt at the back. If bending over without support is more painful than with support, it suggests a sacroiliac lesion. Conversely, if bending over with support is more painful than without support, it suggests a lumbosacral or lumbar involvement.

Berry's Sign.   If backache is relieved when the patient goes from a standing to sitting position, such relief is said to be indicative of a pelvic lesion rather than a lumbar condition. This relief, a positive Berry's sign, comes from hamstring relaxation.

Erichsen's Pelvic Rock Test.   With the patient supine, the examiner places his hands on the iliac crests with his thumbs on the ASISs and forcibly compresses the anterior pelvis toward the midline. This tends to separate the sacroiliac joints. If conducted carefully, this test can be quite specific. Pain experienced in a sacroiliac joint suggests a joint lesion that may be postural, traumatic, or infectious in origin.

Gaenslen's Test.   In this test, the patient is placed supine with knees, thighs, and legs acutely flexed by the patient who clasps the knees with both hands and pulls them toward the abdomen. This brings the lumbar spine firmly in contact with the table and fixes both the pelvis and lumbar spine. With the examiner standing at right angles to the patient, the patient is brought well to the side of the table and the examiner slowly hyperextends the opposite thigh by gradually increasing force by pressure of one hand on top of the knee while the examiner's other hand is on the flexed knee for support in fixing the lumbar spine and pelvis. Some examiners allow the hyperextended limb to fall from the table edge. The hyperextension of the hip exerts a rotating force on the corresponding half of the pelvis. The pull is made on the ilium through the Y ligament and the muscles attached to the anterior iliac spines. The test is positive if the thigh is hyperextended and pain is felt in the sacroiliac area or referred down the thigh, providing that the opposite sacroiliac joint is normal and the sacrum moves as a unit with the side of the pelvis opposite to that being tested. It should be tested bilaterally. A positive sign may be elicited in a sacroiliac, hip, or lower lumbar nerve root lesion. If the L4 is involved, pain is usually referred anteriorly to the groin or upper thigh. If the sign is negative, a lumbosacral lesion should be suspected. This test is usually contraindicated in the elderly.

Hibb's Test.   With the patient supine, the examiner extends the patient's thigh on the affected side and rotates the hip joint internally by rotating the leg at the knee. An increase in pain is a positive indication of a sacroiliac lesion if the possibility of a hip lesion has been eliminated.

Iliac Compression Test.   The patient is placed on his side with the affected side up. The examiner places his forearm over the iliac crest and leans pressure downward for about 30 seconds. This tends to compress the sacroiliac and pubic joints. A positive sign of joint inflammation or sprain is seen with an increase in pain; however, absence of pain does not necessarily rule out chronic sacroiliac involvement. This test is usually contraindicated in geriatrics and pediatrics or with any sign of a hip lesion or osseous pelvic pathology.

Mennell's Test.   The patient is placed prone, and one hand is used to stabilize the contralateral pelvis. With the palpating hand, the examiner places a thumb over the patient's PSIS and exerts pressure, then slides his thumb outward and then inward. The sign is positive if tenderness is increased. When sliding outward, trigger deposits in structures on the gluteal aspect of the PSIS may be noted. If tenderness is increased when sliding the thumb inward, it is indicative of sprain of the superior sacroiliac ligaments. Confirmation is positive when tenderness is increased when the examiner pulls the ASIS posterior while standing behind the patient or when the examiner pulls the PSIS forward while standing in front of the supine patient. These tests are helpful in determining that tenderness is due to overstressed superior sacroiliac ligaments.

Yeoman's Test.   The patient is placed prone. With one hand, firm pressure is applied by the examiner over the suspected sacroiliac joint, fixing the patient's anterior pelvis to the table. With the other hand, the patient's leg is flexed on the affected side to the limit, and the thigh is hyperextended by the examiner lifting the knee off the examining table. If pain is increased in the sacroiliac area, it is significant of a ventral sacroiliac or hip lesion because of the stress on the anterior sacroiliac ligaments. Normally, no pain should be felt on this maneuver.

Sacroiliac Ligament and Muscle Fixations

Illi has shown that sacroiliac fixation of any degree inhibits the compensatory torsion capacity of the spinal segments. When the mobile spine is flexed forward, there is always a degree of related lumbar torsion. However, if the sacroiliac joint is locked, normal torsion is inhibited and axial torsion of the cord and nerve roots occurs.


Around the sacroiliac articulations are a host of muscles and ligaments which, if normal in tension and elasticity, control movements and assure that they remain within normal limits. Unfortunately, most people use a majority of specific and specialized movements instead of maintaining a healthy general mobility. This causes one or several of these ligaments to shorten and tighten, which in turn causes the involved ligament to serve as a new, but abnormal, center of rotation that may restrict mobility in one or several directions. For instance, the pubic articulation may tighten and effectively stop A-P rotation of the ilia. In the sitting position, however, the sacrum will still be able to move between the ilia; in fact, hypermobility of both sacroiliac joints in the sitting position will occur, and at the same time, a total fixation of the ilia will be found in the standing knee lift test.

The greater the degree of sacroiliac fixation, the greater degree of stress placed upon the lumbosacral and hip joints. Any degree of sacroiliac fixation or hypermobility disturbing reciprocal motion bilaterally can be associated with:

(1) an adaptive lumbar scoliosis away from the side of pain, leading to biomechanical changes in the thoracic and cervical regions;
(2) the direction of excessive rotary forces to the lumbar spine, leading to disc failure;
(3) compensatory overstress at the acetabulum, leading to hip pain and arthritis;
(4) rotational overstress at the knee to widen the base of support, leading to chronic sprain.


No other area of the axial skeleton is prone to fixation from ligamentous shortening more than the sacroiliac articulations. In fact, Gillet feels that it is almost impossible to find a state of clinical imbalance that does not reflect this state. This is probably because few occupations require pelvic motion throughout the maximum range of possible motion. However, generalized bilateral ligamentous shortening in itself is not necessarily a cause of clinical concern even if a state of mobility is considered ideal. The clinical state of the sacroiliac ligaments is determined by the habitual positions the articulations are required to maintain.

The iliolumbar, sacroiliac, and sacrotuberous ligaments are common sites of ligamentous shortening that affect pelvic dynamics, and they appear to become involved in that order according to Grieve. Gillet, however, reports many cases of iliolumbar and sacrotuberous fixation without involvement of the sacroiliac ligaments.

The Iliolumbar Ligaments.   When an iliolumbar ligament becomes shortened, the iliac crest tends to be pulled medially while the ischium is forced outward. In response to the load above, the sacral base is forced anteriorly and the apex is forced posteriorly. Thus, the patient exhibits the normal state of the sitting pelvis while in the standing posture. This same condition may be the result of a fibrotic or reflexly contracted quadratus lumborum.

The Sacroiliac Ligaments.   When the posterior ligaments shorten, they tend to push the sacrum anteriorly so that the PSISs appear more prominent and closer together. When the anterior ligaments shorten, the sacrum has a tendency to bulge posteriorly, with an unusual mass palpable medial to the PSISs that have spread further apart.

The Sacrotuberous Ligaments.   These ligaments have a tendency toward considerable shortening. When shortened, the sacrum is seen displaced deeper between the two ilia like a driven wedge. With the patient in the lateral recumbent position, deep gluteal palpation will reveal taut cords. Grieve reports that ipsilateral calf and heel numbness is often associated, thus suggesting sciatic nerve involvement.


The Hamstrings.   Tight hamstrings are common, either bilaterally or unilaterally. As taut hamstrings will prevent pelvic flexion by fixing the ischium and destroying normal lumbosacropelvic rhythm, any motion achieved is forced upon the lumbar segments, often with compensatory stretching of the posterior longitudinal ligaments. If movement is forced, avulsion may occur leading to further degenerative changes.

The Lumbar Extensors.   Shortening of the lumbar extensors has the opposite effect as that of hamstring shortening. This is a cause and/or an effect of hyperlordosis. If the hamstrings are normal and the paravertebral muscles are tight, pelvic motion is free but lumbar flexion is restricted. If motion is forced, abnormal stress is placed upon the hips, sacroiliac joints, and posterior soft tissues of the lumbar region, leading to chronic strain, sprain, avulsion, spurring, and arthritis.


Theoretically, during static palpation, if the thumbs are placed on the PSISs and one thumb is more posterior and inferior or anterior and superior than the other when the patient is either standing or sitting, this would suggest a fixed unilateral pelvic rotation. Likewise, if the thumbs are placed on the PSISs and one thumb is more superior and anterior or inferior and posterior than the other when the patient is prone, this would suggest unilateral pelvic rotation. However, because osseous asymmetry is so common, these signs are frequently misleading. Dynamic tests correlated with other signs and the patient's symptoms are much more reliable during analysis.

Anterior Sacral Fixation.   In some patients, the anterior sacroiliac ligaments will have shortened, but not the posterior ligaments. These anterior ligaments can be divided into superior and inferior ligaments. If one of these is short, A-P rotation in the knee lifting test will still take place, but the center of rotation will have changed. Instead of taking place at the femur head, it will be found at the offending ligament and a related hypermobility will exist at the pubic articulation. This A-P mobility can be palpated by putting one thumb on the PSIS and the other thumb on the corresponding part of the sacrum. When the patient lifts his knee, the ilium on the same side will move posteriorly and down. If the contacts are taken on the inferior part of the ilium and sacrum, the former will be felt to move anteriorly. Furthermore, both of these movements will be sluggish, quickly reaching their limits and pulling the sacrum into a visible distortion.

Posterior Sacral Fixation.   Fixation at the posterior ligaments is more difficult to palpate and demonstrate as the palpating thumbs are on the actual center of rotation, thus registering no perceptible movement. However, if the patient is turned around and the ASISs are palpated, the knee lifting test will produce an abnormally wide mobility. It appears that these forms of sacroiliac fixations also insult the movement of the sacrum itself between the ilia, as tested in the seated patient, making it sluggish or even nonexistent. Bilateral shortening of these ligaments also markedly changes the in- and out-flaring of the normal pelvis when either standing and sitting.


As many pelvic distortions are reciprocal in nature, it is often confusing as to which side is the major. There are two general rules emphasized by Stierwalt that are helpful in many cases of pelvic misalignment:

(1) The primary subluxation-fixation concern is on the side of most pain, regardless if it is on the side of sacral anteroinferiority or posterosuperiority.
(2) The side of major misalignment is on the side to which the L5 has rotated, regardless of what direction the ilia have rotated. These rules should always be challenged and confirmed by other tests, however, for there are few clinical rules that are true in every case.


To screen general sacroiliac motion (ie, iliac flexion and extension on the sacrum) in the standing position, the examiner's thumbs are placed on the PSISs and the patient is asked to raise the right leg up and down, for example, bending the knee as if in taking a high step. The right PSIS will be felt to move osterior and inferior. After about 20 of leg raise, the left sacroiliac spine also drops posterior and inferior. This is normal sacroiliac motion. Any motion other than this indicates a problem in this joint. If the joint is fixated, the pelvis tends to move as a whole and the ipsilateral thumb will tend to remain level or even raise, rather than drop. These signs of thumb movement can be seen as well as felt.

Standing Test for Inferior Joint Motion.   A thumb is placed on the sacral apex and the other thumb on the ischial protuberance. The patient is asked to raise the knee on the side being tested. A 1/41/2-inch excursion should be felt as the ischium moves anterosuperior and lateral on the sacrum. If the inferior sacroiliac joint is locked, the ischium and sacral apex will move as a unit. Fixation of this motion is most often associated with a contralateral sacral base fixation. The direct mechanism is failure of the muscles acting on the sacral apex to elongate. Piriformis contracture is the common cause, but the iliopsoas or deep glutei may be involved.

Standing Test for Superior Joint Motion.   One thumb is placed on the sacral base and the other on the right PSIS, for example. The patient is asked to raise the right knee as if taking a high step, and the separation of the thumbs is noted. The sacral base will normally be seen and felt to move 1/41/2 inch anterior and inferior at the end of flexion. Or, conversely, the PSIS will move posterior and inferior. The sacroiliac tissues should be felt to relax. If the superior sacroiliac joint or the symphysis pubis is locked, the sacrum and ilium will move as a unit, the thumbs will not separate appreciably, and the sacral tissues (ligaments and spinal muscle attachments) will remain taut. This is probably the most common pelvic fixation found. Invariably, there is a degree of forward tilting of the pelvis associated with hyperlordosis.

Sitting Test for A-P Sacral Apex Motion.   To test forward flexion freedom with the patient sitting, a thumb is placed on one PSIS and the other thumb on the sacral apex. The PSISs are normally about 1/4 inch closer together in the sitting position than the standing position due to ischial spread. The separation of the thumbs should be noted as the patient flexes forward enough to flatten the lumbar curve. This will normally be about a half inch if the dynamics are normal, and the sacral tissues will be felt to tighten. If either the spinal extensors (multifidi, sacrospinalis) or pelvic extensors (hamstrings, gluteus maximus) fail to elongate during flexion, the sacroiliac joint will be inhibited from above or below, and the lumbars will remain somewhat lordotic. Thus, this type of fixation can be secondary to failure of the lower thoracic and lumbar muscles to elongate. Gluteal length can be further evaluated by flexing the thigh of the supine patient diagonally towards the opposite shoulder. To test A-P mion during extension, the same contacts are taken and the patient is asked to arch the back posteriorly. The distance between the thumbs should shorten, and the sacral tissues should relax.

Sitting Test for Iliac Horizontal Rotation.   With the patient sitting, the examiner's thumbs are placed on the PSISs and the patient is asked to fan his knees open and close several times. Normally, as the knees are abducted laterally, the PSISs move medially so that they are closer together. Quite frequently, one PSIS will be felt to move less than the other, pinpointing a fixation at the inhibited joint.

Sitting Test for Lateral Flexion of the Pelvis.   Both thumbs are placed on the PSISs so that the fingers firmly grip the crests of the ilia bilaterally. As the patient curves his trunk laterally, the lumbar spine should curve smoothly, the sacrum will normally tilt towards the side of the concavity, but the PSISs should remain relatively level even though there is some bilaterally reciprocal iliac rotation. The sacroiliac tissues on the side of lateral flexion should relax while those on the side of the convexity should tighten. At the end of voluntary motion, added thumb pressure on the sacrum in the direction of its movement should elicit further tissue relaxation. This will not occur if the ligaments have stiffened. If one PSIS raises during lateral flexion, it suggests elongation failure of the lumbar extensors (multifidi, erector spinae) or lateral stabilizers (iliopsoas, quadratus lumborum). If there is bilateral sacroiliac fixation, there will usually be associated lumbar fixation.

Test for Position Change Iliac Alterations.   The examiner's thumbs are placed on the PSISs of a patient seated on a stool. The distance between the contacts are noted. Then the patient is asked to stand and the distance between the thumbs are noted. Upon standing, the PSISs normally open laterally like a book so that the inter-PSIS distance increases. If a firm contact can be held on the ischial spines, a reverse reaction is seen; ie, the ischii tend to close medially when arising to the standing position. If fixation is present, these iliac and ischial motions will not be felt.

Test for Sacroiliac End-Play Motion.   The degree of translatory motion (end play) at the end of voluntary motion should be evaluated for ligamentous elasticity. The test is made at the end of extension by firm thumb pressure on the sacral apex while the other thumb is on the PSIS. This pressure should elicit further tissue relaxation.

     Trauma: Lumbar and Sacral Syndromes

The lumbar spine, sacrum, ilia, pubic bones, and hips work as a functional unit. Any disorder of one part immediately affects the function of the other parts. A wide assortment of muscle, tendon, ligament, bone, nerve, and vascular injuries in this area are witnessed in general practice.


The first step in the examination process is knowing the mechanism of injury if possible. With this knowledge, evaluation can be rapid and accurate. A complete history is vital to offer the most accurate diagnosis and the best management and counsel.

The mechanism of low back injury is usually intrinsic rather than extrinsic. The cause can often be through overbending, a steady lift, or a sudden release --all of which primarily involve the musculature. Intervertebral disc conditions are more often, but not exclusively, attributed to extrinsic blows and wrenches.

The Lumbosacral Triangle.     When viewed from the posterior, a clinical triangle can be drawn between the high points of the iliac crest and the sacral apex. This area includes the vast majority of structures that are most commonly involved in low back pain syndrome. Here we find the L4L5, lumbosacral, sacroiliac, and sacrococcygeal joints; the psoas, quadratus lumborum, iliocostal, longissimus, multifidi, interspinal and intertransverse muscles; the iliolumbar and transverse ligaments; and the extensive lumbosacral fascia.

Roentgenographic Considerations.     As in other areas of the body, x-ray views of the spine must be chosen according to the part being examined and the injury situation. And as with the cervical spine, careful evaluation must be made of the vertebral structures, the IVDs, and the paraspinal soft tissues. The L5S1 and sacroiliac joints, the pelvis, and its contents deserve careful scrutiny. Acute injuries to the supporting soft tissues about a vertebra are not clearly demonstrable, but their presence is suggested when the normal relations of bony structures are disturbed. When ligamentous lesions heal, hypertrophic spurs and sometimes bridges may develop locally on the margins of the bones affected.



The lower back and pelvis are the most common sites for avulsion-type injuries. Severe, sudden muscle contraction, especially during rotation in flexion, can produce fragmented osseous tears near sites of soft-tissue origin and insertion. Avulsions in the lumbar area often occur with transverse-process fragmentation at the site of psoas insertion. Helfet/Gruebel Lee feel this is the most common avulsion fracture of the body.


Howe points out that after falls or trauma to the back, particularly where the blow is applied to the bottom of the pelvis with the force traveling up the spinal column, compression fractures of vertebral bodies frequently result. The most often missed of these occur at the T12L1 junction, but they may possibly extend as high at T10 or T11. The reason they are often missed is that the pain is usually referred to the lumbosacral area, and there may be no spasm or even tenderness in the fracture area. If the x-ray beam is centered at the location of pain, the coned view may not extend high enough to include the lower thoracic area. A compression fracture is frequently not evident until several days later when deformity becomes more pronounced.


Isolated sacral fractures are almost always related to a direct blow from the posterior or the inferior. The mechanism of injury is sometimes associated with shear forces, when a blow to the sitting erect knee (eg, dashboard injury) drives the femur posterior, superior, and medial; rotation forces, where the hip is severely hyperextended; and/or leverage forces, where the A-P dimension of the pelvis is flattened. The fracture line is usually through the sacral foramina, which weaken the bone at these points.

NOTE:   You may also want to refer to:
Sacral Stress Fractures: Tracking Down Nonspecific Pain in Distance Runners
The Physician and SportsMedicine 2003 (Feb);   31 (2)


Although the transverse processes of the lumbar spine are quite sturdy, ultiple fractures are seen after severe accidents. Such fractures are sometimes not evident or are poorly visualized in roentgenography unless markedly displaced or angled due to overlying gas and/or soft-tissue shadows that obscure detail. Transverse process fractures are frequently asymptomatic or nearly so and often lack the symptoms to encourage the careful examination necessary.

Spinal Cord Injuries

Injuries to the lumbar cord or its tail occur from vertebral fractures, dislocations, or penetrating wounds in severe accidents. In rare instances, the cord may be damaged from violent falls with trunk flexion. The T12L1 and L5S1 areas are the common sites of injury, especially those of crushing fractures with cord compression. Neurologic symptoms develop rapidly, but the lower the injury, the fewer roots will be involved. More common than these rare occurrences are cord tractions, concussions, and less frequent contusions. Even a trace of sensory abnormality, objective or subjective, should immediately raise the suspicion of injury to the spinal cord or cauda equina.

White/Panjabi describe studies showing that during severe spinal trauma relaxed muscles appear to be associated with less cord injury than when the muscles are strongly tensed.


Concussion of the Spinal Cord.     Immediate signs are usually not manifested in mild or moderate injuries; but weeks later, lower extremity weakness and stiffness may be experienced. It takes time for nerve fibers to degenerate. Deep reflexes become exaggerated and originally mild sensory, bladder, and rectal disturbances progress. The picture is cloudy, often mimicking a number of cord diseases (eg, sclerosis, atrophy, syringomyelia). Life is rarely threatened, but full recovery is doubtful.

Contusions of the Spinal Cord.   Cord concussion usually complicates cord contusion. If laceration occurs, shock is rapid. Deep reflexes, sensation, and sphincter control are lost. The paralysis is flaccid. Obviously, a prognosis cannot be made until the shock is survived.

Pathologic Traction of the Spinal Cord.     A scoliotic lumbar deviation must always be attended by a commensurate vertebral body rotation to the convex side. If this does not occur, it is atypical and most likely pain producing. If the vertebral bodies were not subject to the law of rotation during bending, the spine would have to lengthen during bending and its contents (ie, cord, cauda equina, and their coverings) would be subjected to considerable stretch. Thus, in a case of scoliotic deviation in the lumbar area without body rotation towards the convex side, signs indicating undue tension within the vertebral canal should be sought. It should also be noted that atlanto-occipital, atlantoaxial, and coccygeal disrelation with partial fixation places a degree of traction upon the cord, dura, and dural sleeves in flexion-extension and lateral bending efforts.


Kernig's Leg Test.     The examiner flexes the thigh at a right angle with the torso and holds it there with one hand. With the other hand, the ankle is grasped and an attempt is made to extend the leg at the knee. If pain or resistance is encountered as the leg extends, the sign is positive provided there is no hip or knee stiffness or sacroiliac disorder.

Kernig's Neck Test.     Biomechanically, this test is the cephalad representation of Lasegue's straight-leg-raising test. The supine patient is asked to place both hands behind his head and forcibly flex his head toward his chest. Pain in either the neck, lower back, or down the lower extremities indicates meningeal irritation, nerve root involvement, or irritation of the dural coverings of the nerve root. That is, something is being aggravated by the tensile forces. When the examiner passively flexes the patient's neck and trunk, it is called the Soto-Hall test.

Milgram's Test.     The supine patient is asked to keep his knees straight and lift both legs off the examining table about 2 inches and to hold this position for as long as possible. This act stretches the anterior abdominal and iliopsoas muscles and increases intrathecal pressure. Intrathecal pressure can be ruled out in the typical adult if the patient can hold this position for 20 seconds without pain. If this position cannot be held or if pain is experienced early during the test, a positive sign is offered that indicates, for example, intrathecal pathology, herniated disc, or pressure upon the cord from some source.


In the well-conditioned individual, IVD conditions are more often, but not exclusively, attributed to extrinsic blows or wrenches. An accurate and complete history is vital to arrive at an accurate diagnosis and offer the best management and counsel.

Horizontal shear forces appear to be the most damaging forces for disrupting the ligamentous strapping between vertebrae. Because of the lax capsules, a minor sprain can produce a severe synovitis at the posterior joints. If the synovium is torn on the side of tension, irritating hemarthrosis results and fragments of fractured articular cartilage and periosteum may form loose bodies in the joint. The distorted articular surface may produce chronic instability from erosion and degeneration, leading to reactionary osteophytoses which, in turn, are subject to fracture. Repeated episodes of minor trauma and tissue changes predispose progressive degenerative arthritis.

Also see Acute Lumbosacral Angle Syndromes and Table 12.13 in this chapter.


Acute lumbosacral sprains have a high incidence. They occur most often in the 2550 age group, and sedentary workers are involved just as frequently as workers doing heavy labor. Heavy loads or severe blows, especially at an unguarded moment, may rupture some associated ligaments and/or subluxate the joint. Pain may be local or referred. Overt symptoms are usually relieved by rest and aggravated by activity and high heels, but fatigue is chronic regardless of adequate rest. Care must be taken to differentiate these sprains from a sacroiliac, hip, rectal, or pelvic lesion. Localized tenderness and the standard clinical tests are helpful in differentiation.


Sacroiliac sprains with overt rupturing are of infrequent occurrence. Overloading and severe blows are the typical allopathic explanations, but these causes are considered infrequent by chiropractors and osteopaths unless severe ligament rupture and acute subluxation are associated. Careful differentiation is important because the intrinsic strength of the posterior ligaments makes severe sprain unlikely and because the joint is the common site of diffuse referred pain and tenderness.

Because the sacroiliac joint is so often the site of referred pain and tenderness (eg, lumbar disc, upper cervical fixation), it is unrealistic to automatically attribute these signs to the joint itself. However, we should also avoid the tendency to generalize that all such symptoms and signs are referred.

Etiologic Picture.     Straightening up or lifting from a stooped position can cause a traumatic unilateral or bilateral displacement of the sacrum within the ilia, thus spraining the sacroiliac and iliolumbar ligaments. In this position, body weight (plus loading) pulls the sacrum anterior, while taut pelvic extensors pull the ilia posterior. Most sacroiliac sprains, however, are not the result of severe overloading or drastic trauma. They are more frequently the result of a misstep, an awkward twist during flexion, or torsional overexertion (eg, shoveling). These common occurrences could hardly be classified as traumatic enough to tear the strongest ligaments of the body. The question arises: What makes this normally strong and slightly movable joint displace? The explanation is the same as that previously given for the cause of many vertebral subluxations.

Inhibited motion at some point within the normal range of sacroiliac movement is compensated by hypermobility at adjacent segments such as the lumbosacral, pubic, and proximal femur articulations. Likewise, a degree of lumboacral or hip fixation leads to adaptive sacroiliac and pubic loosening and instability that predisposes sprain by normal activity forces. It is for this reason that the direct cause of a sacroiliac sprain-subluxation may not be within the joint itself and recurrence can only be avoided if the coupled joints, ligaments, and muscles are kept elastic. Once the coupled restrictions are normalized, the unstable joints will slowly tighten to meet their natural requirements.

Pregnancy is another cause of adaptive loosening of the sacroiliac and pubic joints, but the cause is hormonal rather than adjacent fixation. Grieve's studies showed that the normal symphysis pubis width of 4 mm increases to 9 mm, and some separations have been recorded up to 2 cm. Obvious changes can be recognized as early as the fourth month of pregnancy, and normal joint tightness does not usually return until 612 weeks after delivery.

Pertinent Associated Complaints and Findings.     During visual analysis, the patient assumes the characteristic standing posture with a flattened lumbar area and weight placed on the unaffected side. The trunk is inclined away from the painful lesion. There is a guarded gait and limited spinal motion, especially spinal flexion due to hamstring tension. Trunk rotation is rarely inhibited as this takes place primarily in the thoracic spine. Because of gluteal inhibition, a definite Trendelenburg lurch may be exhibited during gait. In most cases, restricted mobility will be found in thigh flexion or hyperextension.

Jarring the spine causes a sharp localized pain in the affected joint. The pain usually radiates over the ipsilateral hip and down the anterior thigh. These symptoms are usually relieved by rest and aggravated by activity. When the gluteus medius shortens to abduct the hip when the patient is laterally recumbent, the contraction tends to separate the ilium from sacrum. If the sacroiliac joint is inflamed from trauma or disease, abduction of the thigh against resistance is acutely painful.

Stress upon the joint should increase pain such as in lateral compression or torsion of the iliac crests. Tenderness will be found inferomedial to the PSIS and often at the pubic symphysis, contralateral anterior acetabulum, and fascia lata. Care must be taken not to confuse sacral base tenderness from local ligamentous stress with that of tender sacrospinalis muscle fiber insertions. Lasegue's tests are unpredictable. If the sprain is "hot," Lasegue's supine test will definitely be positive between 30 and 60.

Differential Diagnosis Tips.     Care must be taken to differentiate the symptoms of sacroiliac sprain from a sacral base lesion, lumbar subluxation, or pelvic pathology. Special roentgenographic and laboratory analyses are necessary if symptoms do not respond as anticipated. Localized point tenderness and the standard kinesiologic and orthopedic tests are helpful in differentiating mimicking musculoskeletal disorders.


Low back disability has an extremely high incidence, and acute strains are frequently superimposed on chronic strains. Because of the increased lever arm operating on the lumbar segments, the incidence of injury is two times higher in taller individuals than shorter people.


Any movement or distortion of the lumbar spine affects the pelvis, and any movement or distortion of the pelvis affects the lumbar spine. Thus, postural distortions of the lumbar area with a muscular etiology should never be considered apart from the pelvis. However, a case will occasionally be seen that exhibits a major lumbar distortion with normal pelvic function.


The mechanism of injury is usually intrinsic rather than extrinsic. The precipitating cause is often through overbending, a steady lift, or a sudden release --all of which primarily involve the musculature. The most damaging forces are compression with torsion. When a weight is lifted, the arms and trunk can be considered a long anterior lever that is counteracted by the extremely short lever extending from the disc nucleus (fulcrum) to the spinous process. This has been estimated as a 15:1 ratio; thus, holding a 20-lb weight in front with the arms held horizontal must be counteracted by at least a 300-lb contraction of the spinal extensors to maintain equilibrium.

Chronic strain results in fine fibrous intramuscular adhesions that interfere with normal motion. The features are a history of trauma, palpable swelling within the involved muscles, and trigger-point tenderness. Helfet/Gruebel Lee feel this occurs most frequently at the junction of tissues of differing elasticity (eg, attachments). Overstress disrupts muscle fibers, and this produces bleeding, swelling, and exudate organization leading to further adhesions. These adhesions respond well to manipulative therapy, but they will recur unless the joint is exercised a few minutes a day to its maximum range of motion.

In general, the process can be described in two phases:

(1) Stress is applied to weakened muscles, which produces stretching and inflammation. Initially, the stretched soft tissues will be lax and the joint will exhibit a degree of instability once spasm subsides.
(2) Later, protective and fibrotic soft-tissue shortening develops as soft tissue readily adapts to activity needs. If articular subluxation is also involved, the result is shortening on one side of the joint and stretching on the other side that tend to hold the joint in chronic subluxation. In time, articular "gluing" and periarticular bony overgrowth will develop to fix the joint in the misaligned state.


The associated pain may be immediate or not occur for several hours after the tissues warmed by physical activity begin to cool.

In almost every case of acute lumbosacral stress, the local multifidi will be stiff or possibly mildly splinted. When this happens, Cailliet states that the motion unit will be kyphotic. This cannot be true because the multifidi are hyperextenders in the erect position that can only produce locking in lordosis. Shortened abdominals and possibly the psoas major would be the logical muscles in the lumbar area responsible for kyphotic fixation. Anterior disc collapse or a fixed facet separation would be a more logical cause if a segmental kyphosis is present. An associated lumbar scoliosis with pain on the side of the concavity is evidence of psoas major involvement.