WILLET V ROWEKAMP Supreme Court of Ohio 08-03-38
Background: An unlicensed doctor of chiropractic was sued for malpractice following a high velocity rotational maneuver to the lumbar region causing injury to plaintiff. X-rays were not taken. Two actions were brought, one for malpractice and negligence, the other for practicing chiropractic without a license which had no bearing on the negligence (med-mal) issue and was dealt with later in the criminal courts.
Physicians and Surgeons 15. A patient to maintain an action against chiropractor for injuries resulting from alleged malpractice must show that the injury complained of was due to negligence or unskilled treatment. (emphasis added)
The supreme court finally got the case. Here is their decision. Even though this is an old case, it is on the books and I feel it is relevant to your question:
"Hence, there is some evidence that the failure to use x-ray resulted in an erroneous diagnosis, and evidence in the record indicates that the use of x-ray is required, it being difficult to diagnose such subluxation or dislocation without the employment of x-ray. It is complained too, that the plaintiff was unduly restricted in her evidence respecting the subject of diagnosis."
further... "Diagnosis must be regarded as important as is the treatment to be administered, for faulty diagnosis may result in treatment which is not only not correctional and curative, but is positively harmful in character.."
Although this case is some sixty years old, it reads like it came out of the courts today, and I feel merits serious consideration by both detractors and supporters of the vertebral subluxation complex ideology.