[Low back pain and instability of the pelvic ring]

Low back pain is a major cause of disability, and a large percentage of patients with low back pain have no identifiable pathology. In this review of the literature low back pain is considered from the point of view of dysfunction of the pelvic joints. The reliability of the commonly used tests, signs and procedures are considered. Inflammatory causes such as ankylosing spondylitis are well documented to cause low back pain, but mechanical factors apart from intervertebral disc protrusion are largely speculative.