The lateral bending sign

In lumbar disc herniations, musculoskeletal findings usually predominate at the outset. There is often an acute list or impaired lateral mobility to one side or the other. This finding represents a protective mechanism to splint the affected disc space in the position where the disc prolapse exerts the least possible pressure on the affected nerve root. An attempt was therefore made to determine whether the relationship of the disc herniation to the nerve root could be delineated by having the patient bend maximally to each side. Three hundred patients who would normally be candidates for routine (static) x-ray study of the lumbar spine had lateral bending (dynamic) films instead. These were then correlated with myelograms and/or surgery, when performed. Lateral bending roentgenograms can often pinpoint the level of lumbar disc herniation.