<prompt> In the lumbar spine, 90 of the disc herniations occur at which of the following level:L1-L2L2-L3L3-L4L4-L5  <response>: Ans. d L4-L5Ref: Maheshwari 5th ed. 253 Most common site of spinal disc herniation: Lumbar region 95 in L4-L5 or L5-S1. The second most common site is the cervical region C5-C6, C6-C7. Thoracic region accounts for only 0.15 to 4.0 of cases. Herniations usually occur posterolaterally, where the annulus fibrosis is relatively thin and is not reinforced by the posterior or anterior longitudinal ligament. In the cervical spinal cord, a symptomatic posterolateral herniation between two vertebrae will impinge on the nerve which exits the spinal canal between those two vertebrae on that side. For example, a right posterolateral herniation of the disc between vertebrae C5 and C6 will impinge on the right C6 spinal nerve. 