When an intervertebral disc extrudes through the capsule, it won’t go back and often surgery is the only way to relieve the pain. Some extruded fragments go into the “armpit” (the axilla) of a nerve root. In those cases straight leg raising of the “well leg” (A), as illustrated, increases pain in the painful leg by pulling across the dural sac to put more pressure on the painful opposite nerve (C) This is the crossed straight leg-raising test (XSLR). It is diagnostic of an extruded herniated disc.
