A 62 year old man is seen in an emergency depament because of severe pain in his lower back, left buttock and the posterolateral aspect of his left leg. The pain began acutely after he lifted his 8 year old granddaughter into the back of a truck, and he describes it as "shooting" in nature. When examined by the physician, he has curled into a fetal position, which he says relieves the pain. Attempts to extend the man's spine cause a marked exacerbation of the pain. More detailed examination demonstrates foot drop with weakness of the anterior tibial, posterior tibial, and peroneal muscles. Sensory loss is demonstrated over the anterior shin and dorsal foot. These findings suggest a radiculopathy at which of the following cord levels?
High-Yield Explanation
The findings are typical for involvement at the L-5 level. Most ruptured disks involve either the lumbar area L55 and S-1 most common) or the cervical area (C-6 and C-7 most commonly). Compression by a disk of the cervical cord can produce a spastic paresis of the lower limbs; compression of the cauda equina can cause urine retention or incontinence.C-7 supplies the back of the shoulders, down the back of the arm, past the elbow, to the back of the second and third fingers. S-3 supplies a small area on the buttocks. T-9 supplies a band on the abdomen and back that passes above the umbilicus.