The symptoms of L4 and L5 nerve damage are leg pain that shoots down the leg to the foot, says Spine-health. The pain is often accompanied by numbness. This is a symptom of a herniated disc in the lumbar spine.
When the disc between the L4 and L5 vertebrae ruptures, it squeezes against the nerves that run through the vertebrae and irritates them, says Spine-health. Because the nerves that come from the L5 vertebrae control the feet and the big toes, the muscles there are weakened if the nerves are impinged. The top of the patient's foot also feels numb. However, because the spinal cord stops at the end of the thoracic spine, even a seriously herniated disc in the lumbar spine does not usually cause paralysis in the legs.
However, a more serious condition called cauda equina syndrome can occur when the bundle of nerves that branch off from the spinal cord and are found in the lumbar spine are severely compressed, says the American Association of Orthopaedic Surgeons. This is a rare condition whose symptoms include paralysis that can become permanent, incontinence and other problems with the lower extremities. Cauda equina syndrome, which can be caused by a herniated disc, tumors or fractures of the lower spine, is considered a medical emergency.