Impingement of the nerve root at S1 causes symptoms such as weakness at the back of the calf, numbness on the outside of the foot, difficulty with foot push-off and absence of the ankle jerk reflex, states Spine-Health. Pain often radiates down the lower back, through the buttock, down the back of the thigh and calf, to the side of the foot, says the Laser Spine Institute. Nerve root impingement at L5-S1 results from a common type of disc herniation.
As the discs of the spine degenerate, disc herniation can result as the inner core of the disc leaks out through the outside of the disc, compressing the spinal nerves, according to Spine-Health. The nerve at L5-S1 runs down through the leg, which causes pain and weakness in the leg and foot to occur with impingement of this nerve.
In many cases, the pain resolves on its own after approximately six weeks. During this time, the patient may find relief from physical therapy, chiropractic manipulation, heat or ice therapy, pain medication or cortisone injections, explains Spine-Health. If severe pain and other symptoms continue beyond this period, the patient may need microdiscectomy surgery to obtain relief. This surgery involves the removal of the small portion of bone that is pressing against the nerve, allowing the nerve a better opportunity to heal.