When suffering from a pinched nerve symptom in the leg, the trick is figuring out whether the nerve is in the leg itself or in the lower back. The leg has only a few major nerves and only a few places where those nerves could be pinched, so accurate diagnosis and thus proper treatment is relatively straightforward. Clinical examination is the most important tool in that regard, and if necessary a nerve test called an EMG can provide additional details.
In the Back
The first and most common location for a pinched nerve is in the back. Radiculopathy refers specifically to a nerve root being impinged right where it comes out of the spine. Typically this causes tingling and/or pain partially or all the way down the leg. If more severe, it may also lead to weakness of muscles controlled by that nerve. The treatment depends on what specifically is pinching the nerve—for example, a herniated disc, arthritis or scar tissue. Physical therapy can often relieve the problem, but sometimes epidural injections are needed for pain relief. Surgery may be needed to definitively solve the problem, particularly if the problem is progressive.
In the Buttock
Sciatica is the general term for pain that radiates down the back of the leg, and piriformis syndrome is one of the possible causes. It occurs when the piriformis muscle in the middle of the buttock spasms and compresses the large sciatic nerve that runs under it or sometimes through it. Physical therapy is the main treatment. It involves loosening the muscle and its grip on the nerve. Therapy should also correct the underlying issues that led to the spasm. Very rarely, surgical release of the muscle is necessary.
At the Knee
The peroneal nerve, a major branch of the sciatic nerve, wraps around the outside of the knee, just under the skin. Being so superficial, it is prone to being compressed—most commonly by the other knee when your legs are crossed—which typically results in temporary tingling or numbness of the lower leg or foot or even foot weakness. Usually symptoms are self-limited and no treatment is needed. However, if the nerve was pinched for a prolonged period or symptoms do not resolve quickly, there may be actual nerve damage. Again, physical therapy would be the main treatment to address nerve stimulation and strengthening as needed. If you're experiencing foot drop, an orthotic boot or plastic mold may be needed to support the foot.
At the Ankle
Tarsal tunnel syndrome is the compression of the nerve within the tarsal tunnel on the inside of the ankle. Bones and the overlying connective tissue form this tunnel through which nerves and some tendons travel on their way to the foot. It is very similar to the carpal tunnel syndrome at the wrist. Symptoms can include numbness, tingling, pain, and cramping on the bottom of the foot. Anti-inflammatory drugs can relieve any inflammation in the tunnel that may contribute to the compression, and physical therapy can further relieve the pressure in the tunnel as well as restore normal nerve function. Steroid injections can be of benefit in some cases. Occasionally surgery is required to open the tunnel and relieve the pressure on the nerve.
In the Foot
Morton neuroma is a knot of thickened tissue around an irritated nerve, usually on the undersurface of the foot, between the third and fourth toes. Commonly resulting from tight shoes, neuromas develop due to constant pressure or irritation on the forefoot and cause numbness, stinging pain or tingling in the toes. A change of shoes, use of shoe inserts or orthotics, steroid injections, and physical therapy are all potential treatments. Surgery is possible but not usually necessary.