Health Encyclopedia

Femoral nerve dysfunction

Definition

Femoral nerve dysfunction is a loss of movement or sensation in the leg due to nerve damage.

Alternative Names

Neuropathy - femoral nerve

Causes, incidence, and risk factors

The femoral nerve is located in the leg and supplies the muscles that help straighten the leg. It provides sensation to the front of the thigh and part of the lower leg.

Damage to a single nerve group such as the femoral nerve is called mononeuropathy. Mononeuropathy usually means there is a local cause of the nerve damage, although disorders that involve the entire body (systemic disorders) can also cause isolated nerve damage (such as occurs with mononeuritis multiplex).

The usual causes of femoral nerve dysfunction are direct trauma, prolonged pressure on the nerve, and compression of the nerve by nearby body structures or disease-related structures (such as a tumor). Prolonged pressure may be complicated by lack of oxygen caused by decreased blood flow (ischemia) in the area.

Entrapment involves pressure on the nerve where it passes through a narrow structure (for example, as it passes through a muscle). The damage includes destruction of the myelin sheath of the nerve or destruction of part of the nerve cell (the axon). This damage slows or prevents nerve impulses from passing through the nerve.

The femoral nerve can be injured due to pelvic fractures. It can be injured when a catheter is placed in the artery in the groin (femoral artery). It can be affected by diseases causing damage to many nerves (polyneuropathy), such as diabetes. It also can be damaged by pressure from tumors, abscesses, or internal bleeding into the pelvis or abdomen.

One common risk factor is lying on the back with the thighs and legs flexed ("lithotomy" position) during surgery or diagnostic procedures. In some cases, no cause can be found.

Symptoms

Sensation changes in the thigh, knee, or leg, such as decreased sensation, numbness, tingling, burning, a feeling of the knee "giving way" or buckling, or (uncommonly) pain
Weakness of the knee or leg, including difficulty going up and down stairs -- especially down

Signs and tests

An exam of the nerves and muscles (neuromuscular exam) of the legs shows femoral nerve dysfunction. You might have weakness when you straighten the knee or bend at the hip. Sensation changes are located on the front of the thigh and inner calf. The knee jerk reflex may be decreased or absent. You may have a loss of muscle mass (atrophy) in the quadriceps muscles of the front of the thigh.

Tests that reveal femoral nerve dysfunction may include:

EMG
MRI to check for masses or abnormal tissue (lesions)
Nerve conduction tests

You'll have tests based on the suspected cause of the dysfunction, which is suggested by your history, symptoms, and pattern of symptom development. These tests may include various blood tests, x-rays, scans, or other tests.

Treatment

Treatment is aimed at increasing mobility and independence. Your health care provider should identify and treat the cause of the damage if necessary. In some cases, no treatment is required and you'll recover on your own.

Conservative treatment is given if there is sudden onset of symptoms, minimal sensation or movement changes, no history of trauma to the area, and no sign of nerve degeneration.

Corticosteroids injected into the area may reduce swelling and pressure on the nerve in some cases. You may need pain medication to control your symptoms. Various other medications can reduce the stabbing pains that some people experience. Whenever possible, avoid or limit medication to lessen the risk of side effects.

Some people might benefit from surgical removal of tumors or other growths that press on the nerve.

Physical therapy may be helpful to maintain muscle strength. Orthopedic appliances such as braces or splints may help in walking. Your health care provider might recommend vocational counseling, occupational therapy, job changes or retraining, or similar interventions.

Expectations (prognosis)

If the cause of the femoral nerve dysfunction can be identified and successfully treated, it is possible to recover fully. In some cases, there may be partial or complete loss of movement or sensation resulting in some degree of permanent disability.

Nerve pain may be quite uncomfortable and can continue for a long time. Trauma to the femoral area may also injure the femoral artery, which can cause fatal bleeding.

Complications

A complication is a recurrent or an unnoticed injury to the leg.

Calling your health care provider

Call your health care provider if you develop symptoms of femoral nerve dysfunction.

Prevention

Prevention depends on the cause of the nerve damage.

Review Date:11/1/2007
Reviewed By:Luc Jasmin, M.D., Ph.D., Departments of Anatomy and Neurological Surgery, University of California, San Francisco, CA. Review provided by VeriMed Healthcare Network.

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