The femoral nerve is located in the leg. It helps the muscles move the hip and straighten the leg. It provides feeling (sensation) to the front of the thigh and part of the lower leg.
A nerve is made up of many fibers, called axons, surrounded by insulation, called the myelin sheath.
Damage to a nerve 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:
Direct injury (trauma)
Prolonged pressure on the nerve
Compression or entrapment of the nerve by nearby parts of the body or disease-related structures (such as a tumor)
Prolonged pressure on the nerve decreases blood flow in the area. This can lead to further complications.
The femoral nerve can be also be damaged if you have:
A broken pelvis bone
A catheter placed into the femoral artery in the groin
Diabetes, which can cause widespread nerve damage
Internal bleeding in the pelvis or belly area (abdomen)
One common risk factor is lying on the back with the thighs and legs flexed and turned ("lithotomy" position) during surgery or diagnostic procedures. Branches of the femoral nerve can be compressed by tight or heavy waist belts. In some cases, no cause can be found.
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
The doctor or nurse will examine you. This will include an exam of the nerves and muscles in your legs.
The exam may show:
You might have weakness when you straighten the knee or bend at the hip
Sensation changes are located on the front of the thigh
You may have an abnormal knee reflex
The quadriceps muscles on the front of the thigh may be smaller than normal
Your doctor may order additional tests, depending on your medical history and symptoms. Tests may include blood tests, x-rays, and other imaging tests.
Your doctor will try to identify and treat the cause of the nerve damage. In some cases, no treatment is required and you'll recover on your own. In that case, any treatment is aimed at increasing mobility and independence while you recover.
Supportive treatment is usually given if the symptoms come on suddenly, if there is only minor sensation or movement changes, no history of trauma to the area, and no sign that nerve function is getting worse.
Other treatments include:
Corticosteroids injected into the area to control obvious swelling or inflammation.
Pain medication, if necessary. Various other medications can reduce the stabbing pains that some people experience. The benefits of medications should be weighed against any possible 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.
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. Injury to the femoral area may also injure the femoral artery or vein, which can cause bleeding and other problems.
When there is a loss of feeling (sensation), a potential complication is repeated and unnoticed injury to the leg. When there is muscle weakness, falls and related injuries may occur.
Calling your health care provider
Call your health care provider if you develop symptoms of femoral nerve dysfunction.
Prevention depends on the cause of the nerve damage.
Misulis KE. Lower back and lower limb pain. In: Bradley WG, Daroff RB, Fenichel GM, Jakovic J, eds. Neurology in Clinical Practice. 5th ed. Philadelphia, Pa: Butterworth-Heinemann; 2008:chap 33.
Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine; David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.