Femoral nerve is present in the leg. It supplies the leg muscles that enable the leg to straighten. It is also responsible for sensation in the anterior (front) region of the thigh and the lower leg. This nerve originates from the lumbar plexus in the spine, passes through the psoas muscle in the pelvis, follows further down to supply the quadriceps in the thigh and then continues as a sephenous nerve in the calf muscle.
Femoral nerve damage can be due to a direct trauma or as a consequence of a disease or an iatrogenic cause (caused while performing any surgical or medical procedure).The damage to the nerve can be partial or complete. Although femoral nerve damage is not so common, there are possibilities of it getting injured in various circumstances.
Causes Of Femoral Nerve Injury
The causes of femoral nerve damage are as follows:
- Direct trauma due to penetrating wounds such a gunshot injury or it can also occur due to fracture of the pelvis or the hip bone. A deep laceration in the thigh region can also affect the nerve supply to the quadriceps.
- Iatrogenic origin: while performing certain abdomino- pelvic operations, or catheterization during coronary angiography as the nerve lies just next to the femoral artery through which the catheter is introduced.
- Lithotomy position at the time of gynecological examination or during the time of delivery, the nerve is compressed, resulting into damage to some of its fibers.
- Compression due to aortic aneurysm or tumors.
- Compression in the psoas muscle due to hematoma caused because of anti coagulant therapy or in certain disease called hemophilia.
- Abscess in the psoas muscle.
- Diabetes: it causes damage to the femoral nerve cells, resulting into neuropathy.
- Compression due to tumors example; synovial cyst, sarcoma etc.
- Neonatal femoral nerve damage is caused as a result of breech presentation.
Femoral Nerve Damage Symptoms
- Weakness and instability of the knee while climbing stairs, which often result into ‘buckling of knee’.
- The weakness is acute and not as seen in myopathy where the onset is gradual with involvement of both the limbs.
- Numbness in the thigh and the calf region in the lower leg.
- Burning pain in the front portion of the thigh also known as meralgia paresthetica.
- Pain in the inguinal ligament.
- Absence of knee reflex.
- Quadriceps becomes short due to wasting and there is weakness of quadriceps, it is the most striking feature of femoral nerve damage.
- Pain in the groin, thigh on extending the hip.
- Tingling in the thigh, knee and leg.
Femoral nerve damage is diagnosed with the help of:
- Electromyography. (EMG)
- CT or MRI of the abdomen to exclude hematoma in the retroperitoneal region, tumor and aneurysm of the arota.
- Nerve conduction studies.
- X-ray, blood examination,
The above tests help to conclude the diagnosis in case of femoral nerve damage.
Treatment Of Femoral Nerve Injury
The first step is to identify the underlying cause for femoral nerve damage. Once diagnosed, if the condition is not severe, the person may require conservative mode of treatment. In some cases treatment is not required and the patient will recover on its own.
Supportive treatment is given when there is no major symptom observed that affect the movement or sensation. Exercise and physiotherapy are effective, besides medication.
Surgical treatment may be required in case of certain conditions such as:
- Drainage in case of psoa abscess or hematoma.
- Decompression of nerve.
- Penetrating wounds.
If the underlying cause is identified and treated completely, there is full recovery.
- In most cases there is spontaneous recovery.
- In some cases there may remain residual loss of movement or sensation permanently.
- In case of compression or overstretching as in obstetrics and gynecological surgery it may take three to six months to recover.