Nerves facilitate communication between the brain and body, enabling movement and sensation. The femoral nerve is a major lower limb nerve, crucial for leg function by controlling muscles and transmitting sensory information.
Its Path Through the Body
The femoral nerve originates in the lower back from the lumbar plexus, a network of nerves formed by spinal roots L2, L3, and L4. It descends through the abdomen, passing between the psoas major and iliacus muscles. The nerve then enters the thigh by passing beneath the inguinal ligament, a strong band of tissue in the groin.
In the anterior thigh, the femoral nerve enters the femoral triangle, positioned laterally to the femoral artery. After passing the inguinal ligament, it divides into anterior and posterior branches. These branches extend throughout the thigh, supplying muscles and skin regions.
Role in Movement and Sensation
The femoral nerve performs motor and sensory functions in the lower limb. Its motor branches primarily innervate the quadriceps femoris muscles—rectus femoris, vastus medialis, vastus lateralis, and vastus intermedius—which extend the knee. The nerve also supplies hip flexors like the iliacus and pectineus, aiding in thigh lift.
The femoral nerve also provides sensation to specific leg areas. Its sensory branches, including the medial and intermediate femoral cutaneous nerves, supply sensation to the skin of the anterior and medial thigh. The saphenous nerve, the longest sensory branch, extends further down the leg, providing sensation to the medial knee, lower leg, and parts of the medial foot.
When the Femoral Nerve Causes Problems
Problems affecting the femoral nerve can impact mobility and sensation. If irritated, compressed, or injured, individuals may experience weakness extending the knee. Difficulty flexing the hip can also result from impaired hip flexor function. These motor deficits make activities like walking or climbing stairs challenging.
Sensory disturbances are common when the femoral nerve is affected. People may report numbness, tingling, or a burning sensation in the anterior thigh. These sensations can extend to the medial lower leg and foot, following the saphenous nerve’s distribution. Causes of femoral nerve problems include injury, prolonged pressure from positions or tight clothing, or inflammation. Conditions like pelvic fractures or internal bleeding in the abdomen can also cause nerve compression.