Anatomy
Summary
The femoral nerve is the largest branch of the lumbar plexus, stemming from the posterior divisions of the anterior rami of L2-L4 and serving both sensory and motor functions. Notably, the femoral nerve gives off the medial femoral cutaneous and intermediate femoral cutaneous nerves, which provide sensation to the anteromedial thigh. Another significant branch is the saphenous nerve, a pure sensory nerve supplying the medial leg. Motor innervation includes hip flexors such as the iliopsoas, pectineus, and sartorius, as well as knee extensors such as the quadriceps femoris musclesÑrectus femoris, vastus lateralis, vastus intermedius, and vastus medialis.
Injury to the femoral nerve can occur due to various causes such as pelvic trauma, pelvic fractures, retroperitoneal hematoma, pelvic abscess, pelvic surgery, and childbirth. The consequences of a femoral nerve injury includes sensory loss to the anteromedial thigh (medial & intermediate cutaneous femoral nerves) and medial leg (saphenous nerve). Motor deficits include weakness in hip flexion and knee extension, often manifesting as difficulty in walking stairs, as well as loss of the patellar reflex.
Lesson Outline
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FAQs
The femoral nerve is one of the largest nerves in your body. It originates from the lumbar plexus and passes through the pelvis to become the primary nerve supplying the anterior compartment of the thigh. The primary functions of the femoral nerve are to innervate the hip flexors and knee extensors, allowing for movements such as walking, running, and climbing.
The branches of the femoral nerve primarily dedicated to sensory functions are the medial and intermediate femoral cutaneous nerves and the saphenous nerve. The medial and intermediate femoral cutaneous nerves emanate from the femoral nerve to supply sensation to the anteromedial region of the thigh. The saphenous nerve is a purely sensory branch of the femoral nerve and is responsible for providing sensation to the medial side of the leg.
The femoral nerve supplies the hip flexors, including the iliopsoas, pectineus, and sartorius muscles. It also innervates the quadriceps femoris muscles, which are vital for knee extension. These muscles include the rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius.
Femoral neuropathy is a condition that can result from damage to the femoral nerve. Symptoms can include weakness in the knee and hip, decreased patellar reflex, and difficulty extending the knee or lifting the hip. Additionally, sufferers may experience numbness or tingling in the leg due to sensory changes. It's important to seek medical advice if these symptoms are experienced, as they could also be related to other conditions, including issues involving the sciatic nerve.
The patellar reflex is a sudden extension of the knee in response to a sharp tap on the patellar ligament, and the femoral nerve plays a key role in this reflex action. When the patellar ligament is struck, it sends a signal via the femoral nerve to the spinal cord. The spinal cord then sends a signal back through the femoral nerve to the quadriceps muscle, causing it to contract and extend the knee.
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