Introduction
The femoral nerve is the largest nerve in the lumbar plexus. It has a motor function that will assist in moving the hips, legs, ankles, and feet. It also serves as a sensory aid, allowing it to detect touch, pain, and hot or cold temperatures. The femoral nerve is a peripheral nervous system nerve. This system sends signals from the brain to the lower and upper limbs and some organs. It is formed by the dorsal divisions of the ventral rami L2-L4. It regulates the major hip flexor and knee extension muscles. It also regulates sensation in the anterior and medial thigh, as well as the medial leg down to the hallux (big toe). As a result, it has several branches as it travels from the lumbar spine to the pelvis and then to the lower limbs.
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The femoral nerve divides into the anterior (superficial) and posterior (deep) femoral nerves near the pubic bone. Each of these branches performs a specific motor or sensory function:
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Sensory functions are provided by the anterior femoral nerve, which runs through the front and middle of the thigh.
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The saphenous nerve, which supplies sensory information to the lower leg and foot, is formed by the posterior femoral nerve.
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The anterior femoral branch aids in hip flexion and movement.
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The posterior femoral branch directs the quadriceps muscles, aiding knee straightening.
What Is the Location of the Femoral Nerve?
The femoral nerve:
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Originates in the lumbar plexus from the L2 to L4 nerve roots.
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The femoral triangle is a hollow, wedge-shaped area between the upper thigh and the groin. The femoral nerve, artery, vein, and lymphatic vessels all pass through this triangle.
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It continues down the front of the thigh in between psoas major and hip flexor muscles.
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It follows the femoral artery, a large blood vessel that transports blood to the lower limbs.
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Under the inguinal ligament, it divides into two nerves, anterior and posterior.
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The saphenous nerve is formed by the posterior division at the adductor canal, a narrow tunnel-like opening in the thigh. The saphenous nerve innervates the knee, lower leg, ankle, and foot.
What Are the Functions of the Femoral Nerve?
Motor Functions:The anterior thigh muscles are supplied by the femoral nerve:
1. Hip Flexors:
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Pectineus adducts and flexes the thigh and aids in medial thigh rotation.
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Iliacus works with the psoas major and minor to flex the thigh at the hip joint and stabilize the hip joint (forming iliopsoas).
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Sartorius located at the hip joint, flexes, abducts, and laterally rotates the thigh.
2. Knee Extensors:
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Quadriceps femoris (vastus lateralis, rectus femoris, vastus intermedius), and vastus medialis - extends the leg at the knee joint. Rectus femoris also stabilizes the hip joint and aids the iliopsoas in thigh flexion.
Sensory Functions: The femoral nerve gives rise to two major sensory branches:
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Anterior cutaneous branches are derived from the femoral nerve's anterior division. They supply the anteromedial thigh skin.
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The saphenous nerve is a continuation of the femoral nerve's posterior division. It provides skin for the medial leg and foot.
What Conditions and Disorders Have an Impact on the Femoral Nerve?
The following conditions can harm or affect the femoral nerve:
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Femoral Nerve Neuropathy: It is also known as femoral nerve dysfunction. Neuropathy is a medical term that describes nerve damage. Mononeuropathy refers to damage to only one femoral nerve.
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Meralgia Paresthetica: It occurs as a result of pressure on the lateral femoral cutaneous nerve present in the thigh. It is a type of excruciating nerve compression syndrome.
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Pinched Nerve: Swollen tissues squeeze the nerve, resulting in a pinched nerve or nerve entrapment.
What Role Does the Femoral Nerve Play in the Knee-Jerk Reflex?
A knee-jerk reflex test is frequently performed as part of a routine physical examination. This simple test is used by healthcare providers to look for signs of potential peripheral nerve damage. During the examination:
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A soft rubber mallet is gently tapped on the patellar tendon below the kneecap by the doctor.
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The tap sends a message to the spine via the femoral nerve.
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The lower leg extends slightly.
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This is known as the Westphal sign. One may have a pinched nerve or nerve damage if there is little or no reaction.
What Are the Causes of Femoral Nerve Problems?
Tight clothing or a bulky toolbelt around the waist can cause problems with the lateral femoral cutaneous nerve. Other potential reasons include the following:
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Accidents and traumatic events.
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A broken leg, a broken hip, or pressure from a cast or splint.
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Surgical complications, such as hip replacement or hysterectomy, or femoral artery catheterization procedures.
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Herniated disk.
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Infections.
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Prolonged pressure on the nerve can be caused by pregnancy or obesity.
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Radiation treatment.
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Tumors, cysts, and hematomas are all examples of benign tumors (blood that leaks outside of blood vessels under the skin).
How Are Femoral Nerve Problems Diagnosed?
The doctor will examine and assess the symptoms. To make a diagnosis, the doctor may also advise the following tests:
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Electromyography and nerve conduction studies are used to analyze the electrical signals sent through the nervous system.
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MRI (magnetic resonance imaging) or X-rays are used to detect broken bones, tumors, and muscle damage.
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Ultrasound of the muscles to look for inflammation, tumors, and nerve damage.
What Is the Treatment for Femoral Nerve Problems?
Among the treatments for femoral nerve problems are:
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A nerve block involves injecting a numbing agent (anesthetic) around the nerve, preventing it from sending pain signals to the brain. This treatment may be required while recovering from a broken hip or hip replacement. Femoral nerve blocks are also used to numb the leg during knee surgery.
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To relieve nerve inflammation and pain, nonsteroidal anti-inflammatory drugs (NSAIDs) and steroid injections are used.
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Physical therapy to increase hip, leg, and knee flexibility and range of motion.
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Splints or casts support the leg and hip and relieve nerve pressure.
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Surgical removal of a tumor or repair or replacement of a damaged nerve (nerve transfer).
Conclusion
The femoral nerves aid in the bending and straightening of the hips and legs. Nerves transmit sensations from the leg to the brain. Healthcare providers sometimes use femoral nerve blocks to relieve pain in patients recovering from broken knees or knee replacement surgery. The femoral nerves can be damaged by trauma, surgery, or constriction (tightness) near the nerve, resulting in pain, weakness, or numbness. A lumbar pinched nerve or herniated disk can also cause nerve pain. If one has leg pain or difficulty walking, a healthcare provider must be consulted to determine the cause and seek care.
