Femoral Nerve

Introduction[edit|edit source]

The femoral nerve is the largest nerve of thelumbar plexus. It originates from the dorsal divisions of the L2-L4 ventral rami. It has a role in motor and sensory processing in the lower limbs. It controls:

1. The majorhip flexor muscles, as well asknee extensionmuscles.
2. Sensation over the anterior and medial thigh, as well as medial leg down to the hallux (great toe).^[2]

Anatomy[edit|edit source]

In thePelvis

• The nerve emerges from behind the腰大肌肌肉to run laterally, deep to the iliacfasciaabove theiliacus muscle.
• Muscular branches are first given off to the psoas and then to the iliacus muscles (sometimes known together as theiliopsoasmuscle) before the nerve runs beneath theinguinal ligament.

It then enters the thigh

• It begins lateral to thefemoral artery(behind the inguinal ligament), dividing approximately 4 cm below the inguinal ligament into anterior and posterior divisions.
• 

  Femoral and lateral-femoral-cutaneous-nerves
  The anterior division gives rise to the medial and intermediate cutaneous nerves of the thigh and muscular branches to thesartoriusandpectineus muscles.
• The posterior division supplies the four heads of thequadriceps femoris(vastus medialis,vastus lateralis,vastus intermediusandrectus femoris)^[3]and then continues along the medial border of the calf as the saphenous nerve.
• The saphenous nerve is the largest and longest branch of the femoral nerve and supplies theskinover the medial side of the leg.

Articular Supply

• The femoral nerve also innervates the capsule of the hip joint and allows forproprioceptivefeedback about the joint.^[4]
• The knee joint is supplied by the nerves to the three vasti. The nerve to the vastus medialis contains numerous proprioceptive fibres from the knee joint, accounting for the thickness of the nerve.^[5]

Note: The lateral thigh is not supplied by the femoral nerve but is innervated by the lateral femoral cutaneous nerve , which is derived directly from the lumbar plexus, receiving innervation from the L2–L3 nerve roots.^[6]

Femoral Triangle[edit|edit source]

The following structures pass throughthe femoral triangle:

• Femoral nerve- Which innervates the anterior compartment of the thigh
• Femoral sheath containing:Femoral arteryand branches -Arterial供应大部分下肢; Femoralvein- The great saphenous vein drains into the femoral vein within the triangle; Femoral canal - Containslymphnodes and vessels^[7]

Physiotherapy Relevance[edit|edit source]

Femoral nerve damage (also referred to as femoral nerve dysfunction orneuropathy), can occur from an injury or prolonged compression. Typically, damage and dysfunction of the femoral nerve are associated with the leg weakness and sensation changes.
InjuryInjury of the femoral is uncommon but may be injured by a stab, gunshot wounds, or apelvic fracture. The femoral nerve can be damaged during penetrating trauma to the thigh. It can also be damaged duringhip replacementoperations, particularly the anterior approach (not commonly used) where the nerve can be stretched and damaged. Listed here are the characteristic clinical features:

Motor Loss

• Poor flexion of the hip, because of paralysis of the iliacus, psoas and sartorius muscles.
• Inability to extend the knee, because of paralysis of the quadriceps femoris.

Sensory impairment

• Sensory decline over the anterior and medial aspects of the thigh, as a result of engagement of the intermediate and lateral cutaneous nerves of the thigh.
• Sensory loss on the medial side of the leg and foot up to the ball of the great toe (first metatarsophalangeal joint), because of engagement of the saphenous nerve.^[8]

Apart from direct injury aside the femoral nerve damage can be caused by a number of other factors.

• Certain medical conditions egdiabetes, can damage this nerve due to impaired metabolic functioning, and is common.
• Other mediating factors includefracturing the pelvis, internal bleeding, or oxygen deprivation to the nerve due to becoming encased in a tumor or being subjected to pressure by the presence of a tumor.^[9]

Other relevant issues

• Patellar Tendon Reflex:The femoral nerve is responsible for the patellar tendonreflex(tests L3-L4 spinal component
• Femoral nerve block:Femoral nerve block (in combination withsciatic nerveblock) may be indicated in patients requiring lower limbsurgerywho cannot tolerate a general anaesthetic. A femoral nerve block can also be used as peri- and post-operative analgesia for patients with afractured neck of femurwho cannot tolerate particular analgesics.
• Femoral nerve tension test

Viewing[edit|edit source]

Below is a 6 minute video on the femoral nerve.^[10]

References[edit|edit source]