The femoral nerve, the largest branch of the lumbar plexus, arises from the dorsal divisions of the ventral rami of the second, third, and fourth lumbar nerves

Lumbar nerves

The lumbar nerves are the five spinal nerves emerging from the lumbar vertebrae. They are divided into posterior and anterior divisions.-Posterior divisions:...

. It descends through the fibers of the psoas major muscle

Psoas major muscle

-External links: - "Posterior Abdominal Wall: Muscles of the Posterior Abdominal Wall"* *...

, emerging from the muscle at the lower part of its lateral border, and passes down between it and the iliacus muscle

Iliacus muscle

The iliacus is a flat, triangular muscle which fills the iliac fossa.- Course :The iliacus arises from the iliac fossa on the interior side of the hip bone, and also from the region of the anterior inferior iliac spine...

, behind the iliac fascia

Iliac fascia

The iliac fascia is a fascia in the pelvic area of the human body.It has the following connections:* laterally, to the whole length of the inner lip of the iliac crest....

; it then runs beneath the inguinal ligament

Inguinal ligament

The inguinal ligament is a band running from the pubic tubercle to the anterior superior iliac spine. Its anatomy is very important for operating on hernia patients.-Anatomy:...

, into the thigh

Thigh

In humans the thigh is the area between the pelvis and the knee. Anatomically, it is part of the lower limb.The single bone in the thigh is called the femur...

, and splits into an anterior and a posterior division. Under the inguinal ligament

Inguinal ligament

The inguinal ligament is a band running from the pubic tubercle to the anterior superior iliac spine. Its anatomy is very important for operating on hernia patients.-Anatomy:...

, it is separated from the femoral artery

Femoral artery

The femoral artery is a general term comprising a few large arteries in the thigh. They begin at the inguinal ligament and end just above the knee at adductor canal or Hunter's canal traversing the extent of the femur bone....

 by a portion of the psoas major.

In the abdomen

Within the abdomen the femoral nerve gives off small branches to the iliacus muscle, and a branch which is distributed upon the upper part of the femoral artery (a continuation of the external iliac artery); the latter branch may arise in the thigh.

Anterior division

In the thigh the anterior division of the femoral nerve gives off anterior cutaneous and muscular branches.

• Anterior cutaneous branches
  Anterior cutaneous branches of the femoral nerve
  The anterior cutaneous branches of the femoral nerve consist of the following nerves: intermediate cutaneous nerve and medial cutaneous nerve.-Intermediate cutaneous nerve of thigh:...
  
  : The anterior cutaneous branches comprise the following nerves: intermediate cutaneous nerve, medial cutaneous nerve and lateral cutaneous nerve.

• Muscular branches (rami musculares): The nerve to the Pectineus arises immediately below the inguinal ligament, and passes behind the femoral sheath to enter the anterior surface of the muscle; it is often duplicated. The nerve to the Sartorius
  Sartorius muscle
  The Sartorius muscle – the longest muscle in the human body – is a long thin muscle that runs down the length of the thigh. Its upper portion forms the lateral border of the femoral triangle.-Origin and insertion:...
  
   arises in common with the intermediate cutaneous.

Posterior division

The posterior divisiThe muscular branches supply the four parts of the Quadriceps femoris.

• • The branch to the Rectus femoris enters the upper part of the deep surface of the muscle, and supplies a filament to the hip-joint.
  • The branch to the Vastus lateralis, of large size, accompanies the descending branch of the lateral femoral circumflex artery
    Lateral femoral circumflex artery
    The lateral circumflex femoral artery is an artery in the upper thigh.-Structure:...
    
     to the lower part of the muscle. It gives off an articular filament to the knee-joint.
  • The branch to the Vastus medialis
    Vastus medialis
    The vastus medialis , often called the 'teardrop' muscle, is a medially located muscle of the quadriceps.-Function:The vasti appear to act largely in a co-ordinated manner throughout the control of knee extension...
    
     descends lateral to the femoral vessels in company with the saphenous nerve
    Saphenous nerve
    The saphenous nerve is the largest cutaneous branch of the femoral nerve.-Path:It approaches the femoral artery where this vessel passes beneath the sartorius, and lies in front of the artery, behind the aponeurotic covering of the adductor canal, as far as the opening in the lower part of the...
    
    . It enters the muscle about its middle, and gives off a filament, which can usually be traced downward, on the surface of the muscle, to the knee-joint.
  • The branches to the Vastus intermedius, two or three in number, enter the anterior surface of the muscle about the middle of the thigh; a filament from one of these descends through the muscle to the Articularis genu and the knee-joint. The articular branch to the hip-joint is derived from the nerve to the Rectus femoris.

• The articular branches to the knee-joint are three in number.
  • One, a long slender filament, is derived from the nerve to the Vastus lateralis; it penetrates the capsule of the joint on its anterior aspect.
  • Another, derived from the nerve to the Vastus medialis
    Vastus medialis
    The vastus medialis , often called the 'teardrop' muscle, is a medially located muscle of the quadriceps.-Function:The vasti appear to act largely in a co-ordinated manner throughout the control of knee extension...
    
    , can usually be traced downward on the surface of this muscle to near the joint; it then penetrates the muscular fibers, and accompanies the articular branch of the highest genicular artery, pierces the medial side of the articular capsule, and supplies the synovial membrane.
  • The third branch is derived from the nerve to the Vastus intermedius.

External links

- "Femoral nerve dysfunction" (includes illustration) - "Posterior Abdominal Wall: Nerves of the Lumbar Plexus"

• Diagram at nysora.com