The femoral nerve is a nerve in the

thigh In human anatomy, the thigh is the area between the hip (pelvis) and the knee. Anatomically, it is part of the lower limb. The single bone in the thigh is called the femur. This bone is very thick and strong (due to the high proportion of bone ...

that supplies skin on the upper thigh and inner leg, and the muscles that extend the knee.

Structure

The femoral nerve is the major nerve supplying the anterior compartment of the thigh. It is the largest branch of the

lumbar plexus The lumbar plexus is a web of nerves (a nervous plexus) in the lumbar region of the body which forms part of the larger lumbosacral plexus. It is formed by the Ventral ramus of spinal nerve, divisions of the first four lumbar nerves (L1-L4) and ...

, and arises from the dorsal divisions of the ventral rami of the second, third, and fourth

lumbar nerves The lumbar nerves are the five pairs of spinal nerves emerging from the lumbar vertebrae. They are divided into posterior and anterior divisions. Structure The lumbar nerves are five spinal nerves which arise from either side of the spinal cord b ...

(L2, L3, and L4). The nerve enters Scarpa's triangle by passing beneath the inguinal ligament, just lateral to the

femoral artery The femoral artery is a large artery in the thigh and the main arterial supply to the thigh and leg. The femoral artery gives off the deep femoral artery or profunda femoris artery and descends along the anteromedial part of the thigh in the fem ...

. In the thigh, the nerve lies in a groove between

iliacus muscle The iliacus is a flat, triangular muscle which fills the iliac fossa. It forms the lateral portion of iliopsoas, providing flexion of the thigh and lower limb at the acetabulofemoral joint. Structure The iliacus arises from the iliac fossa ...

and

psoas major muscle The psoas major ( or ; from grc, ψόᾱ, psóā, muscles of the loins) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the il ...

, outside the

femoral sheath The femoral sheath (also called the crural sheath) is a funnel-shaped downward extension of abdominal fascia within which the femoral artery and femoral vein pass between the abdomen and the thigh. The femoral sheath is subdivided by two vertical ...

, and lateral to the femoral artery. After a short course of about 4 cm in the thigh, the nerve is divided into anterior and posterior divisions, separated by

lateral femoral circumflex artery The lateral circumflex femoral artery, also known as the lateral femoral circumflex artery, or the external circumflex artery, is an artery in the upper thigh. It is usually a branch of the profunda femoris artery, and produces three branches. It ...

. The branches are shown below:

Muscular branches

* The nerve to the

pectineus muscle The pectineus muscle (, from the Latin word ''pecten'', meaning comb) is a flat, quadrangular muscle, situated at the anterior (front) part of the upper and medial (inner) aspect of the thigh. The pectineus muscle is the most anterior adductor o ...

arises immediately above the inguinal ligament from the medial side of the femoral nerve, and passes behind the femoral sheath to enter the anterior surface of the muscle. * Anterior division supplies the

sartorius muscle The sartorius muscle () is the longest muscle in the human body. It is a long, thin, superficial muscle that runs down the length of the thigh in the Anterior compartment of thigh, anterior compartment. Structure The sartorius muscle originates f ...

* Posterior division supplies the

rectus femoris muscle The rectus femoris muscle is one of the four quadriceps muscles of the human body. The others are the vastus medialis, the vastus intermedius (deep to the rectus femoris), and the vastus lateralis. All four parts of the quadriceps muscle attach t ...

, the three vasti (

vastus medialis muscle The vastus medialis (vastus internus or teardrop muscle) is an extensor muscle located medially in the thigh that extends the knee. The vastus medialis is part of the quadriceps muscle group. Structure The vastus medialis is a muscle present ...

vastus lateralis muscle The vastus lateralis (), also called the vastus externus, is the largest and most powerful part of the quadriceps femoris, a muscle in the thigh. Together with other muscles of the quadriceps group, it serves to extend the knee joint, moving the l ...

, and

vastus intermedius muscle The vastus intermedius () (Cruraeus) arises from the front and lateral surfaces of the body of the femur in its upper two-thirds, sitting under the rectus femoris muscle and from the lower part of the lateral intermuscular septum. Its fibers en ...

), and

articularis genus muscle The articularis genus (also known as the subcrureus muscle) is a small skeletal muscle located anteriorly on the thigh just above the knee. Structure It arises from the anterior surface of the lower part of the body of the femur, deep to the v ...

. The articularis genus is supplied by a branch of the nerve to vastus intermedius.

Cutaneous branches

* The anterior division gives off anterior cutaneous branches: The anterior cutaneous branches are: the intermediate femoral cutaneous nerve and the medial femoral cutaneous nerve. * The posterior division gives off only one branch, which is the

saphenous nerve The saphenous nerve (long or internal saphenous nerve) is the largest cutaneous branch Cutaneous innervation refers to the area of the skin which is supplied by a specific cutaneous nerve. Dermatome (Anatomy), Dermatomes are similar; however, a ...

Articular branches

* Hip joint is supplied by nerve to the rectus femoris. * Knee joint is supplied by the nerves to the three vasti. The nerve to vastus medialis is particularly thick because it contains the proprioceptive fibres from the knee joint. This is in accordance to the

Hilton's law Hilton's law, espoused by John Hilton in a series of medical lectures given in 1860–1862, is the observation that in the study of anatomy, the nerve supplying the muscles extending directly across and acting at a given joint not only supplies the ...

Vascular branches

* Branches to the femoral artery and its branches.

Clinical significance

Signals from the femoral nerve and its branches can be blocked to interrupt transmission of pain signal from the innervation area, by performing a regional nerve blockage. Some of the nerve blocks that work by affecting the femoral nerve are the

femoral nerve block A femoral nerve block is a Local anesthetic nerve block, nerve block that uses local anesthetic to achieve analgesia in the leg. The block works by affecting the femoral nerve. A femoral nerve block (FNB) results in anesthesia of the skin and mus ...

, the

fascia iliac block Fascia iliaca blocks (FIC, FICB) is a local anesthetic nerve block, a type of regional anesthesia technique, used to provide analgesia or anaesthesia to the hip and thigh. FICB can performed by using ultrasound or with a loss of resistance t ...

and the 3-in-1 nerve block. Femoral nerve blocks are very effective. During pelvic

surgery Surgery ''cheirourgikē'' (composed of χείρ, "hand", and ἔργον, "work"), via la, chirurgiae, meaning "hand work". is a medical specialty that uses operative manual and instrumental techniques on a person to investigate or treat a pat ...

and

abdominal surgery The term abdominal surgery broadly covers surgical procedures that involve opening the abdomen (laparotomy). Surgery of each abdominal organ is dealt with separately in connection with the description of that organ (see stomach, kidney, liver, etc ...

, the femoral nerve must be identified early on to protect it from

iatrogenic Iatrogenesis is the causation of a disease, a harmful complication, or other ill effect by any medical activity, including diagnosis, intervention, error, or negligence. "Iatrogenic", ''Merriam-Webster.com'', Merriam-Webster, Inc., accessed 2 ...

nerve injury Nerve injury is an injury to nervous tissue. There is no single classification system that can describe all the many variations of nerve injuries. In 1941, Seddon introduced a classification of nerve injuries based on three main types of nerve f ...

. The femoral nerve stretch test can be performed to identify the compression of spinal nerve roots. The test is positive if

pain Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling that associated with, ...

increases.

Additional images

File:Gray546.png, Structures passing behind the right inguinal ligament File:Gray827.png, Nerves of the right leg. File:Slide6888.JPG, Femoral nerve.Deep dissection. File:Slide8AAA.JPG, Femoral nerve.Deep dissection.

References

External links

* * - "Femoral nerve dysfunction" (includes illustration) * - "Posterior Abdominal Wall: Nerves of the Lumbar Plexus" * * *
arteries-nerves%20LE/nerves1
at the

Dartmouth Medical School The Geisel School of Medicine at Dartmouth is the graduate medical school of Dartmouth College in Hanover, New Hampshire. The fourth oldest medical school in the United States, it was founded in 1797 by New England physician Nathan Smith. It is o ...

's Department of Anatomy {{Authority control Nerves of the lower limb and lower torso