The genitofemoral nerve is a mixed branch of the

lumbar plexus The lumbar plexus is a web of nerves (a nerve plexus) in the lumbar region of the body which forms part of the larger lumbosacral plexus. It is formed by the divisions of the first four lumbar nerves (L1–L4) and from contributions of the su ...

derived from

anterior rami The ventral ramus (: rami) (Latin for 'branch') is the anterior division of a spinal nerve. The ventral rami supply the antero-lateral parts of the trunk and the limbs. They are mainly larger than the dorsal rami. Shortly after a spinal nerve e ...

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 ...

L1–L2. It splits into a genital branch and a femoral branch. It provides sensory innervation to the upper anterior thigh, as well as the skin of the anterior

scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...

in males and

mons pubis In human anatomy, and in mammals in general, the ''mons pubis'' or pubic mound (also known simply as the mons , and known specifically in females as the ''mons Venus'' or ''mons veneris'') is a rounded mass of fatty tissue found over the pubic s ...

in females. It also provides motor innervation to the cremaster muscle (via its genital branch).

Structure

Origin

The genitofemoral nerve is a branch of the

. It is derived from the

L1–L2. It coalesces within the substances of the psoas major muscle.

Course

It passes downwards, pierces the

psoas major The psoas major ( or ; from ) 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 iliopsoas. In other animals, this muscle is e ...

and emerges from its anterior surface. The nerve divides into two branches, the genital branch and the

lumboinguinal nerve The lumboinguinal nerve, also known as the femoral or crural branch of genitofemoral, is a nerve in the abdomen. The lumboinguinal nerve is a branch of the genitofemoral nerve. The "femoral" part supplies skin to the femoral triangle area. Stru ...

also known as the femoral branch, both of which then continue downwards and medially to the inguinal and femoral canal respectively.

Branches

Genital branch

The genital branch continues downward on the surface of the psoas major muscle, then enters the

inguinal canal The inguinal canal is a passage in the anterior abdominal wall on each side of the body (one on each side of the midline), which in males, convey the spermatic cords and in females, the round ligament of the uterus. The inguinal canals are lar ...

through the

deep inguinal ring The inguinal canal is a passage in the anterior abdominal wall on each side of the body (one on each side of the midline), which in males, convey the spermatic cords and in females, the round ligament of the uterus. The inguinal canals are large ...

. In men, the genital branch supplies the cremaster and scrotal skin. In women, the genital branch accompanies the

round ligament of uterus The round ligament of the uterus is a ligament that connects the uterus to the labia majora. It originates at the junction of the uterus and uterine tube. It passes through the inguinal canal to insert at the labium majus. The two round ligame ...

, terminating in and innervating the skin of the

and

labia majora In primates, and specifically in humans, the labia majora (: labium majus), also known as the outer lips or outer labia, are two prominent Anatomical terms of location, longitudinal skin folds that extend downward and backward from the mons pubis ...

Femoral branch

The femoral branch passes underneath the

inguinal ligament The inguinal ligament (), also known as Poupart's ligament or groin ligament, is a band running from the pubic tubercle to the anterior superior iliac spine. It forms the base of the inguinal canal through which an indirect inguinal hernia may ...

, travelling through the lateral muscular compartment of 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 vertica ...

where it innervates skin of the upper leg. Passing through the

cribriform fascia The cribriform fascia (also known as the fascia cribrosa, or Hesselbach's fascia) is the portion of the superficial layer of the deep fascia of leg which extends between the sartorius muscle, adductor longus muscle, and inguinal ligament to form ...

of the

saphenous opening In anatomy, the saphenous opening (saphenous hiatus, also fossa ovalis) is an oval opening in the upper mid part of the fascia lata of the thigh. It lies 3–4 cm below and lateral to the pubic tubercle and is about 3 cm long and 1.5 ...

of the fascia lata of the thigh, it then supplies the skin of the upper, anterior and medial side of thigh.

Variation

The genitofemoral nerve typically pierces and passes through the

muscle before bifurcating into a genital branch and a femoral branch midway along its anterior surface. In approximately 25% of cases, the genitofemoral nerve splits into these branches ''before'' it enters the

or ''within'' the muscle belly of

(with fibers of the

separating the genital and femoral branches). Usually this variation causes the split to be occur earlier in the genitofemoral nerve, at the upper rather than mid-portion of the anterior surface of the

Embryology

The genitofemoral nerve is formed in the midsection of the psoas muscle by the union of branches from the anterior rami of L1 and L2 nerve roots

Function

The genitofemoral nerve is responsible for both the sensory (femoral branch) and motor portions (genital branch) of the

cremasteric reflex The cremasteric reflex is a superficial (i.e., close to the skin's surface) reflex observed in human males. This reflex is elicited by lightly stroking or poking the superior and medial (inner) part of the thigh—regardless of the direction of ...

, which describes contraction of the

cremasteric muscle The cremaster muscle is a paired structure made of thin layers of striated and smooth muscle that covers the testicles and the spermatic cords in human males. It consists of the lateral and medial parts. Cremaster is an involuntary muscle, respo ...

when the skin of the superior medial part of the thigh is touched.

Additional images

File:Gray824.png, Deep and superficial dissection of the lumbar plexus. File:Slide6w.JPG, Genitofemoral nerve

References

External links

* - "Inguinal Region, Scrotum and Testes: Layers of the spermatic cord" * - "Muscles and nerves of the posterior abdominal wall." * () {{Authority control Nerves of the lower limb and lower torso