Genitofemoral nerve

The genitofemoral nerve is a mixed branch of the lumbar plexus derived from anterior rami of lumbar nerves 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 males and mons pubis 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 lumbar plexus.<ref name="GRAYS2005" /> It is derived from the anterior rami of lumbar nerves L1–L2. It coalesces within the substances of the psoas major muscle.<ref name=":224">Template:Cite book</ref>

Course

It passes downwards, pierces the psoas major and emerges from its anterior surface. The nerve divides into two branches, the genital branch and the lumboinguinal nerve also known as the femoral branch,<ref name="GRAYS2005">Template:Cite book</ref> both of which then continue downwards and medially to the inguinal and femoral canal respectively.

Branches

Genital branch

{{#invoke:Labelled list hatnote|labelledList|Main article|Main articles|Main page|Main pages}} The genital branch continues downward on the surface of the psoas major muscle, then enters the inguinal canal through the deep inguinal ring.<ref name="GRAYS2005" />

In men, the genital branch supplies the cremaster and scrotal skin. In women, the genital branch accompanies the round ligament of uterus, terminating in and innervating the skin of the mons pubis and labia majora.<ref name="GRAYS2005" />

Femoral branch

The femoral branch passes underneath the inguinal ligament, travelling through the lateral muscular compartment of the femoral sheath where it innervates skin of the upper leg. Passing through the cribriform fascia of the saphenous opening of the fascia lata of the thigh, it then supplies the skin of the upper, anterior and medial side of thigh.<ref name= GRAYS2005 />

Variation

Template:Expand section The genitofemoral nerve typically pierces and passes through the psoas major 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 psoas major or within the muscle belly of psoas major (with fibers of the psoas major 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 psoas major.<ref>Template:Cite journal</ref>

Embryology

Template:Expand section 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, which describes contraction of the cremasteric muscle when the skin of the superior medial part of the thigh is touched.<ref name= GRAYS2005 /> Template:Rp

Additional images

• Gray824.png

  Deep and superficial dissection of the lumbar plexus.

• Slide6w.JPG

  Genitofemoral nerve

External links

• Template:SUNYAnatomyLabs - "Inguinal Region, Scrotum and Testes: Layers of the spermatic cord"
• Template:SUNYAnatomyFigs - "Muscles and nerves of the posterior abdominal wall."
• Template:NormanAnatomy (Template:NormanAnatomyFig)