Femoral branch of genitofemoral nerve

At a glance

English

Femoral branch of genitofemoral nerve

Latin (TA2)

Ramus femoralis nervi genitofemoralis

System

Nerve

Region

Lower limb

Side

Paired, left and right

About the femoral branch of genitofemoral nerve

The genitofemoral nerve, made of fibres from L1 and L2, crosses the front of psoas major and divides into a genital branch and a femoral branch. The femoral branch, sometimes called the lumboinguinal nerve, is the lateral of the two and is purely sensory. It should not be confused with the femoral nerve itself, a much larger branch of the same lumbar plexus that runs nearby.

From the division the branch descends on psoas, lateral to the external iliac artery, and passes behind the inguinal ligament into the thigh. There it travels inside the femoral sheath, in its lateral compartment, on the outer side of the femoral artery. A little below the ligament it leaves the sheath by piercing its front wall or passing through the cribriform fascia that covers the saphenous opening in the fascia lata. It then becomes subcutaneous and spreads to the skin.

Its territory is a small oval of skin over the upper part of the femoral triangle, just below the middle of the inguinal ligament, on the front of the upper thigh. On its way it may send a twig to the femoral artery, and its fibres can join the cutaneous branches of the femoral nerve and the ilioinguinal nerve, which supply neighbouring skin, so the borders between their territories vary from person to person.

Touching the skin of this upper inner thigh area is the afferent side of a superficial reflex that tests the L1 and L2 segments, while the efferent side runs in the genital branch. The femoral branch can be injured during operations in the groin, such as hernia repair, femoral artery catheterisation or vascular surgery, and in laparoscopic surgery on the back wall of the abdomen near psoas. Damage causes numbness or burning pain over the upper front of the thigh. Because the ilioinguinal, iliohypogastric and genitofemoral nerves overlap here, groin pain after surgery can be hard to trace to one nerve, and diagnostic blocks are sometimes used to sort them out.

Course and supply

Arises from

The genitofemoral nerve (L1-L2), dividing on the anterior surface of psoas major.

Ends in

Passes under the inguinal ligament within the lateral part of the femoral sheath, pierces the sheath or cribriform fascia, and ends in the skin below the middle of the inguinal ligament.

Supplies

Sensory to the skin over the upper part of the femoral triangle; the afferent limb of a superficial reflex of the upper thigh.