Iliohypogastric nerve


The iliohypogastric nerve is a nerve that originates from the lumbar plexus that supplies sensation to skin over the lateral gluteal and hypogastric regions and motor to the internal oblique and transverse abdominal muscles.
The nerve emerges from the psoas major in the outer part of its upper border, and crosses in front of the quadratus lumborum to the iliac crest, running behind the kidneys. Near the iliac crest the iliohypogastric nerve then pierces through the transversus abdominis and divides between that muscle and the internal oblique muscle into a lateral and an anterior cutaneous branch.

Branches

The iliohypogastric nerve originates from the superior branch of the anterior ramus of spinal nerve L1 after this nerve receives fibers from T12 via the subcostal nerve. The inferior branch is the ilioinguinal nerve.

Lateral cutaneous branch

The lateral cutaneous branch pierces the internal and external oblique muscles immediately above the iliac crest and is distributed to the skin of the gluteal region, behind the lateral cutaneous branch of the subcostal nerve; the size of this branch bears an inverse proportion to that of the lateral cutaneous branch of the subcostal nerve.
When harvesting bone from the anterior iliac crest, the lateral cutaneous branch of the Iliohypogastric nerve is most likely to be injured.

Anterior cutaneous branch

The anterior cutaneous branch continues onward between the abdominal internal oblique and transverse muscles.
It then pierces the internal oblique, becomes cutaneous by perforating the aponeurosis of the external oblique about 2.5 cm above the subcutaneous inguinal ring, and is distributed to the skin of the hypogastric region.

Communication

The iliohypogastric nerve communicates with the subcostal nerve and ilioinguinal nerves.