iliohypogastric nerve

It separates from the first lumbar nerve along with the larger iliohypogastric nerve.

Iliohypogastric nerve (blue)

It communicates with the iliohypogastric nerve of the lumbar plexus, and gives a branch to the Pyramidalis.

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

The internal oblique is innervated by the lower intercostal nerves, as well as the iliohypogastric nerve and the ilioinguinal nerve.

The ilioinguinal nerve closely follows the iliohypogastric nerve on the quadratus lumborum, but then passes below it to run at the level of the iliac crest.

The challenge is that the course of both ilioinguinal and iliohypogastric nerves is found to be consistent with that described in anatomical texts in only 42% of patients.

The iliohypogastric nerve runs anterior to the psoas major on its proximal lateral border to run laterally and obliquely on the anterior side of quadratus lumborum.

When harvesting bone from the anterior iliac crest (AICBG), the lateral cutaneous branch of the Iliohypogastric nerve (L1) is most likely to be injured.

The iliohypogastric nerve is the superior branch of the anterior ramus of spinal nerve L1 (one of the lumbar nerves) after this nerve receives fibers from T12 (subcostal nerve).

The ilioinguinal nerve then perforates the transversus abdominis near the anterior part of the iliac crest, and communicates with the iliohypogastric nerve between the transversus and the obliquus internus.

Anterior to the Quadratus lumborum are the colon, the kidney, the Psoas major and (if present) psoas minor, and the diaphragm; between the fascia and the muscle are the twelfth thoracic, ilioinguinal, and iliohypogastric nerves.