iliohypogastricus

The iliohypogastric nerve is a branch of the lumbar plexus, typically arising from the ventral ramus of the first lumbar spinal nerve (L1), with occasional contributions from the twelfth thoracic nerve (T12). It provides motor innervation to the abdominal wall muscles and sensory input to the skin of the lower abdomen and suprapubic region.

After its origin, the nerve runs laterally across the posterior abdominal wall, usually between the internal oblique and transversus abdominis muscles. It travels toward the iliac crest near the anterior superior iliac spine, and it may share a common trunk with the ilioinguinal nerve in some individuals. Its course places it at risk during procedures involving the lower abdominal wall or groin.

The iliohypogastric nerve has motor branches to the internal oblique and transversus abdominis muscles, contributing to the stabilization of the abdominal wall. Its cutaneous branches supply sensation to the skin of the lower abdomen, particularly the suprapubic region, and may provide small areas of innervation to nearby skin. There is often overlap with the distribution of the ilioinguinal nerve, and the two nerves can communicate in some people.

Clinically, injury to the iliohypogastric nerve can occur during abdominal, groin, or obstetric procedures, leading to numbness or pain in the suprapubic area and weakness of abdominal wall muscles. Recognition of its course is important in surgical planning, nerve-sparing techniques, and during regional anesthesia or nerve- block procedures. Variations exist in origin, branching, and relationship to the ilioinguinal nerve.