Anterior Cutaneous Nerves of the Abdomen

nervi cutanei abdominales anteriores

The anterior cutaneous nerves of the abdomen are the medial terminal branches of the thoracic intercostal nerves T7-T12, which pierce the posterior rectus sheath and the rectus abdominis to emerge through the anterior sheath as the anterior cutaneous branches. They supply the anterior abdominal skin in segmental dermatomal bands, with T10 corresponding to the umbilical level and T12 to the suprapubic region.

Region: Abdomen

Clinical Relevance

Clinical Notes

Anterior cutaneous nerve entrapment syndrome (ACNES) is an under-recognised cause of chronic abdominal pain, where the anterior cutaneous nerve is entrapped as it pierces the anterior rectus sheath at the lateral rectus edge. The pain is sharp, lateralised, and reproduced by the Carnett test (pain increases with abdominal wall contraction). Trigger point injection or ultrasound-guided nerve block at the entrapment site is diagnostic and therapeutic. Chronic ACNES is treated by surgical neurotomy. The anterior cutaneous nerves are at risk in paramedian and midline laparotomy closures if sutures are placed too laterally.

Pathology

Common Injuries & Conditions

Anterior Cutaneous Nerve Entrapment Syndrome

Entrapment of T10-T12 anterior cutaneous nerves at the lateral rectus sheath edge produces chronic abdominal wall pain that is superficial, lateralised, and worsened by Carnett test; distinguished from visceral pain by the positive Carnett test and reproduced by pressure at the nerve entry point, managed by injection and if persistent by surgical neurotomy.