Iliohypogastric nerve (L1)

Nerves · L1

Emerges from the upper lateral border of psoas, crosses quadratus lumborum, pierces transversus abdominis above the iliac crest and runs between transversus and internal oblique towards the pubis, parallel to and above the ilioinguinal nerve.

Traced from the start

  1. L1 anterior ramusL2 anterior ramus
  2. Upper lumbar branches (L1–L2)
  3. Iliohypogastric nerve (L1)

Detail

Motor
Internal oblique and transversus abdominis, including the lower fibres that form the conjoint tendon
Sensory
Lateral cutaneous branch: posterolateral gluteal skin. Anterior cutaneous branch: suprapubic (hypogastric) skin above the superficial inguinal ring

When it goes wrong

Cut in a low gridiron appendicectomy incision, a Pfannenstiel incision or anterior iliac crest bone harvest

Numb suprapubic or lateral gluteal skin; a denervated conjoint tendon weakens the posterior wall and predisposes to a direct inguinal hernia

Practise this structure

2 questions in the bank tagged Abdominal Wall.