INTERNAL ABDOMINAL OBLIQUE

ORIGIN
Lumbar fascia, anterior two thirds of iliac crest and lateral two thirds of inguinal ligament
INSERTION
Costal margin, aponeurosis of rectus sheath (anterior and posterior ), conjoint tendon to pubic crest and pectineal line
ACTION
Supports abdominal wall, assists forced respiration, aids raising intra-abdominal pressure and, with muscles of other side , abducts and rotates trunk. Conjoint tendon supports posterior wall of inguinal canal
NERVE
Anterior primary rami (T7-12) (conjoint tendon ilioinguinal nerve (L1))