INTERNAL ABDOMINAL OBLIQUE
| ORIGIN Lumbar fascia, anterior two thirds of iliac crest and lateral two thirds of inguinal ligament |
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| INSERTION Costal margin, aponeurosis of rectus sheath (anterior and posterior ), conjoint tendon to pubic crest and pectineal line |
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| 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 |
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| NERVE Anterior primary rami (T7-12) (conjoint tendon ilioinguinal nerve (L1)) |