abdominal internal oblique muscle

n.

1. A muscle with origin from the iliac fascia deep to the lateral part of the inguinal ligament, to the anterior half of the crest of the ilium, and to the lumbar fascia, with insertion into the tenth to twelfth ribs and the sheath of the rectus muscle of the abdomen, with nerve supply from the lower thoracic nerve, and whose action diminishes the capacity of the abdomen and bends the chest forward.