external muscles definition
abdominal external oblique muscle n. A muscle with origin from the fifth to twelfth ribs, with insertion into the anterior lateral lip of the iliac crest, the inguinal ligament, and the anterior layer of the sheath of the rectus muscle of the abdomen, with nerve supply from the ventral branches of the lower thoracic nerves, and whose action diminishes the capacity of the abdomen and draws the chest down.