Also called: obliquus externus abdominis
The external oblique is the largest and most superficial of the lateral abdominal wall muscles. It arises from the outer surfaces of the lower eight ribs and inserts on the iliac crest and linea alba through an aponeurosis. The lower thoracic nerves supply it, and it flexes and rotates the trunk and compresses the abdomen.
| Origin | External surfaces of ribs 5 to 12. |
|---|---|
| Insertion | Anterior half of the iliac crest, pubic tubercle and linea alba through the external oblique aponeurosis. |
| Innervation | Thoracoabdominal nerves (T7-T11) and the subcostal nerve (T12). |
| Blood supply | Lower posterior intercostal, subcostal and deep circumflex iliac arteries. |
| Action | Both sides flex the trunk and compress the abdomen; one side rotates the trunk to the opposite side. |
3D model: BodyParts3D (CC BY 4.0), adult male reference anatomy. Highlighted structure shown with nearby bones for context.
The lower border of its aponeurosis forms the inguinal ligament, and the superficial inguinal ring is an opening in the aponeurosis.
Downward and medially, in the direction of putting hands in your pockets.
The lower border of the external oblique aponeurosis.
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