External oblique
Musculus obliquus externus abdominis
MuscularSuperficial musclesWhole bodyLeft and right
View left in 3D View right in 3D
- What it is
- Largest and most superficial flat abdominal muscle. Fleshy digitations from the outer surfaces of ribs 5–12 (interlocking with serratus anterior and latissimus dorsi) run down and forwards ("hands in pockets") into a broad aponeurosis reaching the linea alba, pubic tubercle and anterior iliac crest; its folded lower edge is the inguinal ligament.
- Function
- Compresses the abdomen, flexes the trunk and rotates it to the opposite side; assists forced expiration.
- Size
- About 30 cm tall; fleshy part 5–7 mm thick.
- Clinical note
- Its aponeurosis forms the front wall of the inguinal canal, and the superficial inguinal ring is a split in it. The part covering rectus (anterior rectus sheath) is omitted here.