Muscle
External oblique
Outermost flat abdominal muscle
High-yield
Fibres run "hands in your pockets"; its aponeurosis forms the inguinal ligament. Rotates trunk to the opposite side.
Overview
The largest and most superficial flat abdominal muscle, its fibres running inferomedially ('hands in pockets'), forming the inguinal ligament inferiorly.
Reference facts
- Origin
- External surfaces of ribs 5-12
- Insertion
- Linea alba, pubic tubercle, and anterior half of the iliac crest
- Action
- Compresses the abdomen; flexes and rotates the trunk to the contralateral side
- Innervation
- Thoracoabdominal nerves (T7-T12) and subcostal nerve
- Blood supply
- Lower posterior intercostal / subcostal arteries
Frequently asked questions
What does the external oblique do?
The external oblique compresses the abdomen; flexes and rotates the trunk to the contralateral side.
What nerve innervates the external oblique?
The external oblique is innervated by the thoracoabdominal nerves (T7-T12) and subcostal nerve.
Where does the external oblique attach?
The external oblique originates from the external surfaces of ribs 5-12 and inserts on the linea alba, pubic tubercle, and anterior half of the iliac crest.
What is the blood supply of the external oblique?
The external oblique is supplied by the lower posterior intercostal / subcostal arteries.