External intercostals

External intercostals

Anatomy

Origin:
Inferior margin of the rib above i.e. ribs 1 to 11.

Insertion:
Superior surface of the rib below i.e. ribs 2 to 12.

Key relations:
-Muscle fibres run obliquely anteroinferiorly.
-Most superficial intercostal muscle.

Functions

-Moves ribs superiorly during inspiration, thereby expanding the thoracic cavity.
-Maintains intercostals spaces during inspiration and expiration.

Supply

Nerve Supply:
Intercostal nerves T1 to 11.

Blood Supply:
Intercostal arteries.

Interested in taking our award-winning Pocket Anatomy app for a test drive?