Anatomy
Origin:
Lateral edge of costal groove of the rib above.
Insertion:
Superior surface of the rib below.
Key relations:
-Muscle fibres run in the opposite direction to the external intercostals i.e. run obliquely posteroinferiorly.
-Insert deep to the insertion of the external intercostals.
Functions
-Moves ribs inferiorly during expiration, thereby contracting the thoracic cavity.
-Maintains intercostals spaces during inspiration and expiration.
Supply
Nerve Supply:
Intercostal nerves T1 to T11.
Blood Supply:
Intercostal arteries.
Interested in taking our award-winning Pocket Anatomy app for a test drive?
