Internal intercostal muscles - Musculi intercostales interni

Anatomical hierarchy

General terms > Myology > Muscles of thorax > Internal intercostal muscles

Anatomical children



The internal intercostal muscles (Musculi intercostales interni)are fibers that run from the cranial aspect of tone rib to the caudal aspect of the preceding rib in a cranioventral direction (perpendicular to the fibers of the external intercostal muscles). These muscles lie lateral to the intercostal nerve and assist expiration.

In dogs:

Origin: lower border of ribs

Insertion: upper border of rib below

Action: expiration, to draw the ribs together so as to narrow the thoracic cavity

Nerve: Muscular branches of intercostal nerves one to twelve.

Text by Antoine Micheau, MD - Copyright IMAIOS
Miller's Anatomy of the Dog, 4th Edition - Evans & de Lahunta- Elsevier
Illustrated Veterinary Anatomical Nomenclature - 3rd edittion - Gheorghe M. Constantinescu, Oskar Schaller - Enke


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