Internal intercostal muscles - Musculi intercostales interni

Anatomical hierarchy

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



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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