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Internal intercostal muscles
Last reviewed: 19.11.2021
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Internal intercostal muscles (mm. Intercostales interni) are located inward from the external intercostal muscles. They occupy the intercostal spaces, starting from the edge of the sternum (at the true ribs) and the anterior ends of the cartilages of the false ribs and to the corners of the ribs from the rear, where the inner intercostal membrane (membrane intercostalis interna) serves as a continuation . These muscles begin at the upper edge of the underlying rib and the corresponding costal cartilage and attach to the lower edge of the overlying rib within the rib groove.
The bunches of the internal intercostal muscles are directed obliquely from the bottom upwards and laterally at the posterior thoracic wall, upward and medially at the anterior wall. Internal intercostal muscles in relation to the beams of the external intercostal muscles are located almost at right angles. The internal bundles of these muscles are called the most internal intercostal muscles (mm., Intercostales intimi).
Function of internal intercostal muscles: the internal intercostal muscles lower the ribs, strengthen the sterno-rib joints.
Innervation of internal intercostal muscles: intercostal nerves (ThI-ThXI).
Blood supply of internal intercostal muscles: posterior intercostal arteries, intercostal branches of internal thoracic artery, muscular-diaphragmatic artery.
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