Intercostales interni muscles

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Intercostales interni muscle

Deep muscles of the chest and front of the arm, with the boundaries of the axilla. (Intercostalis internus labeled at bottom left.)

Posterior surface of sternum and costal cartilages, showing Transversus thoracis. (Intercostalis internus visible at left.)
Latin	musculi intercostales interni
Gray's	subject #117 403
Origin:	rib - inferior border
Insertion:	rib - superior border
Blood:
Nerve:	intercostal nerves
Action:	hold ribs steady
Dorlands/Elsevier	m_22/12549376

The Intercostales interni (Internal intercostals) are eleven in number on either side. They commence anteriorly at the sternum, in the interspaces between the cartilages of the true ribs, and at the anterior extremities of the cartilages of the false ribs, and extend backward as far as the angles of the ribs, whence they are continued to the vertebral column by thin aponeuroses, the posterior intercostal membranes.

Each arises from the ridge on the inner surface of a rib, as well as from the corresponding costal cartilage, and is inserted into the upper border of the rib below.

Their fibers are also directed obliquely, but pass in a direction opposite to those of the Intercostales externi.

[edit] Additional images

The Obliquus internus abdominis.

Diagram of the course and branches of a typical intercostal nerve.

Thoracic portion of the sympathetic trunk.

[edit] External links

LUC inin
GPnotebook -254803891
SUNY Labs 18:03-0101 - "The Internal Intercostal Muscle"
SUNY Figs 18:03-03 - "Transverse section of thorax."

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

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