Internal intercostal muscles
|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|
|Action:||hold ribs steady|
|Antagonist:||Intercostales externi muscles|
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.
- LUC inin
- -254803891 at GPnotebook
- SUNY Labs 18:03-0101 - "The Internal Intercostal Muscle"
- SUNY Figs 18:03-03 - "Transverse section of thorax."
- internal+intercostal+muscle at eMedicine Dictionary
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 As such, some of the information contained herein may be outdated.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.