External intercostal muscles
|Intercostales externi muscle|
|Deep muscles of the chest and front of the arm, with the boundaries of the axilla. (Intercostalis externus labeled at bottom center.)|
|The Obliquus internus abdominis. (Intercostalis externus labeled at top center.)|
|Latin||musculi intercostales externi|
|Gray's||subject #117 403|
|Antagonist:||intercostales interni muscles|
The Intercostales externi (External intercostals) are eleven in number on either side.
They extend from the tubercles of the ribs behind, to the cartilages of the ribs in front, where they end in thin membranes, the anterior intercostal membranes, which are continued forward to the sternum.
Each arises from the lower border of a rib, and is inserted into the upper border of the rib below. In the two lower spaces they extend to the ends of the cartilages, and in the upper two or three spaces they do not quite reach the ends of the ribs.
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