Innermost intercostal muscle
Layer of muscles of the ribs From Wikipedia, the free encyclopedia
The innermost intercostal muscle is a layer of intercostal muscles.[1] It may also be called the intima of the internal intercostal muscles.[2] It is the deepest muscular layer of the thorax,[3] with muscle fibres running vertically (in parallel with the internal intercostal muscles).[2] It is present only in the middle of each intercostal space, and often not present higher up the rib cage.[3] It lies deep to the plane that contains the intercostal nerves and intercostal vessels, and the internal intercostal muscles.[3][4] The diaphragm is continuous with the innermost intercostal muscle.[5]
| Innermost intercostal muscle | |
|---|---|
Innermost intercostal muscle (red), seen from back. | |
| Details | |
| Origin | Infero-posterior border of each rib (above) |
| Insertion | Supero-posterior border of the rib (below) |
| Artery | Intercostal arteries |
| Nerve | Intercostal nerves |
| Actions | Through adduction of upper ribs to the lower ribs the muscles narrow intercostal slits and diminish thorax volume, therefore the muscles represent expiratory muscles. |
| Identifiers | |
| Latin | musculus intercostalis intimus |
| TA98 | A04.4.01.014 |
| TA2 | 2313 |
| FMA | 74086 |
| Anatomical terms of muscle | |
Additional images
Innermost intercostal muscle (shown in red). Animation.
A cutout of the thoracic wall showing the three layers of intercostal muscle - from the left wall.
References
External links
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