Internal intercostal muscle
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At the time the article was created Craig Hacking had no recorded disclosures.
View Craig Hacking's current disclosuresAt the time the article was last revised Yvette Mellam had no financial relationships to ineligible companies to disclose.
View Yvette Mellam's current disclosures- Internal intercostal muscles
- Intercostales interni
The internal intercostal muscles are important muscles of respiration. They number eleven on each side and are located in the intercostal spaces, reducing the transverse dimension of the thoracic cavity during expiration.
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Gross anatomy
The internal intercostal muscles are the middle muscle of the three intercostal muscles and arise from the costal groove of the rib above. The fibers run in a downwards, backwards and lateral direction (perpendicular to the external intercostal muscles) and insert into the superior border of the rib below. Anteriorly, the lower muscles become continuous with the internal oblique muscles in the anterolateral abdominal wall. As their name indicates, they are internal to the external intercostal muscles.
Blood supply
arterial supply: anterior and posterior intercostal arteries
venous drainage: internal thoracic vein and intercostal veins
Innervation
Muscular branches from the intercostal nerves of the respective intercostal space (T1-T11), which run with the intercostal vessels under the costal groove in between the internal and innermost intercostal muscles.
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Action
Internal intercostal muscle contraction causes reduction in volume of the thoracic cavity in the transverse dimension, expelling air from the lungs during expiration. They are weaker than the external intercostal muscles.
References
- 1. Last's anatomy, regional and applied. Churchill Livingstone. ISBN:044304662X. Read it at Google Books - Find it at Amazon
- 2. Moore KL. Clinically Oriented Anatomy. Keith L. Moore, Arthur F. Dalley II, Anne M.R. Agur. Lippincott Williams & Wilkins. ISBN:1451184476. Read it at Google Books - Find it at Amazon
- 3. Handbook of Cardiac Anatomy, Physiology, and Devices. Humana Press. ISBN:1603273719. Read it at Google Books - Find it at Amazon
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