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The innermost intercostal muscle is a layer of intercostal muscles deep to the plane that contains the intercostal nerves and intercostal vessels and the internal intercostal muscles.

Innermost intercostal muscle
Innermost intercostal muscles back.png
Innermost intercostal muscle (red), seen from back.
OriginInfero-posterior border of each rib (above)
InsertionSupero-posterior border of the rib (below)
Arteryintercostal arteries
Nerveintercostal nerves
ActionsThrough adduction of upper ribs to the lower ribs the muscles narrow intercostal slits and diminish thorax volume, therefore the muscles represent expiratory muscles.
Latinmusculus intercostalis intimus
Anatomical terms of muscle

Additional imagesEdit

External linksEdit

  • Anatomy photo:18:04-0103 at the SUNY Downstate Medical Center - "Thoracic Wall: The Intercostal Nerve and Vessels"
  • Anatomy figure: 18:03-04 at Human Anatomy Online, SUNY Downstate Medical Center - "Transverse section of thorax."
  • thoraxmuscles at The Anatomy Lesson by Wesley Norman (Georgetown University)