Innermost intercostal muscle

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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 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


  1. ^ Rahangdale, Rohit; Tureanu, Luminita; Benzon, Honorio T. (2018-01-01), Benzon, Honorio T.; Raja, Srinivasa N.; Liu, Spencer S.; Fishman, Scott M. (eds.), "Chapter 83 - Truncal Blocks: Paravertebral, Intercostal, Pectoral Nerve, Suprascapular, Ilioinguinal, Iliohypogastric Nerve, and Transversus Abdominis Plane Blocks", Essentials of Pain Medicine (Fourth Edition), Elsevier, pp. 779–788.e2, doi:10.1016/b978-0-323-40196-8.00083-8, ISBN 978-0-323-40196-8, retrieved 2020-11-23
  2. ^ a b Bland, Kirby I.; Copeland, Edward M.; Klimberg, V. Suzanne (2018-01-01), Bland, Kirby I.; Copeland, Edward M.; Klimberg, V. Suzanne; Gradishar, William J. (eds.), "2 - Anatomy of the Breast, Axilla, Chest Wall, and Related Metastatic Sites", The Breast (Fifth Edition), Elsevier, pp. 20–36.e2, doi:10.1016/b978-0-323-35955-9.00002-7, ISBN 978-0-323-35955-9, retrieved 2020-11-23
  3. ^ a b c Rakovich, George; Fréchette, Éric; Deslauriers, Jean (2010-01-01), Lewis, Michael I.; McKenna, Robert J.; Falk, Jeremy A.; Chaux, George E. (eds.), "8 - Thoracic Surgical Anatomy and Procedures", Medical Management of the Thoracic Surgery Patient, Philadelphia: W.B. Saunders, pp. 95–105, doi:10.1016/b978-1-4160-3993-8.00008-8, ISBN 978-1-4160-3993-8, retrieved 2020-11-23
  4. ^ Jacob, S. (2008-01-01), Jacob, S. (ed.), "Chapter 3 - Thorax", Human Anatomy, Churchill Livingstone, pp. 51–70, ISBN 978-0-443-10373-5, retrieved 2020-11-23
  5. ^ Carreiro, Jane E (2009-01-01), Carreiro, Jane E (ed.), "Chapter 5 - The respiratory system", An Osteopathic Approach to Children (Second Edition), Edinburgh: Churchill Livingstone, pp. 85–100, doi:10.1016/b978-0-443-06738-9.00005-8, ISBN 978-0-443-06738-9, retrieved 2020-11-23

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)