Pectoralis minor
Pectoralis minor | |
---|---|
thoracoacromial trunk | |
Nerve | Medial pectoral nerve (C8) |
Actions | Stabilizes the scapula by drawing it inferiorly and anteriorly against the thoracic wall, raises ribs in inhalation |
Identifiers | |
Latin | musculus pectoralis minor |
TA98 | A04.4.01.006 |
TA2 | 2305 |
FMA | 13109 |
Anatomical terms of muscle] |
Pectoralis minor muscle (
Structure
Attachments
From the muscle's origin, the muscle's fibers pass superiorly and laterally, converging to form a flat tendon.
Origin
Pectoralis minor muscle arises from the upper margins and outer surfaces of the 3rd, 4th, and 5th
Insertion
Its tendon inserts onto the medial border and upper surface of the coracoid process of the scapula.[1][2]
Innervation
The muscle receives motor innervation from the medial pectoral nerve.[3]
Relations
Pectoralis minor muscle forms part of the anterior wall of the axilla.[4] It is covered anteriorly (superficially) by the clavipectoral fascia. The medial pectoral nerve pierces the pectoralis minor and the clavipectoral fascia. In attaching to the coracoid process, the pectoralis minor forms a 'bridge' - structures passing into the upper limb from the thorax will pass directly underneath.[5]
Axillary nodes are classified according to their positions relative to the pectoralis minor muscle. Level 1 are lateral, Level 2 are deep, Level 3 are medial. The pectoralis minor divides the axillary artery into three parts (in contrary sequence compared to the nodes) - first part medial, second part deep/posterior, third part lateral in relation to the pectoralis minor.
Variations
The origin is from the second, third and fourth or fifth ribs. The tendon of insertion may extend over the coracoid process to the greater tubercle. It may be split into several parts. Absence of this muscle is rare but happens with certain uncommon diseases, such as the Poland syndrome.[citation needed]
Function
Pectoralis minor muscle
See also
References
This article incorporates text in the public domain from page 438 of the 20th edition of Gray's Anatomy (1918)
- ^ ISBN 978-0-7020-3528-9.
- ISBN 978-0-12-410390-0.
- PMID 32310519, retrieved 2023-01-13
- ISBN 978-0-443-10373-5.
- ^ http://www.teachmeanatomy.com/muscles-of-the-pectoral-region/ [permanent dead link]
External links
- Illustration: upper-body/pectoralis-minor from The Department of Radiology at the University of Washington
- Anatomy figure: 04:04-05 at Human Anatomy Online, SUNY Downstate Medical Center
- Anatomy figure: 05:02-08 at Human Anatomy Online, SUNY Downstate Medical Center
- Anatomy photo:05:ov-0200 at the SUNY Downstate Medical Center
- Anatomy photo:05:01-0102 at the SUNY Downstate Medical Center
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