| Pectoralis minor | |
|---|---|
| Latin | musculus pectoralis minor |
| Gray's | subject #122 438 |
| Origin | third to fifth ribs, near their costal cartilages |
| Insertion | medial border and superior surface of the coracoid process of the scapula |
| Artery | pectoral branch of the thoracoacromial trunk |
| Nerve | medial pectoral nerve (C8, T1) |
| Actions | stabilizes the scapula by drawing it inferiorly and anteriorly against the thoracic wall |
The pectoralis minor is a thin, triangular muscle, situated at the upper part of the chest, beneath the pectoralis major.
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It arises from the upper margins and outer surfaces of the third, fourth, and fifth ribs, near their cartilages and from the aponeuroses covering the intercostalis.
The fibers pass superior and lateral and converge to form a flat tendon, which is inserted into the medial border and upper surface of the coracoid process of the scapula.
The Pectoralis muscle is innervated by the medial pectoral nerve.
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 muscle is covered anteriorly (superficially) by the clavipectoral fascia. The medial pectoral nerve pierces the pectoralis minor and the clavipectoral fascia.
The pectoralis minor depresses the point of the shoulder, drawing the scapula inferior and medial, towards the thorax, and throwing its inferior angle posteriorly.
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.
This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.
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