Pectoralis minor muscle
Pectoralis minor (shown in red).
Pectoralis minor muscle (shown in red). The bone shown in blue is shoulder blade.
|Latin||Musculus pectoralis minor|
|Origin||Third to fifth ribs, near their costal cartilages|
|Insertion||Medial border and superior surface of the coracoid process of the scapula|
|Pectoral branch of the thoracoacromial trunk|
|Medial pectoral nerve (C8, T1)|
|Actions||Stabilizes the scapula by drawing it inferiorly and anteriorly against the thoracic wall, raises ribs in inspiration|
|Anatomical terms of muscle|
The pectoralis minor muscle is covered anteriorly (superficially) by the clavipectoral fascia. The Lateral 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.
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.
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.
|Wikimedia Commons has media related to Pectoralis minor muscles.|
- Illustration: upper-body/pectoralis-minor from The Department of Radiology at the University of Washington
- 13631566 at GPnotebook
- 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
- Muscles/PectoralisMinor at exrx.net