Pectoralis minor muscle

Pectoralis minor
Pectoralis minor (shown in red).
Pectoralis minor muscle (shown in red). The bone shown in blue is shoulder blade.
Details
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, raises ribs in inspiration
Identifiers
Latin	Musculus pectoralis minor
Dorlands /Elsevier	m_22/12550138
TA	A04.4.01.006
FMA	13109
Anatomical terms of muscle []

The pectoralis minor (/ˌpɛktəˈreɪlᵻs ˈmaɪnər/) is a thin, triangular muscle, situated at the upper part of the chest, beneath the pectoralis major in the human body.

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 minor muscle 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.

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.