Subclavius muscle

Subclavius muscle
Deep muscles of the chest and front of the arm, with the boundaries of the axilla. (Subclavius visible at upper left, above first rib.)
Latin musculus subclavius
Gray's subject #122 438
Origin first rib
Insertion    subclavian groove of clavicle
Artery thoracoacromial trunk, clavicular branch
Nerve nerve to subclavius
Actions depression of clavicle

The Subclavius is a small triangular muscle, placed between the clavicle and the first rib.[1] Along with the pectoralis major and pectoralis minor muscles, the subclavius muscle makes up the anterior wall of the axilla.[2]

Contents

Origin and insertion

It arises by a short, thick tendon from the first rib and its cartilage at their junction, in front of the costoclavicular ligament.[1]

The fleshy fibers proceed obliquely superolaterally, to be inserted into the groove on the under surface of the clavicle between the costoclavicular and conoid ligaments.[1]

Action

The Subclavius depresses the shoulder, carrying it downward and forward. It draws the clavicle inferiorly as well as anteriorly.

The Subclavius protects the underlying brachial plexus and subclavian vessels from a broken clavicle - the most frequently broken long bone.

Variations

Insertion into coracoid process instead of clavicle or into both clavicle and coracoid process. Sternoscapular fasciculus to the upper border of scapula. Sternoclavicularis from manubrium to clavicle between Pectoralis major and coracoclavicular fascia. [1]

Additional images

References

  1. ^ a b c d "IV. Myology: 13". Gray's Anatomy: The Muscles Connecting the Upper Extremity to the Anterior and Lateral Thoracic Walls. 1918. http://education.yahoo.com/reference/gray/subjects/subject/122#p438. 
  2. ^ Drake, Richard, et al. Gray's Anatomy For Students, Elsevier Inc., 2005

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 As such, some of the information contained within it may be outdated.

External links