Subclavius muscle

Article in other languages:

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 artery, 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]

1 Origin and insertion
2 Action
3 Variations
4 Additional images
5 References
6 External links

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 lateralward and generally upward, 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

Anterior surface of sternum and costal cartilages.

Left clavicle. Inferior surface.

The axillary artery and its branches.

The right brachial plexus (infraclavicular portion) in the axillary fossa; viewed from below and in front.

References

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 As such, some of the information contained within it may be outdated.