Subclavius muscle

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

Structure

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

The fleshy fibers proceed obliquely superolaterally, to be inserted into the groove on the under surface of the clavicle.

Innervation

The nerve to subclavius (or subclavian nerve), which arises from the point of junction of the fifth and sixth cervical nerves, where is called the upper trunk of brachial plexus, innervates the muscle .

Variation

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.

Function

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.

Additional images

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  Subclavius muscle (shown in red). Humerus and scapula are shown in semi-transparent. Animation.

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  Subclavius muscle (shown in red).

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  Anterior surface of sternum and costal cartilages.

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  Left clavicle. Inferior surface.

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  The axillary artery and its branches.

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

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  Subclavius muscle - left view

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  Subclavius muscle- right view

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

External links

• PTCentral
• Pivotal Places: help for problem shoulders