Teres major muscle

Teres major muscle
Muscles on the dorsum of the scapula, and the Triceps brachii muscle: #3 latissimus dorsi muscle #5 teres major muscle #6 teres minor muscle #7 supraspinatus muscle #8 infraspinatus muscle #13 long head of triceps brachii muscle
Surface anatomy of the back. (Label for Teres major at upper right.)
Latin	musculus teres major
Gray's	subject #123 442
Origin	posterior aspect of the inferior angle of the scapula
Insertion	medial lip of the intertubercular sulcus of the humerus
Artery	Subscapular and circumflex scapular arteries
Nerve	Lower subscapular nerve (segmental levels C6 and C7)
Actions	Internal rotation (medial rotation) of the humerus

The teres major muscle is a muscle of the upper limb and one of six scapulohumeral muscles. It is a thick but somewhat flattened muscle, innervated by the lower subscapular nerve (c5,c6).

Origin and insertion

It arises from the oval area on the dorsal surface of the inferior angle of the scapula, and from the fibrous septa interposed between this muscle and the rotator cuff lateral rotator pair of the teres minor and infraspinatus.

The fibers of teres major insert into the medial lip of the bicipital groove of the humerus.

Relations

Posterior view showing the relations between teres major muscle (in red) and the other muscles connecting the upper extremity to the vertebral column.

The tendon, at its insertion, lies behind that of the latissimus dorsi, from which it is separated by a bursa, the two tendons being, however, united along their lower borders for a short distance.

Together with teres minor muscle, teres major muscle forms the axillary space, through which several important arteries and veins pass. Teres major is not part of the rotator cuff of the shoulder, but it does combine with the deltoideus to make the six scapulohumeral muscles.

The teres major muscle is innervated by the lower subscapular nerve of the brachial plexus.

Action

The teres major is a medial rotator and adductor of the humerus and assists the latissimus dorsi in drawing the previously raised humerus downward and backward (extension, but not hyper extension). It also helps stabilize the humeral head in the glenoid cavity.

Additional images

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  Deep muscles of the chest and front of the arm, with the boundaries of the axilla.

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  Left humerus. Anterior view.

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  Teres major muscle

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  Left scapula. Posterior surface.

See also

• Accessory muscles of the scapula

External links

• 711655502 at GPnotebook
• SUNY Figs 03:03-06
• PTCentral

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.