Teres Major Muscle Anatomy

Overview
Origin Inferior angle of the medial border of the scapula
Insertion Medial crest of the intertubercular groove (bicipital groove)
Action Shoulder internal rotation
Shoulder extension
Shoulder adduction
Nerve Lower subscapular nerve (C5, C6, C7)
Artery Circumflex scapular artery or the thoracodorsal artery

Location & Overview

There teres major muscle is a small muscle of the upper back, which attaches to the humerus and the scapula. It is a thick muscle which is somewhat flat in shape. It is one of seven scapulohumeral muscles. The scapulohumeral muscles are: the deltoid, coracobrachialis, infraspinatus, subscapularis, supraspinatus, teres minor and the teres major. It has somewhat of a synergistic action with the latissimus dorsi so is occasionally referred to as the ‘lat’s little helper’ [1] [2].

teres major muscle from a posterior view

Here we can see an image of the teres major muscle from a posterior view.

Origin & Insertion

The teres major originates at the inferior angle of the medial border of the scapula and inserts at the medial crest of the intertubercular groove (also known as the bicipital groove). The bicipital groove is where the long head tendon of the biceps brachii is located [3] [4].

teres major origin

The teres major originates from the posterior side of the scapula. Specifically, the inferior aspect of the medial border of the scapula.

teres major insertion

The teres major inserts on the medial crest of the intertubercular groove. Also known as the bicipital groove.

Actions

The teres major can perform internal rotation of the humerus, shoulder extension and shoulder adduction [5] [6].

Innervation

The teres major is innervated by the lower subscapular nerve (C5, C6, C7) [7].

Blood Supply

The teres major muscle gets its blood supply from one of the branches of the subscapular artery, either the circumflex scapular artery or the thoracodorsal artery [8] [9].

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Teres Major Flashcards

References

References
1 Moore KL, Agur AMR, Dalley AF. Clinically Oriented Anatomy. 8th ed. Philadelphia: Lippincot Williams & Wilkins; 2017.
2, 4, 6, 8 Wu JG, Bordoni B. Anatomy, Shoulder and Upper Limb, Scapulohumeral Muscle. [Updated 2021 Sep 24]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK546633/
3, 5 Donohue BF, Lubitz MG, Kremchek TE. Sports Injuries to the Latissimus Dorsi and Teres Major. Am J Sports Med. 2017 Aug;45(10):2428-2435. doi: 10.1177/0363546516676062. Epub 2016 Dec 20. PMID: 28125914.
7, 9 Dancker M, Lambert S, Brenner E. The neurovascular anatomy of the teres major muscle. J Shoulder Elbow Surg. 2015 Mar;24(3):e57-67. doi: 10.1016/j.jse.2014.07.001. Epub 2014 Sep 17. PMID: 25240812.