Teres Major
Shoulder & Scapula · Upper Limb
The teres major is a thick, rounded muscle running along the lower lateral border of the scapula. It arises from the posterior surface of the inferior angle and lateral border of the scapula and travels to the medial lip of the intertubercular (bicipital) groove of the humerus. Acting on the shoulder, it adducts the arm and rotates it medially, working closely with latissimus dorsi to pull the raised arm downward and backward. It is supplied by the lower subscapular nerve (C6, C7). Although its name links it to the rotator cuff by position, teres major is not one of the four cuff muscles because it does not attach to the joint capsule.
Origin, Insertion, Action & Nerve
Origin
Posterior surface of inferior angle and lateral border of scapula
Insertion
Medial lip of intertubercular (bicipital) groove of humerus or crest of lesser tubercle of humerus
Action
Adduction and medial rotation of arm
Nerve
Lower subscapular nerve (C6, C7)
Attachments explained
The Teres Major is defined first by where it attaches. Its origin is the more fixed anchor, usually the proximal or more stable end that stays put during contraction, while its insertion is the more mobile point that is pulled toward the origin when the muscle shortens.
Origin
Posterior surface of inferior angle and lateral border of scapula
Insertion
Medial lip of intertubercular (bicipital) groove of humerus or crest of lesser tubercle of humerus
Action & function
When the Teres Major contracts, it produces the following movement: Adduction and medial rotation of arm.
As part of the Shoulder & Scapula group of the Upper Limb, it works alongside neighbouring muscles to generate smooth, coordinated movement and to stabilise the structures it acts on.
Nerve supply & clinical relevance
The Teres Major receives its nerve supply from the Lower subscapular nerve (C6, C7). This nerve carries fibres from spinal segment(s) C6, C7.
Because a muscle can only contract when its nerve is intact, injury to the Lower subscapular nerve or to its spinal roots (C6, C7) can weaken or paralyse the Teres Major, impairing the movements it normally produces (adduction and medial rotation of arm). This is why knowing the innervation is central to localising nerve lesions in clinical practice.
How to study the Teres Major (the OIANS method)
Study teres major as the working partner of latissimus dorsi. Both pull the raised arm down and back, adducting and medially rotating it, so learning their shared action once covers both muscles. Its origin near the inferior angle of the scapula and its insertion on the medial lip of the bicipital groove explain why it swings the arm toward the body.
Guard against a common trap: teres major looks like a cuff muscle but is not one, because it does not blend with the joint capsule. Remember it is supplied by the lower subscapular nerve, and use the medial-lip attachment to distinguish it from teres minor, which inserts on the greater tubercle instead.
Frequently asked questions
Where is the Teres Major located?
The Teres Major is a muscle of the Shoulder & Scapula group, located in the Upper Limb.
What is the origin of the Teres Major?
Posterior surface of inferior angle and lateral border of scapula
What is the insertion of the Teres Major?
Medial lip of intertubercular (bicipital) groove of humerus or crest of lesser tubercle of humerus
What movements does the Teres Major produce?
Adduction and medial rotation of arm
What nerve supplies the Teres Major?
Lower subscapular nerve (C6, C7)
Is the Teres Major free to study in OIANS?
Yes. The Teres Major is free in OIANS: its full origin, insertion, action and nerve details are open to everyone in the Muscle Directory, and because it belongs to the Upper Limb it is also covered by the free Quiz and Flashcard decks. The other regions, the "All Muscles" deck, and the Progress and Explore tools are unlocked with a one-time Lifetime purchase.
Related muscles
Study the Teres Major
Test yourself on Upper Limb muscles with interactive quizzes and flashcards in the free OIANS app.
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