Teres Major
Shoulder & Scapula · Upper Limb
Teres Major belongs to the Shoulder & Scapula group of the Upper Limb. Its origin is Posterior surface of inferior angle of scapula, and it inserts onto Medial lip of intertubercular (bicipital) groove of humerus. Its chief action is that it adduction and medial rotation of arm. Its nerve supply is the Lower subscapular nerve (C6, C7).
Origin, Insertion, Action & Nerve
Origin
Posterior surface of inferior angle of scapula
Insertion
Medial lip of intertubercular (bicipital) groove 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 of scapula
Insertion
Medial lip of intertubercular (bicipital) groove 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)
OIANS stands for Origin, Insertion, Action and Nerve, the four facts that uniquely define every skeletal muscle. To learn the Teres Major, work through them in order: picture its origin, trace the muscle to its insertion, reason out the action that shortening between those two points must create, then add the nerve that drives it.
Most students remember the Teres Major fastest by linking its action back to its attachments rather than memorising each fact in isolation. Once the origin and insertion make sense, the action usually follows logically.
Teres Major quick facts
- Region
- Upper Limb
- Group
- Shoulder & Scapula
- Origin
- Posterior surface of inferior angle of scapula
- Insertion
- Medial lip of intertubercular (bicipital) groove of humerus
- Action
- Adduction and medial rotation of arm
- Nerve
- Lower subscapular nerve (C6, C7)
- Spinal roots
- C6, C7
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 of scapula
What is the insertion of the Teres Major?
Medial lip of intertubercular (bicipital) groove 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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