Teres Major
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The "lat's little helper" — a scapula-to-humerus synergist that extends, adducts, and internally rotates the shoulder alongside the latissimus dorsi.
Detail
Teres major runs from the inferior angle of the scapula to the medial lip of the bicipital groove of the humerus — essentially the same insertion region as the latissimus dorsi, which is why the two act together on nearly every pulling movement (rows, pull-ups, pulldowns). Despite sitting directly beside teres minor, teres major is NOT part of the rotator cuff (SITS) group: it produces internal rotation, the opposite of teres minor's external rotation, and its primary job is bulk shoulder extension/adduction rather than fine joint stabilization.
Key facts
- Origin: inferior angle of the scapula. Insertion: medial lip of the bicipital groove (same region as latissimus dorsi).
- Functions: shoulder extension, adduction, and internal rotation — always as a lat synergist, not a prime mover on its own.
- Not a rotator cuff muscle, despite the name similarity to teres minor and shared location.
- Heavily active in vertical and horizontal pulling (pull-ups, rows, pulldowns).
Connections
- Latissimus Dorsi — shares the same insertion and action; teres major is its constant synergist.
- Extension / Adduction / Internal Rotation — the three actions it produces at the shoulder.
- Rotator Cuff (SITS) — the SITS group it is often confused with but does not belong to.
Sources
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Educational content only — not medical advice. Always consult a qualified professional for individualized guidance, especially around injury, pregnancy, or medical conditions.