Teres major

Beside the cuff, not part of it

Teres major is a distinct muscle, not a head of teres minor and not a member of the rotator cuff.

Both teres muscles can now be selected in this scene. Start with the full name in the structure list, then restore the bones before comparing their courses. An isolated silhouette alone is a poor guide to anatomical position.

Sources: Arm anatomy tables

Inferior scapula to the medial lip of the groove

Teres major begins on the posterior inferior-angle region of the scapula. It ends at the medial lip of the humeral intertubercular groove, also described as the crest of the lesser tubercle.

This is different from the greater-tubercle attachment of teres minor. The names “lesser tubercle” and “crest of the lesser tubercle” should not be treated as identical attachment footprints.

The bone meshes provide regional context, not separate clickable footprints. The source does not resolve all tendon layers or show a continuous fiber-by-fiber connection to bone.

Sources: Loyola anatomy · Arm anatomy tables

Internal rotation, adduction and assistance in extension

Teres major turns the arm medially and draws it toward the body; it also assists shoulder extension. Teres minor instead contributes to lateral rotation.

The source pose is fixed. Turning the camera does not raise the arm or rotate the humerus within the socket; the viewer does not simulate muscle contraction or shoulder mechanics.

Compare the two surfaces to orient your study, not to estimate strength. “Major” does not mean that a zoomed rendering can establish a muscle’s force or importance in a particular activity.

Sources: Loyola anatomy · Arm anatomy tables

Lower subscapular nerve

The lower subscapular nerve supplies teres major. Teres minor has a different named supply: the axillary nerve.

Nerves and vessels are not loaded in this subset, so the text describes connections you cannot select in the viewer.

Selection color is not a map of innervation, vascular territory or muscle activation.

Sources: Loyola anatomy · Arm anatomy tables

Read the model

Explore teres major in 3D

1. Orient the isolated muscle. Choose Back or Oblique, then Focus selection if needed. Rotate the camera to inspect the whole surface without changing the source pose.
2. Restore both bones. Choose Show context and Fade others. Alternate Teres major, Scapula and Humerus in the structure list to follow the relative position of each mesh.
3. Compare the other teres muscle. Select Teres minor, then open its title for the matching guide. Use the reciprocal related link to return; both pages use the same shoulder-and-arm subset.
4. Review the key differences. Open the paired reading block for a compact comparison of attachment, rotation, nerve and cuff membership. Compare teres minor and major →

Sources and editorial status

This guide uses independently written explanations with links to the evidence behind them. Source checking and specialist anatomical review are separate steps; the latter is still pending.

1. Loyola University Chicago — LUMEN, Teres major

   Scapular origin, humeral attachment, principal actions and lower subscapular nerve. No source illustrations reproduced.

2. Texas Tech University Health Sciences Center El Paso — Axilla, Posterior Shoulder, & Arm

   Teres major and minor rows: attachments, actions, nerve supply and distinction from the four rotator-cuff muscles. No source images reproduced.

3D geometry and its separate license are credited beneath the viewer. References do not imply endorsement of this site.