Teres major

Musculus teres major

MuscularDeep musclesThoraxLeft and right

View left in 3D View right in 3D

What it is
Thick rounded muscle from the dorsal surface of the inferior angle of the scapula, running up and laterally with latissimus dorsi to the medial lip of the intertubercular groove of the humerus.
Function
Adducts, extends and medially rotates the arm.
Size
About 12 cm long and 3–4 cm wide.
Clinical note
Nicknamed "lat's little helper"; with teres minor and the long head of triceps it bounds the quadrangular and triangular spaces through which axillary vessels and nerves pass.

Nearby muscular structures Caval opening of the diaphragm, Infraspinatus, Pectoralis major, Pectoralis minor, Rhomboid major, Rhomboid minor, Serratus anterior, Subscapularis, Supraspinatus, Teres minor