The infraspinatus and teres minor rotate the head of the humerus outward (external, or lateral, rotation); they also assist in carrying the arm backward (extension of the glenohumeral joint).
It innervates the supraspinatus and infraspinatus muscles.
Other transverse extensors, the infraspinatus and teres minor, also work in tandem with the posterior deltoid as external (lateral) rotators, antagonists to strong internal rotators like the pecs and lats.
It unveils clearly the whole area from the subedge of the subscapularis tendon until the intersection between infraspinatus tendon and musculus teres minor.
If the lifter does not lock the elbow, the lateral rotators (posterior deltoid, infraspinatus, teres minor) are also involved in preventing internal (medial) rotation.
The infraspinatus and teres minor insert on the greater tubercle, and work to laterally, or externally, rotate the humerus.
The four muscles of supraspinatus, infraspinatus, teres minor and subscapularis form a musculo-ligamentous girdle called the rotator cuff.
However, a correlation between full-thickness rotator cuff tear size and the pennation angle of the supraspnatus and infraspinatus muscles was evident.
