Infraspinatus

Musculus infraspinatus

MuscularDeep musclesThoraxLeft and right

View left in 3D View right in 3D

What it is
Thick triangular rotator-cuff muscle filling most of the infraspinous fossa below the spine of the scapula and converging on the middle facet of the greater tubercle of the humerus.
Function
The main lateral rotator of the arm; stabilises the humeral head in the glenoid.
Size
About 15 cm long and ~10 cm wide at its origin.
Clinical note
Wastes when the suprascapular nerve is trapped at the spinoglenoid notch, a classic overuse injury of volleyball players.

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