The Infraspinatus muscle is one of the four rotator cuff muscles crossing the shoulder joint and is commonly injured. It is the main external rotator of the shoulder joint.
Origin - Posterior surface of the scapula (below the spine of the scapula).
Insertion - Greater tuberosity on the humerus.
Actions - Shoulder horizontal abduction.
External rotation. Shoulder extension
Innervation - Suprascapular nerve.
Daily uses - Brushing hair.
Example strengthening exercises - Lateral raise.
Shoulder external (lateral) rotation.
Example stretches - Internal rotation stretch.
Posterior shoulder stretch.