Rotator Cuff muscles = Supraspinatus, Infraspinatus, Subscapularis, and Teres Minor.
Supraspinatus - Initiates abduction at shoulder, and is a lateral rotator of the humerus.
Infraspinatus - Also a lateral rotator of the humerus.
Subscapularis - Medially rotates and adducts the humerus at shoulder.
Teres Minor - Rotates the humerus laterally and weakly adducts at shoulder.
The tendons blend with the joint capsule and form a musculotendinous collar that surrounds the poster, superior, and anterior aspects of the glenohumeral joint. They draw the humeral head toward the glenoid fossa, strengthening the glenohumeral joint.
I don't bother training them, but its gonna be in my exam tomorrow.