Infraspinatus & Teres Minor (Both are rotator cuff muscles located below the spine of the scapula).

Infraspinatus

Origin = Infraspinous fossa.

Insertion = Greater tuberosity of the humerus and its adjacent shaft

Action = GH joint outward rotation and horizontal abduction.

Teres Minor

Origin = Axillary border of the scapula

Insertion = Greater tuberosity of the humerus and its adjacent shaft

Action = GH joint outward rotation and horizontal abduction.

Note: Both muscles participate in abduction and flexion as they pull down on the greater tuberosity as the deltoid pulls upwardly on the middle of the shaft of the humerus.