Origin: Supruaspinous fossa of the scapula Insertion: Superior aspect of the greater tubercle of the humerus

Action: Synergist with deltoid in arm abduction at the shoulder; Stabilizes shoulder by drawing in the humerus towards the glenoid fossa of the scapula (gelnoid fossa: concavity in the head of scapula that receives the head of humerus to form the shoulder joint)