A- All fibers:Abduct the shoulder (glenohumeral joint)Anterior fibers:Flex the shoulder (G/H joint)Medially rotate the shoulder (G/H joint)Horizontally adduct the shoulder (G/H joint)Posterior fibers:Extend the shoulder (G/H joint)Laterally rotate the shoulder (G/H joint)Horizontally abduct the shoulder (G/H joint)O- Lateral one-third of clavicle, acromion, and spine of scapulaI- Deltoid tuberosity To palpate flex elbow and have the patient abduct the shoulder against resistance. deltoid