Muscles that Horizontally Abduct the Shoulder

Main Mover at Shoulder:

• Posterior Deltoid

Main Movers at Scapula:

• Middle Trapezius

• Lower Trapezius

• Rhomboid Major

• Rhomboid Minor

Supporting Cast at Scapula + Shoulder:

• Infraspinatus

• Teres Minor

• Middle Deltoid (to hold arm up)

• Supraspinatus (to hold arm up)

• Upper Trapezius (to hold scapula up)