Major Muscles that Act on the Shoulder Joint (Humerus)

Question 1

Muscle: Pectoralis major

Answer 1

Primary Function(s):
Adducts, horizontally adducts, extends, flexes and medially rotates the shoulder (humerus)

Resistance Exercise(s)
Push-ups, bench press, chest flys

Question 2

Muscle: Deltoid

Answer 2

Primary Function(s):
Anterior: flexes, horizontally adducts and internally rotates the shoulder (humerus)
Middle: abducts the shoulder (humerus)
Posterior: extends, externally rotates and horizontally abducts the shoulder (humerus)

Resistance Exercise(s):
Anterior: front dumbbell raises
Middle: side dumbbell raises
Posterior: reverse flys
All: overhead

Question 3

Muscle: Latissimus dorsi

Answer 3

Primary Function(s):
Extends, adducts, horizontally abducts and internally rotates the shoulder (humerus)

Resistance Exercise(s):
Chin-ups, lat pulldowns, seated rows, bent-over rows, rope climbing

Question 4

Rotator cuff – S.I.T.S.
Supraspinatus
Infraspinatus
Teres minor
Subscapularis

Answer 4

Primary Function(s):
All contribute to the stabilization of the humerus
Supraspinatus: abducts the shoulder (humerus)
Infraspinatus and teres minor: externally rotate the shoulder (humerus)
Subscapularis: internally rotates the shoulder (humerus)

Resistance Exercise(s):
Supraspinatus: side dumbbell raises
Infraspinatus and teres minor: external rotation with tubing
Subscapularis: internal rotation with tubing

Question 5

Muscle: Teres major

Answer 5

Primary Function(s):
Extends, adducts and internally rotates the shoulder (humerus)

Resistance Exercise(s):
Chin-ups, lat pulldowns, seated rows, bent-over rows, rope climbing