Which muscles are involved in shoulder flexion?

Which muscles are involved in shoulder flexion?

• A. Posterior Deltoid and Latissimus Dorsi
• B. Supraspinatus and Infraspinatus
• C. Anterior Deltoid and Pectoralis Major (Clavicular Head), assisted by Coracobrachialis and Biceps Brachii
• D. Teres Minor and Subscapularis

Answer: (C)

Shoulder flexion means lifting the arm forward, and the muscles that drive this action are those crossing the front of the shoulder. The main players are the anterior portion of the deltoid and the clavicular (upper) part of the pectoralis major. They contract to raise the arm from the side toward the front. The coracobrachialis and the biceps brachii (long head) also cross the shoulder joint and provide additional assistance to flex the arm, especially when the elbow is flexed and the forearm is supinated. The other muscles listed don’t flex the shoulder as their primary role—posterior deltoid and latissimus dorsi/Teres major favor extension or internal rotation and adduction, while supraspinatus mainly initiates abduction and the infraspinatus and teres minor are external rotators. Subscapularis is an internal rotator.

Shoulder flexion means lifting the arm forward, and the muscles that drive this action are those crossing the front of the shoulder. The main players are the anterior portion of the deltoid and the clavicular (upper) part of the pectoralis major. They contract to raise the arm from the side toward the front. The coracobrachialis and the biceps brachii (long head) also cross the shoulder joint and provide additional assistance to flex the arm, especially when the elbow is flexed and the forearm is supinated. The other muscles listed don’t flex the shoulder as their primary role—posterior deltoid and latissimus dorsi/Teres major favor extension or internal rotation and adduction, while supraspinatus mainly initiates abduction and the infraspinatus and teres minor are external rotators. Subscapularis is an internal rotator.