Which action is shared by both pectoralis major and pectoralis minor?

Which action is shared by both pectoralis major and pectoralis minor?

• A. Flexes the elbow
• B. Abducts the arm at the shoulder
• C. Draws scapula anteriorly and inferiorly
• D. Rotates the humerus medially

Answer: (C)

Focusing on how the shoulder girdle moves, both pectoral muscles can influence the position of the scapula against the thorax. The shared action is drawing the scapula anteriorly (protraction) and downward (depression). Pectoralis minor attaches to ribs 3–5 and the coracoid process, and its direct job is to protract and depress the scapula. Pectoralis major, while mainly moving the humerus, can contribute to scapular depression and a forward (anterior) tilt when the arm is fixed or during pushing actions, helping bring the shoulder girdle toward the chest. The other options don’t represent a motion these two muscles share: elbow flexion is performed by forearm muscles, not these chest muscles; abduction at the shoulder is mainly by deltoid and supraspinatus; medial rotation of the humerus is a primary action of pectoralis major but not of pectoralis minor.

Focusing on how the shoulder girdle moves, both pectoral muscles can influence the position of the scapula against the thorax. The shared action is drawing the scapula anteriorly (protraction) and downward (depression). Pectoralis minor attaches to ribs 3–5 and the coracoid process, and its direct job is to protract and depress the scapula. Pectoralis major, while mainly moving the humerus, can contribute to scapular depression and a forward (anterior) tilt when the arm is fixed or during pushing actions, helping bring the shoulder girdle toward the chest. The other options don’t represent a motion these two muscles share: elbow flexion is performed by forearm muscles, not these chest muscles; abduction at the shoulder is mainly by deltoid and supraspinatus; medial rotation of the humerus is a primary action of pectoralis major but not of pectoralis minor.