State the origins of the clavicular and sternocostal heads of the pectoralis major, its insertion, and its primary actions.

• A. Origins: clavicular head from the medial half of the clavicle; sternocostal head from the sternum and upper costal cartilages. Insertion: crest of the greater tubercle of the humerus. Actions: flexion (clavicular head), adduction, and internal rotation of the humerus.
• B. Origins: clavicular head from the medial clavicle; sternocostal head from the vertebral border of the scapula. Insertion: lesser tubercle. Actions: lateral rotation.
• C. Origins: from the scapula; Insertion: intertubercular groove; Actions: protraction.
• D. Origins: from the clavicle; Insertion: olecranon; Actions: extension.

Answer: (A)