Which muscles are prime movers for scapular adduction?

Which muscles are prime movers for scapular adduction?

• A. Serratus anterior
• B. Rhomboids
• C. Pectoralis minor
• D. Latissimus dorsi

Answer: (B)

Focusing on scapular adduction means identifying the muscles that pull the shoulder blades toward the spine. The rhomboids (major and minor) are the primary movers here because they attach from the spine to the medial border of the scapula and contract to bring the scapulae together, i.e., retract them. They also help downwardly rotate the scapula and stabilize the scapulothoracic joint. Serratus anterior, by contrast, pulls the scapula forward and around the rib cage (protraction), so it doesn’t produce adduction. Pectoralis minor attaches under the shoulder and tends to protract and depress the scapula. Latissimus dorsi acts mainly on the humerus (extension, adduction, internal rotation) and has less direct effect on scapular retraction. So, the rhomboids are the best fit for scapular adduction.

Focusing on scapular adduction means identifying the muscles that pull the shoulder blades toward the spine. The rhomboids (major and minor) are the primary movers here because they attach from the spine to the medial border of the scapula and contract to bring the scapulae together, i.e., retract them. They also help downwardly rotate the scapula and stabilize the scapulothoracic joint.

Serratus anterior, by contrast, pulls the scapula forward and around the rib cage (protraction), so it doesn’t produce adduction. Pectoralis minor attaches under the shoulder and tends to protract and depress the scapula. Latissimus dorsi acts mainly on the humerus (extension, adduction, internal rotation) and has less direct effect on scapular retraction. So, the rhomboids are the best fit for scapular adduction.