Which muscles act as prime movers for scapular adduction and downward rotation?

Which muscles act as prime movers for scapular adduction and downward rotation?

• A. Upper trapezius
• B. Serratus anterior
• C. Lower trapezius
• D. Rhomboids

Answer: (D)

Adduction (retraction) of the scapula combined with downward rotation is produced most effectively by the rhomboids. The rhomboid major and rhomboid minor attach along the medial border of the scapula and pull it toward the spine, which creates retraction. At the same time, their pull on the scapula also rotates it downward, aligning the glenoid cavity for certain arm movements and providing stable control during pulling or rowing actions. Other muscles here don’t match this combined action as the prime movers: the upper trapezius mainly elevates and helps upward rotation; serratus anterior protracts the scapula and upwardly rotates it; the lower trapezius depresses and upwardly rotates. So the rhomboids are the best fit for scapular adduction with downward rotation.

Adduction (retraction) of the scapula combined with downward rotation is produced most effectively by the rhomboids. The rhomboid major and rhomboid minor attach along the medial border of the scapula and pull it toward the spine, which creates retraction. At the same time, their pull on the scapula also rotates it downward, aligning the glenoid cavity for certain arm movements and providing stable control during pulling or rowing actions.

Other muscles here don’t match this combined action as the prime movers: the upper trapezius mainly elevates and helps upward rotation; serratus anterior protracts the scapula and upwardly rotates it; the lower trapezius depresses and upwardly rotates. So the rhomboids are the best fit for scapular adduction with downward rotation.