Which muscles are the agonists for upward rotation of the scapula?

• A. Trapezius (Upper and Lower), Serratus Anterior
• B. Levator Scapulae, Rhomboids
• C. Pectoralis Minor, Serratus Anterior
• D. Trapezius (Lower), Latissimus Dorsi

Answer: (A)

Upward rotation of the scapula during arm elevation is produced by a coordinated action of the trapezius and serratus anterior. The upper trapezius helps lift and rotate the scapula, while the lower trapezius pulls the inferior angle of the scapula downward and toward the spine, which completes the upward rotation. Serratus anterior anchors the scapula to the rib cage and, when the arm lifts, protracts and rotates the scapula so the glenoid fossa tilts upward, allowing full shoulder elevation.

The other muscles listed don’t promote upward rotation as their primary action: levator scapulae and rhomboids tend to elevate and downwardly rotate the scapula; pectoralis minor pulls the scapula anteriorly and downward, contributing to downward rotation; latissimus dorsi depresses and downwardly rotates the scapula.