What is the primary action of the serratus anterior?

What is the primary action of the serratus anterior?

• A. Protracts the scapula and prevents winging
• B. Retracts the scapula
• C. Elevates the scapula
• D. Depresses the scapula

Answer: (A)

The serratus anterior primarily protracts the scapula, pulling it forward along the rib cage, and anchors it to the thoracic wall so the medial border stays flat against the ribs, which prevents winging. It also assists with upward rotation of the scapula during arm elevation. Other motions like retracting, elevating, or depressing the scapula are performed mainly by other muscles (rhomboids and middle trapezius for retraction; upper trapezius and levator scapulae for elevation; lower trapezius and pectoralis minor for depression), not by the serratus anterior.

The serratus anterior primarily protracts the scapula, pulling it forward along the rib cage, and anchors it to the thoracic wall so the medial border stays flat against the ribs, which prevents winging. It also assists with upward rotation of the scapula during arm elevation. Other motions like retracting, elevating, or depressing the scapula are performed mainly by other muscles (rhomboids and middle trapezius for retraction; upper trapezius and levator scapulae for elevation; lower trapezius and pectoralis minor for depression), not by the serratus anterior.