Which action is NOT primarily associated with the latissimus dorsi?

• A. Extension
• B. Abduction
• C. Adduction
• D. Medial rotation

Answer: (B)

The latissimus dorsi is a large pulling muscle of the back that mainly powers movements bringing the arm backward, toward the body, and rotating it inward. Its primary shoulder actions are extension (pulling the arm back from a flexed position), adduction (bringing the arm toward the midline), and medial (internal) rotation. It also assists in movements like climbing, where the arm is pulled downward and inward. Abduction, which is lifting the arm away from the body, is not a primary action of this muscle; that movement is mainly handled by the deltoid (with support from the supraspinatus early on). So the action that is not primarily associated with the latissimus dorsi is abduction.