Abduction is movement of a limb away from the midline.

• A. Adduction
• B. Flexion
• C. Extension
• D. Abduction

Answer: (D)

Abduction is movement of a limb away from the body's midline. Think of lifting the arms straight out to the side or moving a leg away from the other leg—these are abduction actions. This happens in the frontal plane, increasing the distance between the limb and the midline. The opposite is adduction, which brings a limb toward the midline. Flexion and extension describe changes in joint angle: flexion bends a joint to decrease the angle, while extension straightens a joint to increase the angle back toward neutral. The described movement matches abduction.