Skeletal muscles may move a body part away from the midline. What is this movement called?

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

Answer: (B)

Moving a body part away from the body's midline is abduction. The midline is an imaginary line that runs down the center of the body, dividing it into left and right halves. When a limb moves outward, away from that center line—such as lifting the arm straight out to the side or spreading the fingers—the action is abduction. The opposite is adduction, which brings a part toward the midline, like lowering the arm back to the body. Flexion bending a joint and rotation turning a part around its axis are different movements. So the described movement matches abduction.