Movement away from the midline?

• A. Abduction
• B. Acoustic
• C. Adduction
• D. Achromatism

Answer: (A)

Movement away from the midline is called abduction. In anatomy, abduction describes pulling a limb or structure laterally away from the body's midline—for example, lifting the arm out to the side or spreading the fingers. The opposite action is adduction, which brings a part toward the midline, like lowering the arm back to the body or squeezing fingers together. Abduction is performed by specific muscles known as abductors, such as the deltoid muscle for shoulder movement. In the context of the eyes, abduction means moving the eyeball outward, away from the nose. The other terms given aren’t about movement away from the midline: acoustic relates to hearing, and achromatism refers to color vision deficiency or the absence of color.