Which hand muscles are primarily responsible for abduction and adduction of the fingers?

Which hand muscles are primarily responsible for abduction and adduction of the fingers?

• A. Interossei
• B. Lumbricals
• C. Thenar
• D. Hypothenar

Answer: (A)

Interossei are the hand muscles that move the fingers toward or away from the midline. The dorsal interossei abduct (spread) fingers away from the middle finger, while the palmar interossei adduct (pull) fingers toward the middle finger. This is their primary role for digits 2–5. In contrast, lumbricals mainly flex the metacarpophalangeal joints and extend the interphalangeal joints, not moving the digits side-to-side. The thenar muscles move the thumb, and the hypothenar muscles move the little finger, but neither group handles finger abduction or adduction. So the interossei are the ones responsible for the finger ab/adduction movements.

Interossei are the hand muscles that move the fingers toward or away from the midline. The dorsal interossei abduct (spread) fingers away from the middle finger, while the palmar interossei adduct (pull) fingers toward the middle finger. This is their primary role for digits 2–5. In contrast, lumbricals mainly flex the metacarpophalangeal joints and extend the interphalangeal joints, not moving the digits side-to-side. The thenar muscles move the thumb, and the hypothenar muscles move the little finger, but neither group handles finger abduction or adduction. So the interossei are the ones responsible for the finger ab/adduction movements.