Which combination describes wrist flexion?

Which combination describes wrist flexion?

• A. Flexor carpi radialis and flexor carpi ulnaris, without assistance.
• B. Flexor carpi ulnaris and palmaris longus.
• C. Flexor carpi radialis and palmaris longus.
• D. Flexor carpi radialis and flexor carpi ulnaris, assisted by palmaris longus.

Answer: (D)

Wrist flexion is produced by muscles that cross the wrist and pull the hand toward the forearm. The two primary flexors are flexor carpi radialis and flexor carpi ulnaris; contracting together, they bend the wrist and balance sideways deviation (one tends to pull toward the thumb side, the other toward the little finger side), so the movement is a true flexion with minimal lateral drift. Palmaris longus is a weaker contributor, but when present it can assist by adding a little extra flexion and by tensing the palmar fascia, which can aid grip. Therefore, the most complete description of wrist flexion involves the two main flexors working together, with palmaris longus providing additional assistance when it is available.

Wrist flexion is produced by muscles that cross the wrist and pull the hand toward the forearm. The two primary flexors are flexor carpi radialis and flexor carpi ulnaris; contracting together, they bend the wrist and balance sideways deviation (one tends to pull toward the thumb side, the other toward the little finger side), so the movement is a true flexion with minimal lateral drift. Palmaris longus is a weaker contributor, but when present it can assist by adding a little extra flexion and by tensing the palmar fascia, which can aid grip. Therefore, the most complete description of wrist flexion involves the two main flexors working together, with palmaris longus providing additional assistance when it is available.