Which are the primary wrist flexors?

• A. Flexor carpi radialis, flexor carpi ulnaris, and palmaris longus
• B. Extensor carpi radialis longus
• C. Flexor digitorum superficialis
• D. Extensor carpi ulnaris

Answer: (A)

Wrist flexion is produced primarily by muscles that cross the wrist on the palm side. The main players are the flexor carpi radialis, flexor carpi ulnaris, and palmaris longus. Flexor carpi radialis attaches to the bases of the second and third metacarpals and flexes the wrist while also aiding radial deviation. Flexor carpi ulnaris attaches to the pisiform and base of the fifth metacarpal, flexing the wrist and aiding ulnar deviation. Palmaris longus, when present, tenses the palmar fascia and assists in wrist flexion. The other muscles listed are either extensors (which extend the wrist) or primarily finger flexors (with only limited wrist flexion assistance), so they don’t serve as the primary wrist flexors.