Which muscle primarily extends the wrist?

Which muscle primarily extends the wrist?

• A. Extensor Carpi Radialis Longus
• B. Flexor Carpi Radialis
• C. Palmaris Longus
• D. Flexor Digitorum Profundus

Answer: (A)

Wrist extension is produced by muscles on the back of the forearm that pull the hand straight back at the wrist. Among the options, Extensor Carpi Radialis Longus is primarily responsible for extending the wrist. It runs from the humerus to the base of the second metacarpal, so its contraction straightens the wrist and can also help move the hand toward the thumb side (radial deviation). The other muscles are not wrist extenders by primary action: Flexor Carpi Radialis flexes the wrist (and lightly abducts), Palmaris Longus is a weak wrist flexor, and Flexor Digitorum Profundus mainly flexes the fingers (with only minor wrist involvement).

Wrist extension is produced by muscles on the back of the forearm that pull the hand straight back at the wrist. Among the options, Extensor Carpi Radialis Longus is primarily responsible for extending the wrist. It runs from the humerus to the base of the second metacarpal, so its contraction straightens the wrist and can also help move the hand toward the thumb side (radial deviation). The other muscles are not wrist extenders by primary action: Flexor Carpi Radialis flexes the wrist (and lightly abducts), Palmaris Longus is a weak wrist flexor, and Flexor Digitorum Profundus mainly flexes the fingers (with only minor wrist involvement).