C8 nerve root corresponds to which finger movement?

C8 nerve root corresponds to which finger movement?

• A. Finger extension—Middle finger
• B. Finger flexion—Ring, little fingers
• C. Wrist flexion
• D. Finger abduction—Medial arm

Answer: (B)

The movement most closely tied to the C8 nerve root is finger flexion of the ring and little fingers. C8 contributes to the ulnar-nerve–innervated muscles that flex the distal joints of these digits (the ring and little fingers), so weakness here points to C8 involvement. In practice, testing this myotome involves asking the patient to curl these fingers toward the palm against resistance. By contrast, finger extension of the middle finger aligns more with the C7 level, and wrist flexion is primarily a C6 (with some C7) function. Finger abduction involves multiple contributions, but the defining C8-related action for this question is the flexion of the ring and little fingers.

The movement most closely tied to the C8 nerve root is finger flexion of the ring and little fingers. C8 contributes to the ulnar-nerve–innervated muscles that flex the distal joints of these digits (the ring and little fingers), so weakness here points to C8 involvement. In practice, testing this myotome involves asking the patient to curl these fingers toward the palm against resistance. By contrast, finger extension of the middle finger aligns more with the C7 level, and wrist flexion is primarily a C6 (with some C7) function. Finger abduction involves multiple contributions, but the defining C8-related action for this question is the flexion of the ring and little fingers.