The C5 nerve root is most closely associated with which movement?

The C5 nerve root is most closely associated with which movement?

• A. Shoulder abduction
• B. Wrist extension
• C. Elbow flexion
• D. Finger abduction

Answer: (A)

Shoulder abduction is the movement most closely tied to the C5 nerve root. C5 primarily contributes to the deltoid and supraspinatus muscles, which lift the arm away from the body. The initial 15 degrees of abduction come from supraspinatus (C5), and the remainder relies on the deltoid (C5–C6), making this movement the best match for the C5 root. Wrist extension is mainly a C6 function via the extensor muscles of the forearm. Elbow flexion involves the biceps and other muscles innervated by C5–C6. Finger abduction is governed largely by intrinsic hand muscles innervated by the ulnar nerve (T1), not C5.

Shoulder abduction is the movement most closely tied to the C5 nerve root. C5 primarily contributes to the deltoid and supraspinatus muscles, which lift the arm away from the body. The initial 15 degrees of abduction come from supraspinatus (C5), and the remainder relies on the deltoid (C5–C6), making this movement the best match for the C5 root.

Wrist extension is mainly a C6 function via the extensor muscles of the forearm. Elbow flexion involves the biceps and other muscles innervated by C5–C6. Finger abduction is governed largely by intrinsic hand muscles innervated by the ulnar nerve (T1), not C5.