A patient with ulnar nerve injury at the wrist (Guyon's canal) will show which finding NOT seen with ulnar nerve injury at the elbow?

• A Clawing of ring and little fingers
• B Weakness of hypothenar muscles
• C Intact dorsal cutaneous branch sensation over the dorsum of the hand and little finger ✓
• D Loss of sensation on the palmar aspect of the little and medial ring finger

Explanation

The dorsal cutaneous branch of the ulnar nerve arises 5–7 cm proximal to the wrist (above Guyon's canal) and winds around the ulna to supply the dorsum of the medial hand and little finger. A lesion at Guyon's canal (at the wrist) spares this branch, so dorsal hand sensation is intact. In contrast, an elbow-level ulnar nerve injury involves the nerve before this branch arises, causing loss of both palmar and dorsal sensation. All other features — clawing, hypothenar weakness, and palmar sensory loss — are common to both sites.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.