A 25-year-old man with a single anaesthetic plaque on the left forearm presents with progressive inability to extend the ring and little fingers, with hyperextension at the metacarpophalangeal joints and flexion at the interphalangeal joints of these fingers. Sensation is lost over the medial one and a half digits. Which nerve is involved?
- A Median nerve at the carpal tunnel
- B Radial nerve in the spiral groove
- C Ulnar nerve near the elbow ✓
- D Common peroneal nerve at the neck of fibula
Correct answer: C. Ulnar nerve near the elbow
Explanation
Ulnar nerve palsy weakens the interossei and medial lumbricals, producing the classic ulnar claw hand with hyperextension at the MCP joints and flexion at the IP joints of the ring and little fingers, plus sensory loss over the medial one and a half digits. The ulnar nerve is among the most commonly affected nerves in leprosy and is palpable behind the medial epicondyle. Median nerve lesions cause ape thumb, and common peroneal involvement causes foot drop.
Reference: IAL Textbook of Leprosy, 3rd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.