A patient has a lesion of the median nerve at the wrist (carpal tunnel). Which specific intrinsic hand function is MOST likely to be preserved?
- A Opposition of thumb
- B Abduction of thumb in the plane of the palm
- C Adduction of thumb ✓
- D Flexion of the index finger at the MCP joint via 1st lumbrical
Correct answer: C. Adduction of thumb
Explanation
Adduction of the thumb (adductor pollicis) is supplied by the deep branch of the ulnar nerve, not the median nerve; it is therefore preserved in carpal tunnel syndrome. Opposition (opponens pollicis), abduction in the plane of the palm (abductor pollicis brevis), and the first and second lumbricals (MCP flexion/IP extension of index and middle fingers) are all supplied by the recurrent motor branch of the median nerve and are lost in carpal tunnel syndrome.
Reference: BD Chaurasia's Human Anatomy, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.