A patient with an isolated median nerve laceration at the wrist presents with inability to oppose the thumb and decreased sensation over the lateral 3½ fingers. Which intrinsic muscle is MOST critical for opposition and is denervated?

• A Abductor pollicis longus
• B Adductor pollicis
• C Opponens pollicis ✓
• D First dorsal interosseous

Explanation

Opposition of the thumb — the most important functional movement of the thumb — is primarily performed by opponens pollicis (thenar eminence), which is innervated by the recurrent branch of the median nerve. Loss of median nerve function at the wrist causes thenar wasting and inability to oppose. Abductor pollicis longus (APL) is innervated by the posterior interosseous nerve (radial nerve branch) and abducts/extends the thumb metacarpal. Adductor pollicis is innervated by the ulnar nerve and adducts the thumb; its intact function in median nerve palsy allows the Froment's sign to manifest. First dorsal interosseous is ulnar nerve innervated.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.