During surgical repair of a supracondylar fracture in a 7-year-old child, the anterior interosseous nerve is inadvertently damaged. Which functional deficit would be expected?

• A Loss of opposition of the thumb
• B Clawing of the ring and little fingers
• C Wasting of the hypothenar muscles
• D Inability to flex the distal phalanx of the index finger and thumb ✓

Explanation

The anterior interosseous nerve (AIN) is a purely motor branch of the median nerve arising in the cubital fossa. It supplies flexor pollicis longus, the lateral half of flexor digitorum profundus (index and middle fingers), and pronator quadratus. Damage results in inability to flex the distal phalanx of the thumb and index finger, producing the characteristic 'pinch' deformity where the patient cannot form a circle with thumb and index fingertip.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.