Pointing index in supracondylar fracture is due to which nerve injury? (D. REPEAT Feb 2014)

Ans: B (Anterior interosseous nerve) Ref: Apley's System of Orthopaedics and Fractures. 9th ed.Explanation:Complications of Supracondylar FracturesNerve injury - 7%.Vascular injury -1%.Most common nerve injured in extension type - Median, nerve especially anterior interosseous branch.Most common nerve injured in flexion type supracondylar fracture - Ulnar nerve.Most common nerve injured iatrogenicaliy {during Kirschner wire application) - Ulnar nerve.Anterior interosseous nerve supplies deep muscles of forearm except medial half of flexor digitorum profundus.Anterior interosseous nerve supplieso Pronator quadratuso Flexor pollicis longuso Lateral half of flexor digitorum longusThe main portion of the median nerve supplies: o Superficial group:>> Pronator teresFlexor carpi radialisPaSmaris longuso Intermediate group:# Flexor digitorum superficialis muscle.Note:Anterior interosseous nerve palsy causes weakness of lateral half of flexor digitorum longus, hence the index finger does not flex at the DIP joint, causing Pointing finger.