This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Elbow injuries, Subject name: Orthopaedics
A child with Supracondylar fracture is unable to flex his interphalangeal joint of thumb. Which nerve is most likely injured ? 
Select and explain. 
A. Median nerve, B. Deep branch of ulnar nerve, C. Posterior Interosseus nerve, D. Anterior Interosseus nerve
D: Anterior Interosseus nerve
Answer: D: Anterior Interosseus nerve 
Explanation: Flexion at Interphalyngeal joint of thumb caused by FlexorPollicisLongus which us supplied by anterior Interosseus nerve a branch of median nerve . Anterior Interooseus nerve is the most commonly injured nerve in Supracondylar humerus fracture Refer : maheswari 9th ed