Ans. is 'b' i.e.lateral condyle humerus This child had lateral condyle of humerus 4 yrs back. He is now presenting with symptoms of tardy ulnar palsy. Lateral condyle of humerus may lead to cubitus valgus deformity because of diminished growth at the lateral side of distal humeral epiphyses. Cubitus valgus deformity leads to late ulnar palsy (tardy ulnar nerve palsy) because of friction neuritis of the ulnar nerve as it moves over the medial epicondyle every time the elbow is flexed and extended. Ulnar nerve palsy presents as tingling and numbness in the distribution of ulnar nerve.Treatment- Anterior transposition of ulnar nerve.