This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Musculoskeletal  disorders, Subject name: Pediatrics
A 9-year old boy with the below features presents with pain in left shoulder and neck, with a restricted range of motion. There is no history of trauma or any surgery. What is the likely diagnosis? 
Select and explain. 
A. Facio scapulo humeral dystrophy, B. Long thoracic nerve palsy, C. Klippel-feil syndrome, D. Becker muscular dystrophy
A: Facio scapulo humeral dystrophy
Answer: A: Facio scapulo humeral dystrophy 
Explanation: Pain in the neck and shoulder with winging of scapula, in a child with no history of trauma or surgery clinches the diganosis of facioscapulohumeral dystrophy. No history of trauma or surgery rules out long thoracic nerve palsy. Facioscapulohhumeral dystrophy: It is an autosomal-dominant disorder. severe weakness is in the facial and shoulder muscles (scapular winging). Flattening of deltoid contour, with wasted biceps and triceps. Calf hyperophy is not a feature but foot drop may be seen. Lumbar lordosis and kyphoscoliosis are common complications, and there is no involvement of cardiac muscles. Ref: nelson textbook of pediatrics 21st edition Pgno: 3647