system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
A 21-year-old man comes to the military base physician for evaluation of progressive discomfort in his right shoulder for the past 4 months. He joined the military 6 months ago and is part of a drill team. In anticipation of an upcoming competition, he has been practicing rifle drills and firing exercises 8 hours a day. Physical examination shows tenderness to palpation and a firm mass in the superior part of the right deltopectoral groove. Range of motion is limited by pain and stiffness. Which of the following is the most likely diagnosis?
assistant
Myositis ossificans