A 10 year old boy has fallen from a tree and injured his right chest. He has pain and difficulty breathing. He is tachypenic and tender with an area of paradoxical chest wall movement on the right side. What is the single most likely diagnosis?

The key is B. Flial chest. [In flial chest multiple adjacent ribs are broken in multiple places, separating a segment, so a part of the chest wall moves independently. Pain, difficulty breathing, tachypnea and tender area of chest wall movement suggest flial chest].