This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Anatomy
[{'content': 'True about clavicle? \nSelect and explain. \nA. Endochondral ossification, B. Veical, C. No medullary cavity, D. Rarely fractures', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans:C.)No medullary cavity. Peculiarities of Clavicle: It has no medullary cavity It is the first bone to ossify in the fetus (5th-6th week) It is the only long bone having 2 primary centers of ossification (others have only 1) It is the only long bone that ossifies in membrane and not in cailage It is the only long bone lying horizontally It is the most common fractured long bone in the body It is subcutaneous throughout', 'role': 'assistant'}]