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': 'Mastoid fontanelle after ossification exists in adults as , \nSelect and explain. \nA. Lambda, B. Asterion, C. Bregma, D. Pterion', 'role': 'user'}, {'content': 'Answer: B \nExplanation: The asterion is the point where the parietomastoid, occipitomastoid and lambdoid sutures meet. In infants the asterion is the site of the posterolateral or mastoid fontanelle,which closes at the end of the first year.', 'role': 'assistant'}]