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: Unknown
[{'content': 'Retropharyngeal space extends from base of skull to: \nSelect and explain. \nA. Hyoid bone, B. Bifurcation of trachea, C. Angle of mandible, D. Cricoid cartilage', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Retropharyngeal space: It lies behind the pharynxbetween the buccopharyngeal fascia covering pharyngeal constrictor muscles and the pre vertebral fascia.\nIt extendsfrom the base of skull to the bifurcation of trachea.\nThespace is divided into two lateral compartments (spaces ofGillette) by a fibrous raphe.\nEach lateral spacecontains retropharyngeal nodes which usually disappear at3-4 years of age.\nParapharyngeal space communicates withthe retropharyngeal space.\nInfection of retropharyngealspace can pass down behind the oesophagus into themediastinum .', 'role': 'assistant'}]