This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Head and neck, Subject name: Anatomy
[{'content': 'Passavant ridges is due to contraction of? \nSelect and explain. \nA. Palatoglossus, B. Superior constrictor, C. Middle constrictor, D. Inferior constrictor', 'role': 'user'}, {'content': "Answer: B \nExplanation: Some of the upper fibers of the palatopharyngeus pass circularly deep to mucous membrane of the pharynx and form a sphicter internal to the superior constrictor.these fibres constitute passvant's muscle which on contraction raises a ridge called the passavant's ridge on the posterior wall of the nasopharynx.when the soft palate is elevated it comes in contact with this ridge the two together closing the pharyngeal isthmus between the nasopharynx and the oropharynx. Ref BDC volume 3;6 th edition pg 225", 'role': 'assistant'}]