This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Oral Cavity, Subject name: ENT
[{'content': 'Trismus in CA of temporal bone occurs due to involvement of- \nSelect and explain. \nA. Dura, B. Temporo mandibular joint, C. Mastoid, D. Eustachian tube', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Temporo mandibular joint Clinical Assessment of Temporal bone Tumorso A long history of ear discharge suggests cancer associated with inflammatory ear disease (Maijolins ulcer)o Pulsatile tinnitus suggests tumor of vascular origin such as glomus tumor or a middle ear vascular anamoly; or a duralarteriovenous abnormality.o Deep headache raises the suspicion of dural involvement.o Facial weakness indicates invasion of the facial nerveo Onset of vertigo and sensineuronal hearing loss indicates involvement of the labyrinth and the development of speech and swallowing problems heralds involvement of the lower cranial nerves in the jugular foramen.o The onset of trismus due to the involvement of temporomandibular joint, pterygoid muscles or mandible suggests advanced disease that has spread anteriorly. Also the appearance of perauricular and parotid swelling is a grave sign.", 'role': 'assistant'}]