This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Ear, Subject name: Anatomy
[{'content': "Vertical crest in fundus of the internal auditary canal is k/a: \nSelect and explain. \nA. Bill's bar, B. Ponticulus, C. Cog, D. Falciform crest", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans is 'a' i.e. Bill's Bar The internal acoustic canal is divided by transverse crest (or falciform crest) into a superior and inferior Part. The superior part is divided by vertical crest or Bill's bar into anterior and posterior parts. Antero-superior part transmits-facial nerve and nervus intermediusPostero-superior part transmits-superior vestibular nerveInferior part transmits-- cochlear nerve lying antero- inferiorly - inferior vestibular nerve postero-inferiorly Bill's bar is used as a surgical landmark for facial nerve identification during Tran's labyrinthine surgery.", 'role': 'assistant'}]