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
Vertical crest in fundus of the internal auditary canal is k/a: 
Select and explain. 
A. Bill's bar, B. Ponticulus, C. Cog, D. Falciform crest
A: Bill's bar
Answer: A: Bill's bar 
Explanation: 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.