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
Scala tympani and vestibuli is drained by: 
Select and explain. 
A. Aqueduct of cochlea, B. Perilymphatic duct, C. Enolymphatic duct, D. Cochlear ly mphatics
B: Perilymphatic duct
Answer: B: Perilymphatic duct 
Explanation: Ans: B (Perilymphatic duct) Ref: Grays Anatomy 40th EdExplanation:Perilymph:It fills the bony labyrinth (scala tympani & scala vestibule)It is similar to CSFIt is drained by perilymphatic duct into the adjoining subarachnoid spaceEndolymph:It fills the membranous labyrinthHas high K+ and low Na+ similar to intracellular fluidIt is produced by specialized cells in the wall of cochlear ductIt is drained via endolymphatic duct