This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Infection of CNS spread in inner ear is through: 
Select and explain. 
A. Cochlear aqueduct, B. Endolymphatic sac, C. Vestibular aqueduct, D. Hyl fissure
A: Cochlear aqueduct
Answer: A: Cochlear aqueduct 
Explanation: Cochlear aqueduct (Aqueduct of Cochlea) is a connection between scala tympani (containing perilymph) and the subarachnoid space (containing CSF). On occassions, paicularly in young children, the Cochlear aqueduct is large and open.Infection can spread to the inner ear from the infected CSF or vice versa, the cochlear aqueduct resulting in severe profound hearing loss (meningitic labyrinthitis).