Anatomy Eye, Nose and Ear 59e6ea8e Perilymph enters the subarachnoid space the A Cochlear duct B Ductus Reuniens C Perilymphatic Duct D Vestibular Aqueduct High-Yield Explanation C. The perilymph enters the subarachnoid space of the posterior cranial fossa the cochlear aqueduct, which contains the perilymphatic duct.