Most potential route for spread of infection from CNS to inner ear
Vestibular aqueduct
Cochlear aqueduct
Endolymphatic sac
Hyle fissure
Cochlear aqueduct is most potential route for spread of infection from CNS to inner earQ Cochlear aqueduct & vestibular aqueduct are 2 bony channels (canals) that connect inner ear (cochlea & vestibule respectively) to intracranial sub arachnoid space. Vestibular aqueduct contains endolymphatic duct filled with endolymph, which does not communicate freely with CSF as it ends in a cul de sac and forms a closed space. Whereas perilymph filled cochlear aqueduct is in direct continuation with the CSF which makes it a most potential route of infection. Hyle's fissure is present in early embryonic life that normally obliterates by 24 weeks of gestation. When persistent it provides a connection from middle ear to subarachnoid space.