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What is Infection of CNS spreads in inner ear through? and explain in detail?
ANSWER: (A) Cochlear aqueductREF: Dhingra 4th edition page 10Indirect repeat from December 2010Cochlear aqueduct: connects scala tympani to CSFEndolymphatic sac: Endolymphatic duct is formed by the union of two ducts, one each from the saccule and the utricle. It passes through the vestibular aqueduct. Its terminal part is dilated to form endolymphatic sac which lies between the two layers of dura on the posterior surface of the petrous bone. Endolymphatic sac is surgically important. It is exposed for drainage or shunt operation in Meniere's disease.Hyrtle's fissure: Hyrtles fissure also called tympanomeningeal hiatus; it is an embryonic remnant that connects CSF space to middle ear just anterior and inferior to the round window. It runs parallel to cochlear aqueduct. It can be the source of congenital CSF otorrhoea or meningitis from middle ear infections. Normally it gets obliterated.