The Common Cavity Congenital Deformity of the Inner Ear

Congenital deformity of the osseous labyrinth of the inner ear is well recognized as being associated with a fistulous communication with the intracranial subarachnoid space in some cases, leading to meningitis or a spontaneous 'stapes gusher'. Such cases have been described inappropriately as 'Mondini's dysplasia'. We cite 2 patients who both died of meningitis and had an accurate postmortem anatomical appraisal of the deformed temporal bones, one recently described by us and one by Cock more than 150 years ago. The use of eponyms is to be deprecated but should faithfully reflect the original description. The 'common cavity' lesion of the inner ear is a most important precursor of otogenic meningitis readily assessed by computed tomography and needing surgery to prevent the egress of cerebrospinal fluid or ingress of pathogens causing meningitis.