Congenital sensorineural hearing loss: Mondini's deformity.In the literature, the term Mondini's deformity describes virtually any malformation of the bony labyrinth short of complete aplasia aplasia /apla·sia/ (ah-pla´zhah) lack of development of an organ or tissue.aplas´tic aplasia axia´lis extracortica´lis conge´nita familial centrolobar sclerosis. . Mondini described this anomaly in cases of congenital deafness in which the cochlea cochlea (kŏk`lēə): see ear. was dilated and contained only one to one and a half turns. [1,2] Should inner ear development be interrupted between the fourth and fifth weeks of gestation---after differentiation of the auditory placode into the otocyst otocyst /oto·cyst/ (o´to-sist) the auditory vesicle of the embryo. o·to·cyst n. The structure formed by invagination of the embryonic ectodermal tissue that develops into the inner ear. , but before division of the latter into the primordium primordium /pri·mor·di·um/ (-um) pl. primor´dia [L.] the earliest indication of an organ or part during embryonic development. pri·mor·di·um n. pl. of the cochlea, vestibule, and semicircular canals--a "common cavity" forms that has no internal architecture (figure). [2] In these cases, hearing loss is usually profound. References (1.) Jackler RK, Luxford WM, House WF. Congenital malformations of the inner ear: A classification based on embryogenesis Embryogenesis The formation of an embryo from a fertilized ovum, or zygote. Development begins when the zygote, originating from the fusion of male and female gametes, enters a period of cellular proliferation, or cleavage. . Laryngoscope 1987;97(Suppl 40):2-14. (2.) Swartz JD, Harnsberger HR. The otic capsule and otodystrophies. In: Swartz JD, Harnsberger HR. Imaging of the Temporal Bone. 2nd ed. New York: Thieme Medical Publishers, 1992:192-246. |
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