%0 Journal Article %A M.-L. Ho %A G. Moonis %A C.F. Halpin %A H.D. Curtin %T Spectrum of Third Window Abnormalities: Semicircular Canal Dehiscence and Beyond %D 2017 %R 10.3174/ajnr.A4922 %J American Journal of Neuroradiology %P 2-9 %V 38 %N 1 %X SUMMARY: Third window abnormalities are defects in the integrity of the bony structure of the inner ear, classically producing sound-/pressure-induced vertigo (Tullio and Hennebert signs) and/or a low-frequency air-bone gap by audiometry. Specific anatomic defects include semicircular canal dehiscence, perilabyrinthine fistula, enlarged vestibular aqueduct, dehiscence of the scala vestibuli side of the cochlea, X-linked stapes gusher, and bone dyscrasias. We discuss these various entities and provide key examples from our institutional teaching file with a discussion of symptomatology, temporal bone CT, audiometry, and vestibular-evoked myogenic potentials.EVASenlarged vestibular aqueduct syndromeSSCCDsuperior semicircular canal dehiscence %U https://www.ajnr.org/content/ajnr/38/1/2.full.pdf