A tube leading from the tympanic cavity to the nasopharynx; it consists of an osseous (posterolateral) portion at the tympanic end, and a fibrocartilaginous (anteromedial) portion at the pharyngeal end; where the two portions join, in the region of the sphenopetrosal fissure, is the narrowest portion of the tube (isthmus); the auditory tube enables equalization of pressure within the tympanic cavity with ambient air pressure, referred to commonly as "popping of the ears".
Synonym: tuba auditiva, tuba auditoria, eustachian tube, guttural duct, otopharyngeal tube, otosalpinx, pharyngotympanic tube, salpinx, tuba acustica, tuba eustachiana, tuba eustachii.
(05 Mar 2000)