Dehiscent jugular bulb : CT

 Case Report :43 year male patient presents with complaint of chronic giddiness for HRCT mastoid which showed dominant high riding dehiscent jugular bulb on left side protruding into left middle ear cavity. Jugular bulb could not be made out on right side – likely hypoplastic.Salient points by Dr MGK Murthy, Dr Rajshekhar, Dr GA Prasad. -       The superior border of the jugular bulb normally lies below the hypotympanum of the middle-ear cavity. However, in rare cases the jugular bulb may extend upwards, elevating the floor of the hypotympanum and presenting in the middle-ear space with a thin or absent bony septum. This anomaly is known as a high-riding jugular bulb. A jugular bulb is also considered high-riding if it extends superior to the level of tympanic annulus, or encroaches within 2mm of the internal auditory canal (IAC).-       A high-riding jugular bulb has an intact sigmoid plate - a thin plate of bone separating the jugular bulb from the middle-ear cavity.. If the sigmoid plate is deficient, the bulb is free to protrude into the middle-ear cavity, and is then known as a dehiscent jugular bulb.-       Symptoms - tinnitus and conductive hearing loss, which may be ascribed to turbulent blood flow through the aberrant anatomy resulting in unwanted sound transmission through the middle-ear apparatus.-       Otoscopical...
Source: Sumer's Radiology Site - Category: Radiology Authors: Source Type: blogs