A high riding jugular bulb is distinguished from an asymmetrically large jugular bulb by its dome (roof) reaching above the internal acoustic meatus (IAM). It need not be larger than the contralateral bulb, but usually is.
A run of the mill high riding jugular bulb has an intact sigmoid plate - a thin plate of bone separating the jugular bulb from the middle ear cavity. This can only be appreciated on thin slice bone algorithm CT, and is too thin to appreciate on MRI.
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- 2. Swartz J, Harnsberger H. Imaging of the temporal bone. Georg Thieme Verlag. ISBN:0865777004. Read it at Google Books - Find it at Amazon