Petrous high jugular bulb: A histological study

Purpose: A high jugular bulb (JB) is thought to affect structures of the inner ear and possibly cause symptoms there, but clear histological findings of an anatomical relationship between a high JB and the inner ear have not yet been described. Materials and Methods: We surveyed horizontal sections of 1,591 temporal bones from the collection of the Otopathology Laboratory at the University of Minnesota in Minneapolis, Minnesota, defining a high JB as a JB extending above the inferior margin of the basal cochlear turn. Results: In 65 specimens (16%), we found a high JB with its vascular wall obviously thinner than that of a low JB. Bony resorption was occasionally observed around high JBs. Sixteen specimens showed a bony deshiscence between the JB and the endolymphatic sac. Clinical charts showed no obvious symptoms associated with a high JB. Conclusions: Our findings suggest that the JB may have potential to expand upward postnatally. Although our study confirmed occasional bony dehiscence between the JB and the endolymphatic sac, JBs with this involvement may have only a minor effect on function in the inner ear. (Am J Otolaryngol 2000;21:161-168. Copyright (C) 2000 by W.B. Saunders Company).