When the Jugular Bulb Contacts the Facial Nerve.

Dehiscences of the intrapetrous canal of the facial nerve (FN) and those of a high jugular bulb (HJB) have various incidences. However, the HJB-FN common dehiscent osseous wall is a scarce finding and rarely reported. Thus, this work aimed to study this peculiar intrapetrous morphology on computed tomograms (CTs). A batch of 60 archived CTs was used. In 28.33% of cases, no HJBs were found; in 51.67% of cases, there were unilateral HJBs, and in 20% of cases, bilateral HJBs were found. 83.87% of the unilateral HJBs were on the right side, and the rest on the left side. In 3 cases with right-sided HJBs, 1 male and 2 females, FNs were found directly contacting the HJB. Therefore, the contact HJB-FN occurred in 5% of cases and 2.5% of the petrous bones/sides. HJBs' dehiscences to the retrotympanum or the posterior cranial fossa were also found in those cases. A dehiscent posterior semicircular canal to the HJB was found in one of these. Incidences for the HJB and the HJB-FN contacts seem higher than in previous studies. However, as only a 60-case batch of study was used, an overestimation may have resulted. Although scarce, the HJB-FN contact could determine specific symptoms and must be documented before specific surgical procedures involving the mastoid, retrotympanum, and posterior cranial fossa.