Jugular Bulb Anatomy for Lateral Skull Base Approaches

Background: This study was designed to define the detailed anatomical relations of the jugular bulb with the facial nerve, sigmoid sinus, otic capsule, and internal acoustic canal allowing the safe management of the jugular bulb. Methods: Thirty-five formalin-perfused cadaveric temporal bones that had well mastoid and petrous pneumatization without any neurovascular variations on computed tomography scan were selected for the study. The bones were dissected via translabyrinthine approach. Results: The dome of the jugular bulb was located under the facial nerve in 21 of the cases (60%), in the mastoid cavity in 8 of the cases (22.9%), and in the tympanic cavity in 6 of the cases (17.1%). Significant difference was observed only between the temporal bones in which the dome of the jugular bulb was located in the mastoid cavity and under the facial nerve with regard to the mastoid cortex-lateral semicircular canal measurement (P = 0.04). Conclusion: Because of the high variability of the position of the dome of the jugular bulb, the precise knowledge of the relations of the jugular bulb and the preoperative radiologic verification of possible variations are essential to avoid the problems associated with its position and to decide the approach individually.