Jugular bulb anatomical variations and pneumatization patterns: a comprehensive CBCT analysis

Abstract

Purpose This study aims to assess the anatomical possibilities of the jugular bulb (JB). Methods Fifty archived CBCT scans were analyzed. Results The average distance between the internal acoustic canal (IAC) and the JB was 7.97 mm on both sides (Right: SD = 2.56 mm, range 3.16–13.3 mm; Left: SD = 2.5 mm, range 2.9–13.6 mm). JB walls’ pneumatization was classified into eight patterns. Deep petrosal cells (DPCs) prevailed in the lateral wall of the JB. The absence of pneumatization (NP) was commonly found on the left side. The presence of infralabyrinthine and hypotympanic cells varied. Less common types included accessory occipital cells (AOCs), posteromedial tracts (PMTs), and basi-occipital cells (BOCs), which determined a consistent variation of the lateral wall pneumatization patterns. Pneumatization of the medial wall was not observed in 50 right sides and 49 left sides. The inferior wall analysis revealed symmetry in AOC distribution and a predominant occurrence of NP. Cases with hypotympanum (HT) in the lateral wall showed a statistically significant IAC-JB distance increase by an average of 4.67 mm compared to NPs. Specific pneumatizations, particularly HT on the lateral side, have a significant effect on the IAC-JB distance, showing a clear pattern of increasing distance from DPC to NP and then to HT. A significant distance increase in HT pneumatization was noted. There were also recorded instances of JB hypoplasia and hyperplasia, JB diverticula, dehiscent JBs, and high JBs. Conclusion This study establishes a novel classification of JB pneumatizations to aid in the understanding of the temporal bone anatomy.