Compartmental subdivisions of the jugular foramen: a review of the current models.

There is presently no consensus on compartmental subdivision of the jugular foramen (JF) which can complicate planning operations in this area and understanding foraminal tumour growth patterns. The extradural neural axis compartment (EDNAC) may aid in producing a standardised model in the future. This review aims to summarise the models of JF compartmentalisation and analyse how sound they are anatomically.This narrative review has identified the key papers and supporting literature that discussed, referenced or first presented models of JF compartmentalisation.Three intraforaminal components serve as the basis for JF compartmentalisation: the fibro-osseous bridge, the neurovascular contents and the EDNAC. A total of four models have been proposed so far. There exist two-part (bipartite) models by Hovelacque (1934) and Shapiro (1972) and three-part (tripartite) subdivisions by Katsuta (1997) and Bernard (2018).The bipartite model has been criticised as being oversimplified and lacking surgical validity yet support for this compartmentation persists despite the increasing popularity of the tripartite model. The three-part subdivision of Bernard can be considered the most anatomically faithful model to date due to the consideration of the dura and EDNAC. It is important that future studies factor in the entire anatomy of the JF which may generate an anatomically accurate and surgically applicable compartmental model.