Pars vascularis

The larger posterolateral compartment containing the vagal nerve (and branching Arnold’s nerve), spinal accessory nerve, and the internal jugular vein

Hovelacque (1967) was the first to propose the subdivision of jugular foramen. The foramen is divided by a fibrous or bony septum that joins the jugular spine of the petrous bone to the jugular process of the occipital bone, the anteromedial compartment (pars nervosa), and a posterolateral compartment (pars vascularis).

The larger, posterolateral, “pars vascularis” compartment contains CN X, CN XI, Arnold's nerve (or the auricular branch of CN X involved in Arnold's reflex, where external auditory meatus stimulation causes cough), jugular bulb, and posterior meningeal branch of ascending pharyngeal artery ¹⁾.