Anatomy of the Jugular Foramen

The normal jugular foramen averages 15 mm in length and 10 mm in width, and the smaller pars nervosa averages 5 mm in width.1 There is a marked range in the dimensions and degree of asymmetry of the jugular foramen, due mainly to the pars vascularis. The right jugular vein and foramen are usually dominant.1

The glossopharyngeal, vagus, and cranial accessory nerves emerge in a line from along the medulla oblongata and then run laterally to the jugular foramen, where they leave the posterior cranial fossa through the jugular foramen. DiChiro et al.1 describe the foramen as a canal coursing anteriorly, inferiorly, and laterally from an intracranial to an extracranial opening. A fibrous or bony septum separates the pars nervosa, containing the petrosal sinus and glossopharyngeal nerve, from the pars vascularis, containing the vagus and the accessory nerves along with the jugular vein.

The jugular foramen is anatomically significant, as it not only acts as a conduit for vital neurovascular structures, but is

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