Surgical anatomy of the jugular foramen

The complexity of the jugular foramen can be appreciated once its deep location, variability in shape and size, and neurovascular contents are recognized. Safe surgical access to this foramen is hindered by surrounding structures. Structures that traverse the jugular foramen are the sigmoid sinus, inferior petrosal sinus, jugular bulb, glossopharyngeal nerve, vagus nerve, accessory nerve, Jacobson's nerve, Arnold's nerve, meningeal branches of the ascending pharyngeal and occipital arteries, and the cochlear aqueduct. The classic description of the jugular foramen divides this structure into two discrete compartments, the pars nervosa and the pars venosa. However, microanatomical studies have demonstrated that this compartmentalization of the jugular foramen is an oversimplification and has no surgical significance. Instead, it is more useful to describe the petrosal, sigmoid, and intrajugular portions of the jugular foramen. The petrosal portion contains the inferior petrosal sinus. The sigmoid portion receives the sigmoid sinus. The intrajugular portion contains cranial nerves IX, X, and XI. All of the surgical approaches to this region require thorough knowledge of the temporal bone, which forms the lateral, posterior, and superior boundaries of the jugular foramen.