Jugular foramen

Location and formation

The jugular foramen is located between the occipital and temporal bones. It connects the posterior cranial fossa to the external base of the skull and is visualized on a macerated skull from the inferior (basal) view.

The foramen is formed by the union of two bony structures:

• Jugular notch (Incisura jugularis) — located on the outer margin of the lateral part of the occipital bone.
• Petrous part of the temporal bone.

Posterior to the jugular notch is the jugular process (Processus jugularis). Anterior to it projects the intrajugular process (Processus intrajugularis), which separates the veins and nerves within the foramen.

What passes through the jugular foramen?

The structures of the unified "vagal system" pass through the foramen—mixed cranial nerves sharing common nuclei in the brainstem:

• Glossopharyngeal nerve (Nervus glossopharyngeus, cranial nerve IX) — exits the skull, then passes between the internal carotid artery and the jugular vein, heading toward the stylopharyngeus muscle.
• Vagus nerve (Nervus vagus, cranial nerve X) — exits the skull together with the accessory nerve.
• Accessory nerve (Nervus accessorius, cranial nerve XI) — its spinal roots first ascend into the cranial cavity through the foramen magnum, join the cranial roots, and then the common trunk exits the skull through the jugular foramen. After exiting, the spinal part forms the external branch, while the cranial part joins the vagus nerve.
• Meningeal branch of the vagus nerve — branches off from the superior cervical ganglion, passes through the jugular forum, and innervates the dura mater of the posterior cranial fossa.
• Posterior meningeal artery — enters the cranial cavity through the jugular foramen and supplies blood to the dura mater of the posterior cranial fossa.

Topography of nerve ganglia

The sensory ganglia of the cranial nerves passing through are located in the region of the jugular foramen:

• Ganglia of the glossopharyngeal nerve — superior and inferior.
• Ganglia of the vagus nerve — superior (jugular) and inferior (nodose).

Central processes of the ganglionic cells responsible for general sensation terminate in the sensory nucleus of the solitary tract (n. tractus solitarius).

Clinical significance

Unilateral damage to the external branch of the accessory nerve after its exit from the jugular foramen causes flaccid paralysis of the entire sternocleidomastoid muscle and the upper part of the trapezius muscle.

To examine the function of the accessory nerve, the patient is asked to turn or tilt the head, as well as elevate the shoulders against the examiner's resistance.

Class and exam questions

What else to study on this topic

• Posterior cranial fossa
• External cranial base
• Vagus nerve (cranial nerve X)
• Accessory nerve (cranial nerve XI)
• Glossopharyngeal nerve (cranial nerve IX)

Other topics in the "Anatomical Structures" section

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.