Which cranial nerves are supplied by the neuromeningeal trunk of the ascending pharyngeal artery?

Cranial Nerves Supplied by the Neuromeningeal Trunk of the Ascending Pharyngeal Artery

The neuromeningeal trunk of the ascending pharyngeal artery primarily supplies cranial nerves IX (glossopharyngeal), X (vagus), XI (spinal accessory), and XII (hypoglossal).

Anatomical Basis

The ascending pharyngeal artery (APA) is a small but clinically significant branch of the external carotid artery that plays a crucial role in supplying various neurovascular structures in the head and neck region. It typically originates as the third branch of the external carotid artery, with an average distance of 15.3 mm from the common carotid bifurcation 1.

The APA divides into two main trunks:

1. The pharyngeal trunk - supplying the pharyngeal structures
2. The neuromeningeal trunk - supplying neural structures

Neuromeningeal Trunk Distribution

The neuromeningeal trunk has specific branches that supply the lower cranial nerves through their respective foramina:

• Hypoglossal branch - enters the hypoglossal canal to supply CN XII
• Jugular branch - enters the jugular foramen to supply CN IX, X, and XI
• Clival branches - supply the dura of the clivus and potentially anastomose with meningeal branches

Clinical Significance

Understanding the vascular supply to these cranial nerves is essential for:

1. Diagnostic imaging interpretation - When evaluating cranial neuropathies involving the lower cranial nerves, the territory of the neuromeningeal trunk should be carefully assessed 2.

2. Endovascular procedures - During embolization procedures involving the APA, particular attention must be paid to avoid inadvertent embolization of branches supplying cranial nerves 3.

3. Surgical planning - Knowledge of the vascular supply to cranial nerves helps prevent ischemic injury during skull base procedures 4.

Imaging Considerations

When evaluating pathologies potentially involving these cranial nerves:

• MRI is the gold standard for evaluating cranial nerve anatomy and pathology 2.
• High-resolution sequences should extend from the brainstem nuclei to the end organs.
• Contrast enhancement is imperative for optimal visualization of the nerves and their vascular supply.

Potential Pitfalls

• The anatomy of the APA and its branches is highly variable, requiring careful assessment in each individual case.
• The neuromeningeal trunk may form anastomoses with intracranial vessels, creating potential routes for embolic complications during interventional procedures 5.
• Cranial nerve deficits can occur despite anatomic preservation of the nerve if its vascular supply is compromised 4.

Understanding the relationship between the neuromeningeal trunk of the ascending pharyngeal artery and cranial nerves IX-XII is crucial for accurate diagnosis and safe treatment of pathologies in this region.