Location and Course
The ascending pharyngeal artery arises from the posterior (or medial, depending on classification) aspect of the external carotid artery. Its site of origin is located near the bifurcation of the common carotid artery.
Vascular Topography:
- Lies adjacent to the posterior wall of the fascial sheath of the external carotid artery.
- Ascends along the lateral wall of the pharynx.
- Located medial to the stylopharyngeus muscle.
- Passes in close proximity to the tonsillar fossa (fossa tonsillaris), where the ascending pharyngeal and facial arteries run nearby.
Branches of the Artery
Along its course, the main trunk gives off several branches supplying various head and neck structures:
- Pharyngeal branches (rr. pharyngeales) — course toward the pharyngeal wall and palatine tonsil.
- Posterior meningeal artery (a. meningea posterior) — an accessory source of blood supply to the dura mater, forming numerous anastomoses with the primary source, the middle meningeal artery (a. meningea media).
- Inferior tympanic artery (a. tympanica inferior) — courses toward the medial wall of the tympanic cavity.
Blood Supply to the Pharynx
The ascending pharyngeal artery acts as the main artery of the pharyngeal wall. However, the blood supply to this organ is complex and derived from multiple sources.
- Arterial Supply: In addition to the a. pharyngea ascendens, the pharynx receives contributions from branches of the facial (a. facialis), maxillary (a. maxillaris), and superior thyroid (a. thyroidea superior) arteries. The palatine tonsil receives blood from pharyngeal branches and the ascending palatine artery (a branch of the facial artery).
- Venous and Lymphatic Drainage: Venous blood drains into the pharyngeal plexus (plexus pharyngeus) and subsequently into the internal jugular vein (v. jugularis interna). Lymph drains into the cervical lymph nodes.
- Innervation: The pharyngeal plexus is formed by branches of the glossopharyngeal (n. glossopharyngeus) and vagus (n. vagus) nerves, along with sympathetic fibers.
Blood Supply to the Tympanic Cavity
Via its branch—the inferior tympanic artery (a. tympanica inferior)—the ascending pharyngeal artery supplies the medial wall of the tympanic cavity. The walls of this cavity receive blood from a network of vessels originating from different vascular beds:
- a. tympanica anterior (from the maxillary artery);
- r. caroticotympanicus (from the internal carotid artery);
- a. tympanica superior (from the middle meningeal artery);
- a. tympanica posterior (from the stylomastoid artery, a. stylomastoidea);
- a. tympanica inferior (from the ascending pharyngeal artery).
Clinical Significance
- Pharyngeal Surgery (Tonsillectomy): The topography of the ascending pharyngeal and facial arteries near the pharyngeal wall corresponding to the fossa tonsillaris is clinically relevant during palatine tonsil removal.
- Cerebral Collateral Circulation: In internal carotid artery (ICA) stenosis, blood can flow from the external carotid artery system into the ICA distal to the obstruction site, ensuring continuous brain perfusion. One such collateral pathway involves anastomoses between the ascending pharyngeal artery and meningeal branches of the ICA.
- Angiographic Feature: Due to their small caliber, these tiny arteries are not individually visible on angiograms. They are collectively referred to as the inferolateral trunk.