The ascending pharyngeal artery of the dog was investigated by means of the acryl plastic injection method. This artery usually arose from the external carotid artery, sometimes from the occipital, the posterior auricular, or rarely the ascending palatine of the lingual artery. It ran forwards between the vagus and hypoglossal nerves and continued anteromedially up to the posterolateral wall of the pharynx at the superior margin of the thyropharyngeus muscle, in contact with the inferomedial end of the tympanic bulla. En route it gave rise to the thyropharyngeal, the stylopharyngeal and the styloglossal branches, sometimes additionally the inferior cervical, the digastric and the palatine branches, although all these branches were not observed when it arose from the lingual. It reached to the inferomedial end of the foramen caroticum extemum after giving rise to twigs to the pharyngeal mucosa between the pharyngeal opening of the auditory tube and the pharyngeal isthmus, and the stylopharyngeal, the hypopharyngeal, the levator veli palatine, the thyropharyngeal and the styloglossal branches between the stylopharyngeus and the styloglossus muscles and inferomedial to the tympanic bulla. From this position, the ascending pharyngeal passed above the opening of the auditory tube in about half of all examples observed towards this foramen, but did not intertwine around the loop of the internal carotid. Rarely, it anastomosed with the inferoanterior end of the loop. The main stem of this artery ran forwards between the pterygoid process and the superior wall of the nasopharynx, and gave off small twigs anastomosing with the opposite fellows in the mucosa of the pharyngeal fornix. Finally, it was distributed to the mucosa around the choanae beyond the pterygopalatine suture. In one case, it terminated on the superior margin of the thyropharyngeus muscle, and a branch arising from the loop of the internal carotid divided into the anterior and posterior twigs. The former supplied the mucosa of the nasopharynx, while the latter the levator veli palatini, the thyropharyngeus and the thyroglossus muscles. In conclusion, it can be said that this artery of the dog never contributed to the blood supply of the brain at all, although the ascending pharyngeal of some carnivorae actually constituted a collateral route of the internal carotid, and has probably been presented as a similar vessel in the embryological period of other species.
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