[The "dangerous loop" of the internal carotid artery. An anatomic study].

Variations of the clinical course of the internal carotid artery in the parapharyngeal space were studied in order to define possible causes of acute hemorrhage during pharyngeal surgery. Four cases of sigmoid tortuosity involving the internal carotid artery were found in a total of 81 dissected carotid sheathes and 8 corrosion casts. In 2 cases the internal carotid artery was located in direct contact with the tonsillar fossa to form a clinically unsafe carotid tortuosity that was considered at risk during tonsil surgery.