Curving and looping of the internal carotid artery in relation to the pharynx: frequency, embryology and clinical implications

Variations of the course of the internal carotid artery in the parapharynge al space and their frequency were studied in order to determine possible ri sks for acute haemorrhage during pharyngeal surgery and traumatic events, a s well as their possible relevance to cerebrovascular disease. The course o f the internal carotid artery showed no curvature in 191 cases, but in 74 c ases it had a medial, lateral or ventrocaudal curve, and 17 preparations sh owed kinking (12) or coiling (5) out of a total of 265 dissected carotid sh eaths and 17 corrosion vascular casts. In 6 cases of kinking and 2 of coili ng, the internal carotid artery was located in direct contact with the tons illar fossa. No significant sex differences were found. Variations of the i nternal carotid artery leading to direct contact with the pharyngeal wall a re likely to be of great clinical relevance in view of the large number of routine procedures performed. Whereas coiling is ascribed to embryological causes, curving is related to ageing and kinking is thought to be exacerbat ed by arteriosclerosis or fibromuscular dysplasia with advancing age and ma y therefore be of significance in relation to the occurrence of cerebrovasc ular symptoms.