Abstract
A 72-year-old man showed the right frontal artery sign and contralateral external carotid artery sign after a hemiplegic insult. The pulsation of his left angular artery was more prominent than the right. In addition to a complete occlusion of the right common carotid artery, cerebral angiography revealed crossed anastomosis between the left superficial temporal artery and the right frontal artery with a retrograde filling of the right internal carotid artery via the right ophthalmic artery. CT scan of the brain showed widespread hypodense areas in the right hemisphere. After recenalization of the right external carotid artery, the external carotid artery sign was now positive on the right, and the right frontal artery was found anastomosed with bilateral superficial temporal arteries. The right angular artery pulsation was more prominent than the left.
Both of the frontal artery sign and the external carotid artery sign were reported as a bedside indicator of internal carotid occlusion, usually positive on the side of occlusion. In the case of frontal artery sign with contralateral external carotid artery sign, this syndrome, suggesting one of the crossed external carotid-internal carotid collaterals, will be a diagnostic indicator of common carotid artery occlusion.
