Cervical Carotid Artery

Background and Purpose A model for cerebral ischemia that requires injection of emboli into the internal carotid artery of the rabbit is commonly used. However, in our experience we have found the anatomy of the cervical carotid to be highly variable. If not appreciated, this may result in unexpectedly high variability in the severity of ischemic injury. We undertook this experimental protocol to determine whether it was possible to characterize the anatomy of the rabbit cervical carotid artery. Methods We examined and recorded the architecture of the cervical carotid arteries of 105 consecutive rabbits involved in experimental protocols to evaluate the role of tissue-type plasminogen activator during embolic stroke. Results Two basic patterns of origin of the internal carotid artery were identified: lateral origin, classified as type I, and dorsomedial origin, classified as type II. In addition, there were three subsequent variations in the origin and morphology of the occipital artery in relation to the internal carotid artery: origin from the external carotid artery (subtype A); origin proximal on the internal carotid artery (subtype B); and origin distal on the internal carotid artery (subtype C). Conclusions The classification of the anatomy of the cervical carotid artery of the rabbit into these easily recognized types will assist those attempting to use this embolization model. Failure to recognize the origin of the occipital artery from the internal carotid artery can result in the misdirection of embolic material into the occipital artery and significantly reduce the effectiveness of this stroke model. (Stroke. 1994; 25:501-503.)