RESUMEN
Changes in cerebral and extracerebral blood flow in the goat after ligation of the internal maxillary artery and deliberate thrombosis of the extracerebral arteries (buccinator, ethmoidal, and ophthalmic) with thrombin were compared to changes seen in animals after internal maxillary artery ligation only and in normal animals where no surgical manipulations were performed. Blood flow was measured by injecting 51-Cr-labeled microspheres into the internal maxillary artery via a catheter placed into the temporal artery. Analysis of the radioactivity in extracerebral and intracerebral tissues indicated that when the internal maxillary artery is ligated and the extracerebral arteries are thrombosed, virtually all of the blood flow from the carotid artery is destined from the brain. However, if only the internal maxillary artery is ligated nearly one-fourth of the blood flow from the maxillary travels to extra-cerebral tissues. In normal animals, it was determined that only one-fourth of the blood flow in the internal maxillary is destined for the cerebral circulation. Results from this study indicate that if the former method is employed an accurate measure of cerebral blood flow is possible without the complications of extra-cerebral flow. If the latter technique is used care must be taken in evaluating cerebral blood flow since a large component of extra-cerebral blood flow is present.