It is associated with carotid cavernous fistula where the internal carotid artery has ruptured inside the cavernous sinus, exposing the venous blood in the sinus to arterial pressures. This causes the venous pressure in the superior ophthalmic vein to be greatly increased and to vary with the arterial pressure, resulting in greatly impaired venous return from the eye and orbit. Back to Question 14 14. Be able to trace blood from the heart to any general area of the brain. Depending on the destination, one could use several different routes to get to the circle of Willis and the cerebral or cerebellar arteries.
All routes start off with the heart and the aorta.
If the area to be supplied with blood is in the anterior part of the brain, then you would use the appropriate common carotid and internal carotid to get to either the anterior or middle cerebral on that side. Of course, you could always start off on the opposite side and cross to the other side using the anterior communicating artery. If the area to be supplied involves the posterior circulation, you would use the appropriate subclavian and vertebral to get blood to the brainstem, cerebellum, and occipital lobes. Using the posterior communicating arteries, you could use the vertebrals to supply the anterior part of the brain, or the internal carotids to supply the posterior part of the brain. The main thing is to be able to draw the circle of Willis and know that both vertebrals and both internal carotids can get blood to it.