Anatomy review for Neurosurgery rotation: angiography
Here is a review of basic arterial angiography of the central nervous system. You will see these images, or images like these, frequently. Impress them on your 10-billion neurons, at least for these two weeks. Annotated arterial angiograms include:
Note the three vessels taking off from the top of the arch from right to left:
Carotid bifurcation in the neck
Note that the internal carotid artery has no branches in the neck, a trick for identifying it when the anatomy is complicated. Also note that the normal initial segment of the internal carotid artery has a diameter about that of the common carotid artery. Use this to compare with stenosis of the internal carotid artery (which typically occurs here).
AP view of internal carotid A in the head
OK, if both L and R anterior cerebral arteries are filling from the L internal carotid artery, which communicating artery must be patent? What is the circle of Willys? These questions are left as an exercise (to quote the old math books).
Lateral view of internal carotid A in the head
The red line shows the top of the "middle cerebral A candelabra," an important landmark in these angiograms. What does the posterior communicating artery connect to? Where does the ophthalmic artery leave the carotid A ?
AP view of vertebrobasilar artery system
OK, of the three main arteries of the posterior fossa, which two branch off the basilar artery? What artery does the other one branch off of? Which one typically causes trigeminal neuralgia? Hemifacial spasm? Obstruction of which artery causes the lateral medullary (Wallenberg) syndrome? Why do neurosurgeons sweat when they get near the basilar tip perforators during aneurysm surgery? Just asking.
lateral view of vertebrobasilar artery system
OK, what nerve runs between the posterior cerebral and superior cerebellar A's? What dural structure? What are the two top differential diagnoses for a painful third nerve palsy? What is a Chiari malformation? What angiographic abnormality is common in Chiari malformations?
A1, A2, M1, M2, etc.
So the middle cerebral artery is divided into M1 and M2 segments by its trifurcation in the Sylvian fissure. Similarly, anterior cerebral artery proximal to the anterior communicating artery is the A1, and distal to the Acom is the A2.
Copyright by G. Rodziewicz, 1996, all rights reserved.