MP1600 Circle of Willis
This 3D printed specimen demonstrates the intracranial arteries that supply the brain relative to the inferior portions of the viscero- and neurocranium. This print was created by careful segmentation of angiographic data. The model shows the paired vertebral arteries entering the cranial cavity through the foramen magnum and uniting to form the basilar artery. The basilar can be seen dividing into their terminal posterior cerebral arteries. The superior cerebellar arteries arise just proximal to this termination.
The internal carotid arteries (ICAs) can be traced from the point where they enter the petrous portion of the temporal bone via the carotid canal and travel medially and anteriorly to emerge on the superior margin of the foramen lacerum. It is here that each ICA lies within the cavernous sinus (not shown). The S-shaped carotid siphon on both left and right sides are most beautifully demonstrated lateral to the sella turcica. The ICAs then pass medial to the anterior clinoid processes. We note that (as in up to 30% of individuals) there has been ossification of the ligamentous bridge between the middle clinoid processes and the anterior clinoid process to create a caroticoclinoid foramen. The ICAs then divide into anterior and middle cerebral arteries. The paired posterior communicating arteries are clearly visible connecting the posterior cerebral and middle cerebral arteries. The completion of the Circle of Willis, made by the single anterior communicating artery between the anterior cerebrals arteries is difficult to discern as the anterior cerebral arteries lie so close together.