This chapter, the second of three showing sections of entire human brains, illustrates axial planes approximating those used in computed tomography scans (see Chapter 9 ). Forebrain structures continue to be emphasized, but parts of the brainstem and cerebellum are indicated as well. The organization of various functional systems in the forebrain (e.g., thalamus, hippocampus) is presented in Chapter 8 .
Colored diagrams showing typical areas of arterial supply in each section are provided in this and the preceding and following chapter. We simplified these in two major ways. First, arterial territories are shown as sharply demarcated from each other, when in reality there is significant interdigitation and overlap. Second, perforating arteries arise from all the vessels of the circle of Willis, but we lumped together those from the posterior communicating and posterior cerebral arteries, and those from the anterior communicating and anterior cerebral arteries.