This chapter provides some of the key neuroanatomical considerations that may impact on neuroanaesthesia and neurointensive care. There are multiple factors that require consideration when planning an operative approach. A good grasp of neuroanatomy is essential both in the operating room as well as the pre-operative stage in terms of assessing the relative likelihood of pathology causing the clinical symptoms and signs. The chapter discusses the functional significance of the cerebral and cerebellar hemispheres. The frontal lobes are the cerebral hemispheres anterior to the Rolandic fissure. The cerebral circulation is made up of two components. The anterior circulation is fed by the internal carotid arteries, while the posterior circulation derives from the vertebral arteries. Flow of cerebrospinal fluid (CSF) across the ventricular wall into the brain extracellular space is not an important mechanism under physiological conditions.