Neuroanatomy and Physiology for the Neuroscience Nurse
Localize by lobe, vessel, and system
Most neuroanatomy items test whether you can link a lesion to a deficit. Frontal lobe: executive function, expressive language (Broca, dominant hemisphere), voluntary movement (precentral gyrus), and conjugate gaze deviation toward a destructive lesion. Parietal: contralateral sensory integration and spatial attention - nondominant lesions cause neglect. Temporal: hearing, memory (hippocampus), receptive language (Wernicke, dominant). Occipital: primary vision; a PCA infarct produces a contralateral homonymous hemianopia, often with macular sparing.
Deep structures and posterior fossa
The basal ganglia modulate movement (Parkinson, Huntington); the thalamus is the sensory relay; the internal capsule carries densely packed motor tracts, so a small lacunar infarct there causes a large deficit. Cerebellar lesions cause ipsilateral ataxia, dysmetria, and nystagmus. The brainstem houses cranial nerve nuclei III–XII plus respiratory and cardiac centers - small lesions, large consequences.
Vascular territory
The anterior circulation (carotid to MCA/ACA) supplies most cortex; the MCA is the most commonly occluded vessel and yields contralateral face and arm worse than leg, aphasia if dominant, neglect if nondominant. The posterior circulation (vertebrobasilar to PCA) supplies brainstem, cerebellum, and occipital cortex.
CSF and the closed box
CSF is made mainly by choroid plexus (~500–600 mL/day) with a total volume near 150 mL, flowing lateral to third to fourth ventricle to subarachnoid space to arachnoid granulations. Brain (~80%), blood (~10%), and CSF (~10%) fill a fixed skull; an expanding mass must displace one of them or ICP rises (Monro-Kellie).
Traps: attributing a hemianopia to a frontal lesion, mixing up ipsilateral versus contralateral cerebellar signs, and calling a posterior circulation stroke a 'lacunar' event.
Rule of thumb: localize first (where is the lesion?), then predict the deficit, then match it to the vessel - questions are usually written in that order.