For clinical purposes, and particularly in general medicine, the extreme complexity of neuroanatomy must be reduced to its core elements. The following sections cover:

• cranial nerves
• three systems of motor control:
• corticospinal or pyramidal system
• extrapyramidal system
• cerebellum
• motor unit
• reflex arc
• sensory pathways and pain
• control of the bladder and sexual function.

Table 21-4. Causes of the amnestic syndrome

Alcohol (Wernicke-Korsakoff syndrome)

Head injury (severe)

Anoxia

Posterior cerebral artery occlusion (bilateral)

Herpes simplex encephalitis

Chronic sedative and solvent abuse

Bilateral invasive tumours

Arsenic poisoning

Following hypoglycaemia