fig 6.

Greitz and Greitz's theory on the pathogenesis of hydrocephalus.

A, Normal systole. The systolic pulse wave causes a large expansion of the arteries with a concomitant and successful dampening of the arterial pressure. The pressure is immediately transmitted to the entire subarachnoid space. After some delay, a small pressure wave is transmitted to the brain via the intracerebral arteries. This causes a slight brain expansion and a transcerebral mantle pressure gradient of normal magnitude, which keeps the ventricles patent and of normal size.

B, Hydrocephalus systole. The arterial pulsations are restricted, so little or no dampening of the arterial pressure occurs. The undamped pulse pressure is therefore transmitted into the brain, giving rise to an increased transcerebral mantle pressure gradient. Ventricular dilatation results. Reproduced from (19) with permission from Lippincott Williams & Wilkins.