The third ventricle in hydrocephalus due to basal cistern block.

Abstract

One hundred and two cases of hydrocephalus due to basal cistern block were studied by ventriculography and encephalography. The third ventricle shows anterior displacement and there are varying degrees of impression upon the infundibular recess produced by a dilated inter-peduncular cistern. The block in the basal cisterns may occur at any level between the exit foramina of the fourth ventricle and the level of the tentorium. Loculation of cerebrospinal fluid in a basal cistern is seen with moderate frequency. —The cerebrospinal fluid protein levels in basal cistern block, which were usually moderately or markedly elevated, did not distinguish these cases from those with aqueduct stenosis. Nearly 20 per cent of the basal cistern block cases also had aqueduct stenosis. — The aetiology of the block in the basal cisterns is usually either haemorrhage (due to anoxia or trauma) or infection. Either of these causes the formation of obstructive adhesions in the subarachnoid space.