Infratentorial Vascular Anatomy

Of note, the degree of variability in the anatomy of the posterior circulation (point of origin of different arteries, the size of the PICA-AICA complex, degree of asymmetry, etc.) often leads to nonstandard vascularization of the brainstem and cerebellum.

9.1.3 Infratentorial Artery Pathology

Occlusion syndromes of the basilar artery:

Locked-in syndrome (ventral pontine lesion): quadriplegia, aphonia without loss of conscious, and loss of all voluntary movements except for vertical eye movements and blinking
Top of the basilar syndrome (infarct of the mesencephalon, thalamus, and bilateral parts of the occipital and temporal lobes): somnolence, hallucinations, memory loss, delirium, unilateral or bilateral loss of vertical gaze, nystagmus, oscillatory ocular movements, and visual deficits such as hemianopsia, cortical blindness, and Balint’s syndrome (optic ataxia and simultanagnosia)

9.2 Major Infratentorial Veins

9.2.1 Superficial Veins of the Posterior Cranial Fossa

The superficial cortical veins are well recognized over the external surface of the cerebellum that can be further divided into three surfaces: tentorial, petrous, and the suboccipital (Figs. 9.3, 9.4, 9.5 and 9.6).

9.2.1.1 Cerebellar Tentorial Surface Territory

Superior vermian veins
Paramedian superior cerebellar veins (anterior group is at the level of the tentorial incisure that drain into the tentorial through the precentral vein, and the posterior group drains into the sinus torcular)
Subtentorial veins of the lateral surface: cerebellar hemispheric veins drain into the transverse sinus or in the tentorial sinus.