Spinal cord venous drainage

Functional disturbances within the spinal cord are caused by the venous congestion due to arteriali-zation and elevated pressure of the medullary veins (Aminoff et al. 1974). In addition, venous outlets are insufficient and thus reinforcing impairment of the venous circulation and chronic spinal hypoxia. In particular, Merland and coworkers (1980) introduced the concept of blocked venous drainage into the epidural space. 

The posterior cerebral artery supplies the occipital lobe and portions of the medial and inferior temporal lobe. The arterial supply of the spinal cord is derived from the vertebral arteries and the radicular arteries. The brain is supplied by the internal carotid arteries (the anterior circulation) and the vertebral arteries, which join at the pon tomedullary junction to form the basilar artery (collectively termed the posterior circulation). The brainstem is supplied by the posterior system. The medulla receives blood from branches of the vertebral arteries as well as from the spinal arteries and the posterior inferior cerebellar artery (PICA). The pons is supplied by paramedian and short circumferential branches of the basilar artery. Two major long circumferential branches are the anterior inferior cerebellar artery (AICA) and the superior cerebellar artery. The midbrain receives its arterial supply primarily from the posterior cerebral artery as well as from the basilar artery. The venous drainage of the spinal cord drains directly to the systemic circulation. By contrast, veins draining the cerebral hemispheres and brain stem drain into the dural sinuses. Cerebrospinal fluid also drains into the dural sinuses through unidirectional valves termed arachnoid villi. 

Symptoms may arise from compression of the medulla, the spinal cord, nerve roots, afferent vasculative and/or venous drainage. In most cases a combination of these is seen. Common to all of these factors is that they are located anterior to the cord even when symptoms they elicit suggest lateral or dorsal pathology. 

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