Spinal cord vascularity. I. Extraspinal sources of spinal cord arteries in man.

The arrangement of extraspinal sources of the spinal cord arterial supply in man is more complicated than previously described, especially with regard to the origin and branching of the aortic segmental arteries. The fact that other arteries in the neck than the vertebral artery, such as the costo-cervical trunk and the ascending cervical artery may contribute to the supply of the cervical cord is confirmed, and also the occurrence of two or more spinal branches from different sources entering the same intervertebral foramen. Frequent occurrence of two or more segmental arteries arising from a common stem and variations in the branching of the subcostal arteries were found; their functional significance on the spinal cord circulation is not known. The fact that no significant anterior root artery was ever seen at the level of the vascular anomaly suggests that the anomaly is of no clinical importance. Nevertheless, obstruction of a common stem entail the risk of spinal cord infarction due to involvement of an important posterior root artery. On the other hand, the spinal cord seems to be fairly well protected against ischaemic injury following limited interference with the extraspinal arteries due to a profuse supply of intra- and extraspinal collaterals.