THE BLOOD SUPPLY OF THE HUMAN SPINAL CORD

Abstract

THE problem of the blood supply of the human spinal cord was investigated in considerable detail by various workers at the end of the last century. Adam-kiewicz (1881) studied particularly the course and distribution of both arteries and veins in the white and grey matter of the cord. Eight years later Kadyi (1889) repeated his work, and also studied in great detail the course and distribution of the anterior and posterior spinal arteries, their branches, and their venm commitantes. Kadvi showed that the anterior spinal artery was formed from paired vessels, arising from the vertebral arteries, which passed caudally along the mid-line on the anterior surface of the spinal cord. Either they united almost immediately to form a single vessel or remained as paired arteries with free anastomosis as far as the mid-cervical region of the cord. This single artery then continued its course in the mid-line on the anterior surface of the cord as far as the filum terminale. He showed that the anterior spinal artery was reinforced in its course by several lateral spinal branches which passed to the cord along the anterior or posterior roots. These varied in position and number in different specimens, but in the some 50 cases which he investigated Kadyi noted that most of the lateral spinal branches found entering along the course of many of the anterior spinal roots were very small, and he presumed that they were supplying blood to the root only. However, a few of the lateral spinal vessels were larger, and appeared to carry blood to the anterior spinal artery. Such branches were most common at the level of the 5th or 6th cervical segment and in the lower thoracic or upper lumbar level. They were usually unpaired. Near the termination of the anterior spinal artery at the filum terminale, two large vessels passed laterally and communicated lateral to the posterior spinal roots with the posterior spinal arteries. Kadyi showed that the posterior spinal arteries arose either from the vertebral or from the posterior inferior cerebellar arteries. They then passed caudally and were sometimes joined by one or more lateral spinal branches which reached the cord via the posterior roots at the level of the 4th-7th cervical segments. There was a very free anastomosis between the two posterior arteries across the posterior