The microvasculature of the spinal cord in the human adult

Abstract

The microvasculature of the human spinal cord have been studied with scanning electron microscopy (SEM) on the corrosion casts of blood vessels, and light microscopy on the transparent after intra‐arterial injection of Indian ink and vascular staining specimens.On the surface of the cord, the density of the pial venous plexus was higher than the pial arterial plexus. The anterior spinal artery and vein gave off central arteries and veins, which ran posteriorly within the anterior median fissure. The number of the central arteries and veins per centimeter in length is highest in the lumbosacral cord, followed by the cervical and then the thoracic cord. In this study, the central arteries and veins were classified into types; type 1 dominated the arterial system and type 2 the venous system. The central arteries and veins sent long branches both rostrally and caudally along the axis of spinal cord. The order of their length was as follows: thoracic, cervical, lumbar and sacral cord. These blood vessels overlapped each other. The peripheral arteries terminated in the periphery of the gray matter while the peripheral veins originated within the different depth of the gray matter. The posterior spinal artery supplied the posterior horn and the substantia gelatinosa. The posteromedial veins arose in the deep posterior horns and posterior funiculus, and were occasionally connected with the anterior spinal vein within the cord. Overlapped zone which was supplied by both the central and peripheral vascular system was seen within the cord, and its extent was variable at different levels. The overlapped zone of the venous supply was broader than the arterial one. The peripheral veins appeared to drain blood not only from the white matter but also from the gray matter. The distribution of the capillary networks in the gray matter was slightly denser and showed more horizontal arrangement in the lumbosacral cord, and more sparse and longitudinal in the cervicothoracic cord. The distribution of the capillary networks in the white matter was parallel to nerve fibers which run longitudinal in the whole cord.Based on the result of present study, it was considered that the circulatory disturbances are prone to occur in the thoracic cord, and the circulatory block in the arterial system of the cord tends to cause a lesion in the gray matter, whereas the circulatory disturbances in the venous system tends to cause a lesion in the white matter.