632 



BLOOD-VESSELS OF THE SPINAL CORD. 



The neuroglia is also abundant on the sides and apex of the posterior horns, where it is called 

 the gelatinous substance of Rolando. 



[Blood- Vessels The spinal cord is partly supplied with blood by arteries from 

 the vertebrals, and partly by branches of the intercostal, lumbar, and sacral 

 arteries,* which reach it through the intervertebral foramina, and pass to the cord 

 along the anterior and posterior roots.] 



[Blood-Vessels. The anterior median (or anterior spinal) (fig. 452) artery gives off 

 branches, which dip into the fissure of the same name, pass to its base, and, after perforating 

 the anterior commissure, divide into two branches, one for each mass of grey matter, and each 

 branch in turn splits into three, which supply part of the anterior, median, and posterior grey 

 matter. The arteries lying in the sulci are called arteri sulci (s) by Adamkiewicz. In the 

 "rev matter, there is usually a special branch to Clarke's column (cl). The vaso-coronary arteries 



include all those arterial branches which proceed 

 from the periphery into the white matter; the 

 finer branches pass only into the white matter, 

 but the larger into the grey substance. The largest 

 branch is the artery of the posterior fissure (Fp), 

 which passes along the posterior septum and reaches 

 almost to the commissure, giving branches in its 

 course. There is a large artery between the column 

 of Goll and the postero-external column, viz., the 



interfunicular artery (if). Arteries enter along the anterior and posterior roots (ra, rp). There 

 are also a median lateral artery (Im), and an anterior and posterior lateral (Ip, la), which 

 enter the lateral column. The general result is that the grey matter is much more vascular 

 than the white, as is shown in fig. 453. Some small vessels come from the pia and send 

 branches to the white matter, and unbranched arteries to the grey matter, where they form 

 a capillary plexus. The blood-vessels are surrounded by perivascular lymph-spaces (His).] 

 [With regard to the blood-vessels supplying the cord as a whole, Moxon has pointed out that, 

 owing to the cord not beiug as long as the vertebral canal, the lower nerves have to run down 

 within the vertebral canal, before they emerge from the appropriate intervertebral foramina. As 

 re-enforcing arteries enter the cord along the course of these nerves, necessarily the branches 

 entering along the course of the lumbar and lower dorsal nerves are long, and this, together with 

 their small size, offers considerable resistance to the blood-stream. Hence, perhaps, the reason 

 why the lower part of the cord is so apt to be affected by various pathological conditions.] 



[Functions of the Spinal Cord. (1) It is a great conducting medium, con- 

 ducting impulses upwards and downwards, and within itself from side to side; 

 (2) the great reflex centre, or rather series of so-called centres; (3) impulses 

 originate within it.] 



