14 



Devolopnieiit of Blood- Vessels of Human Brain 



external Jugular vein is formed, as shown by Salzer. The vena capatis 

 lateralis is fully developed during the fifth week, as is best shown in 

 Fig. 13. In this embryo it is irregular in shape, ending in a lakelet 

 behind, a condition which may also be due to the way the blood accu- 

 mulated in this vein just before the death of the embryo. In Fig. 10, 

 which is from an embryo in which these veins were gorged with blood, 

 the lakelet is not present. Soon the vena capatis disappears, and veins 

 more dorsal wards carry blood from the brain, as shown in Fig, 11. 



Fig. 14. 

 Fig. 14. Diagram of the veins of the head of an embryo four weelis old. ACV, anterior 

 cardinal vein; VCL, vena capatis lateralis; SLS, superior sagittal sinus; 4 F, auditory 

 vesicle ; V, fifth nerve ; i, eye. 



VCP 



Fig. 15. 

 Fig. 15. Diagram of the veins of the head during the fifth week. VCP, vena cerebralis 

 posterior; VCM, vena cerebralis media; VCA, vena cerebralis anterior; TH, torcular 

 Herophili ; OF, ophthalmic veins ; VJ, jugular vein. 



When the vena capatis is well developed it sends from its two extremi- 

 ties two main veins to encircle the brain and to collect its blood. The 

 first of them, the vena cerebralis media, arises at the point of juncture 

 between the vena capatis lateralis and the cavernous sinus and extends 

 between the fifth and seventh nerves towards the region of the cerebellum. 



