38 



DEVELOPMENTAL ALTERATIONS IN THE VASCULAR SYSTEM. 



REFERENCES CITED. 



Elze, C. 1907. Beschreibung eines menschlichen Em- 

 bryo von za. 7 mm. grosster Lange. Anat. 

 Hefte, No. 106, vol. 35, Ahth. 1. 



Evans, H. M. 1909. On the development of the aortse, 

 cardinal and umbilical veins, and other blood- 

 vessels of vertebrate embryos from capillaries. 

 .\nat. Rec, vol. 3. 



. 1912. The development of the vascular system. 



Keibel-Mall Manual of Human Embrj'ology, vol. 2. 



Grosser, O. 1907. Die Elemente des Kopfvenensystem 

 der Wirbcltiere. Verh. .\nat. Gesell., Anat. Am., 

 Bd. .30, Erg.inz. Hft. 



und E. Brezix.\. 189.5. Uel)er die Entwicklung 



der Venen des Kopfes und Halses bei Reptilien. 

 Morph. Jahrbuch, Bd. 23. 



His, \V. 1904. Die Entwickelung des menschlichen 

 Gehirns. Leipzig. 



HocHSTETTER, F. 1916. Ucbor die V.askularisation der 

 Haut des .Schadeldaches menschiicher Embr>'onen. 

 K. Akad. d. Wiss. Wien, Math.-Naturwis.s. Kl., 

 Bd. 93. 



Ingalls. N. W. 1907. Beschreibung eines menschlichen 

 Embryo von 4.9 mm. Archiv. f. mikr. Anat., 

 vol. 70. 



Mall, F. P. 1905. On the development of the blood- 

 vessels of the brain in the human embryo. Am. 

 Jour. Anat., vol. 4. 



Markowski, J. 1911. Ueber die Entwicklung der Sinus 

 durae matris und der Hirnvenen bei menschlichen 

 Embryonen. Bull. d. I'Acad. d. Sci. de Cracovie. 

 CI. d. Sci. math. -Nat., Serie B. 



Sabin, F. R. 1915. On the fate of the post-cardinal veins and 

 their relation to the development of the vena cava 

 and azygos in the embryo pig. Contributions to 

 Embryology, Carnegie Inst. Wash. Pub. No. 223. 



. 1917a. Origin and development of the primitive 



vessels of the chick and of the pig. Contributions 

 to Embrj'ology. Carnegie Inst. Wash. Pub. No. 226. 



. 19176. Preliminary note on the differentiation of 



angioblasts and the method by which they produce 

 blood-vessels, blood-plasma, and red blood-cells 

 as seen in the living chick. Anat. Rec, vol. 13. 



Salzer, H. 1895. Ueber die Entwicklung der Kopfvenen 

 des Meerschweinchens. Morph. Jahrbuch, Bd. 23. 



Shindo, T. 1915. Ueber die Bedeutung des Sinus caver- 

 nosus der Siiuger mit vergleichend anatomischer 

 Beriicksichtigung anderer Kopfvenen. Anat. 

 Hefte, Abth. 1, Heft 157, Bd. 52. 



EXPLANATION OF PLATES. 



Plate 1. 



Simplified profile drawings of the dural veins, showing the manner in which they adapt themselves to the growth and change 

 in form of the brain in human embrjos from 4 mm. to birth. 



Fig. 13, embryo No. 588, 4 mm.; fig. 14, embryo No. 940, 14 mm.; fig. 15. embrj-o No. 144. 18 mm.; fig. 16, 

 embryo No. 460, 21 mm.; fig. 17. cmbrj'o No. 632, 24 mm.; fig. 18, embrjo No. 199. 35 mm.; fig. 19, 

 embryo No. 96, 50 mm. CR length: fig. 20, embryo No. 234a, 80 mm. CR length; fig. 21, adult. 



Plate 2. 



Right and left profile views of a wax-plate reconstruction of the main arteries and veins in a human embryo 4 mm. long 

 (Carnegie Collection, No. 588). Enlarged about 40 diameters. 



This stage illustrates the character of the first type of the circulation of the head and its relation to the other 

 blood-vessels of the body. The primary head-vein and its tributaries which form the main drainage-channels of the 

 head aie shown in blue. These communicate by anastomosing loops with the capillarj' plexus everywhere investing the 

 brain-wall, only patches of which are shown in the model. The capillary plexus of the brain-wall is fed by aiterial 

 feeders, the stumps of which, as shown in the model, arise from the aortic system. The trunk that persists as the 

 internal carotid artery is already quite definite. 



Plate 3. 



Right and left profile views of a wax-plate reconstruction of the blood-vessels of the brain in a human embryo 11.5 mm. long 

 (Carnegie Collection, No. 544). Enlarged about 14 diameters. The primary head-vein stiil constitutes the main 

 drainage-channel of the head. The manner in which its tributaries tap the deep capillary sheet investing the brain 

 is indicated over a small area of the cerebral hemisphere. A capillary mesh of that kind invests the entire central 

 nervous system, but is not shown in the model. 



Plate 4. 



Left lateral view of a wax-plate reconstruction of the larger blood-vessels of the brain in a human embryo 21 mm. long (Car- 

 negie Collection, No. 460). Enlarged 16.4 diameters. Instead of the head being drained by the primary head-vein, 

 this is now accomplished by a more dorsally situated channel that has formed through the meshes of the middle and 

 posterior dural plexuses to become the transverse sinus. (Compare with text-figure 3, which shows a left profile of 

 the same specimen.) All that is left of the primary head-vein is that portion which is to become the cavernous sinus. 

 In this model the right cerebral hemisphere has been dissected so as to expose the chorioidal body with its arterial 

 feeder and the straight sinus draining it. The plexiform character of the superior sagittal sinus and of the caudal end 

 of the straight sinus is indicative of their transitory condition. 



Plate 5. 



Left profile view of a wax-plate reconstruction of the blood-vessels of the brain in a human embryo 43 mm, long (Carnegie 

 Collection. No. 886). Enlarged 8 diameters. The vascular architecture is at this stage beginning to approximate 

 the adult condition, although the whole tentorial region retains its embiyonic character, d\ie to which the marked 

 subsequent migr.ation of the transverse sinus is possible. It will be noted that the siguioid portion of the sinus is 

 fairly well established. 



