THE DEVELOPMENT OF THE VENOUS SINUSES 0^ 

 THE DURA MATER IN THE HUMAN EMBRYO 



GEORGE L. STREETER 



Department of Embryology, Carnegie Institution of Washington 



SEVENTEEN FIGURES 



CONTENTS 



Introduction 145 



Material and methods 146 



Primary vascularization of head 147 



Stages of development of the dural veins 148 



1. Human embryos 4 mm. long 148 



2. Human embryos 14 mm. long 151 



3. Human embryos 18 mm. long 155 



4. Human embryos 20 mm. long 157 



5. Human embryos 50 mm. long 163 



Sinus sagittalis superior 167 



Summary 172 



Literature cited 178 



INTRODUCTION 



In the course of a recent study of the structure and topography 

 of the endolymphatic sac in older human embryos it was found 

 necessary to determine in greater detail than is furnished in the 

 present literature, the relations of the blood vessels of this region, 

 and particularly of the large dural veins that eventually form 

 the dural sinuses of the adult. The abundant material in this 

 laboratory that was found available for this purpose has made it 

 possible to fill out the essential stages in the development of these 

 veins with considerable completeness. The work has been much 

 facilitated by the proximity and advice of Professor Mall who, 

 it will be remembered, was the first to give a comprehensive de- 

 scription of these blood vessels in the human embryo and, in a 

 way, this paper forms a supplement to his original publication. 



145 



THE AMERICAN JOURNAL OF ANATOMY, VOL. 18, NO. 2 

 SEPTEMBER, 1915 



