274 



THE DEVELOPMENT OF THE VASCULAR SYSTEM 



Middle cerebral win 



Posterior cerebral vein 



Sinus cavernosus 

 Anterior cerebral vein 





N. hypoglossus 

 V. capitis laleralis 



FIG. 283. Veins of the head of a 9 mm. human embryo (after Mall). X 9. 

 A C 



Auditory vesicle 



I 



Vena capitis medialis 

 Trigeminal nerve l 

 Ophthalmic vein 



Superior sagit- 

 tal sinus 



Confluence of the sinuses 



. ... . , Superior 

 Primitive jugular sagittal 

 vein s i mis 



Middle cerebral vein 



Posterior cerebral 



vein 



tis lateralis 



Anterior cerebral vein 



Ophthalmic vein 

 Trigeminal nerve 



Vena capitis 

 lateralis 



Auditory vesicle 



Anterior cerebral vein 



Confluence of the /Middle cerebral vein 



sinuses \ / \ A uditory vesicle 



Superior 



sagittal 



sinus 



Trigeminal nerve 



Ophthalmic vein Vena capitis 

 lateralis 



D 



Inferior sagittal sinus Straight sinus 



Great cerebral 

 Superior sagittal 



Posterior 



cerebral 



vein 



Jugular Anterior cere- 

 vein bral vein 

 Sphenopari- 

 etal sinus 



Superior 

 petrosal 

 sinus 

 Trans- 

 verse 

 sinus 



Auditory vesicle 



Ophthalmic vein \ Inf. petrosal sinus 

 Trigeminal nerve 



FIG. 284. Four diagrams showing the development of the veins of the head (after Mall). 

 A, At four weeks; B, at five weeks; C, at the beginning of the third month; D, from an older fetus. 



he snu.ses 



