BLOOD VESSELS OF THE BRAIN 



377 



crosses the anterior perforated substance, on its way to its 

 termination in the basal vein. 



The dissector may find it difficult or even impossible to 

 demonstrate the basal vein and its tributaries if the veins are 

 empty, but in a certain number of specimens they are found 

 without difficulty. 



The veins of the supero-lateral surface of the hemisphere 

 are divided into two groups the superior and the inferior 

 cerebral veins. 



A superior cerebral vein' Cut edge of dura mater 



Great anastomotic vein - -:-~ l j,;V~ ' \ Superior cerebral ve 



Superior sagittal 



Transverse sinus 

 Inferior anastomotic vein 



An inferior cerebral .vein 



Superficial middle cerebral vein 

 An inferior cerebral vein 



Sigmoid part of transverse sinus 



FIG. 143. Veins of the supero-lateral surface of the Hemisphere. The 

 dura mater has been removed, but the arachnoid and pia mater are in situ. 



The superior cerebral veins run upwards towards the supero- 

 medial border of the hemisphere where they terminate in the 

 superior sagittal sinus. They vary in number from six to 

 twelve. The more anterior veins enter the sinus at right 

 angles, but the orifices of the more posterior veins are directed 

 obliquely forwards that is, against the blood stream in the 

 sinus (Fig. 143). 



The majority of the inferior cerebral veins converge towards 

 the posterior ramus of the lateral fissure, where they terminate 

 in the superficial middle cerebral vein, which runs forwards, 

 along the fissure, and then, leaving the posterior branch of 



