22 THE MENINGES OF THE BRAIN. 



medial and tentorial surfaces of the occipital lobe and from the 

 superior surface of the cerebellum (Cunningham). 



Small nameless internal veins issue from all parts of the exterior 

 surface of the cerebrum and form the external veins. 



The External Veins of the Cerebrum. The external cerebral 

 veins (vena cerebri externa) are numerous and of large size. They 

 ramify in the pia mater and in the subarachnoid space. They 

 empty into the dural sinuses, as a rule, against the current in the 

 sinuses, and they form two principal groups: The superior 



Fig. 1 1 . Middle cerebral artery and branches. (Gordinier after Quain and Char cot.) 



CENT. Antero-lateral group of ganglionic arteries. I. Inferior external frontal artery. 

 2. Ascending frontal artery. 3. Ascending parietal artery. 4. Parieto-temporal artery. 



cerebral and the inferior cerebral, and a very small group, on 

 the medial cerebral surface, called the medial cerebral veins. 



The superior cerebral veins (vena cerebri superiores), twelve 

 or more in number, carry away the blood from the superior surface 

 of the hemisphere. They run obliquely upward and forward 

 into the superior sagittal sinus. Just before emptying into the 

 sinus they receive most of the medial veins. 



The Medial Cerebral Veins. (Vena cerebri mediales}. They 

 drain the marginal part of the medial surface of the hemisphere. 



