THE VASCULAR SUPPLY OF THE PINEAL ORGAN 4II 



its terminal part and the openings into it of these two vessels, any resulting 

 congestion of the choroidal veins which might result from an obstruction 

 at the commencement of the vein would be relieved by the anastomoses 

 between the tributaries of the basal veins and the choroidal veins in the 

 inferior horns of the lateral ventricles. For detailed description of the 



Fig. 274. — Diagram showing the Principal Tributaries and Relations of 

 the Great Vein of Galen, and the position occupied by a Pineal Tumour. 



anatomy of these veins in connection with the production of hydro- 

 cephalus the reader should consult articles by Dandy and Blackfan 

 (1914), Stopford (1926, 1928), and Bedford (1934). 



Since no lymphatic vessels are present in the central nervous system 

 of which the pineal organ is a part, it is probable that secretory or waste 

 products contained in the tissue-fluids of the pineal body would, like the 

 cerebrospinal fluid, be absorbed directly into the venous system through 

 perivascular channels which are in communication with the tissue spaces. 



