256 Veins ofthejuperhr Extremity. [Book IX. 



ihall now proceed to enumerate, in a curfory manner, 

 the branches by which thefe trunks are fupplied. 



In treating of the brain, I iriall endeavour to defcribe 

 more fully the triangular canals, called fmufes, fituated 

 in the dura mater, and which perform the office of 

 veins. The vena cava fuperior is formed in the follow- 

 ing manner. The blood, which is fent to the inter- 

 nal parts of the head, after pafTing through other veins 

 and fmufes is received by the two lateral fmufes j thefe 

 terminate in the internal jugular veins, which corre- 

 fpond with the internal carotid artery, and terminate in 

 the fubclavian vein. The external jugular vein, which 

 correfponds with the external carotid artery, receives 

 the blood from the external parts of the head, and alfo 

 terminates in the fubclavian vein. This vein alfo re- 

 ceives the contents of the vertebral vein, which cor- 

 relponds with the artery of the fame name. 



The veins of the fuperior extremities run in two 

 fets; fome of them lie immediately under the fkin, 

 others are deeply feated, and accompany the arteries. 

 The vena bafilica is formed by a number of branches > 

 it, proceeds immediately under the Ikin, along the 

 courfe of the ulna, to the internal condyle of the os 

 humeri. It afterwards runs up along the infide of the 

 arm, communicating freely both with the deep and 

 fuperficial veins. The vena cephalica receives, at the 

 extremity of the radius, branches which correfpond with 

 thofe of the radial artery. The trunk runs along the 

 radius, between the mufcles and integuments, com- 

 municating with all the neighbouring veins j having 

 pafled the fold of the arm, it afcends near the outer 

 edge of the external portion of the biceps, ftill com- 

 municating with the other veins, and pafilng between 

 the large pecftoral and deltoid mufcles, terminates, as 

 well as die bafilica, in the trunk of the axillary vein. 



Th* 



