ANGEIOLOGY. 101 
posterior saphena vein, with numerous branches: ascending obliquely 
inwards, it passes through the opening in the tendon of the triceps to 
become the 
FrmMorAL VEIN, which is joined in the groin by the profunda and saphena 
veins to form the 
Exrernan Intac Vern. This extends from Poupart’s ligament to the 
ilio-sacral symphysis, where it meets the internal iliac to form the common 
iliac. It also receives the trunk of the epigastric veins, and of the two 
circumflex ili. 
THE INTERNAL In1Ac VEIN accompanies the artery in its inner side ; it is 
formed by the union of several veins corresponding to the branches of the 
internal iliac artery, viz. obturator, pudic, sciatic, gluteal, &e. 
THE Common IxitAc VEINS are formed by the union of the two internal 
and external, opposite each ilio-sacral symphysis. Ascending, they meet at 
an acute angle, opposite the fourth intervertebral ligament to the right side 
of and a kttle below the division of the aorta. Their union constitutes the 
inferior or ascending vena cava. 
THE INFERIOR VENA Cava, thus constituted, ascends along the right side 
of the aorta, passes through the diaphragm, and opens into the lower and 
back part of the right auricle. It receives the lumbar, spermatic, renal or 
emulgent, capsular or supra-renal, inferior phrenic, and the hepatic veins. 
The inferior cava is larger than the superior ; it returns the blood from all 
parts of the body below the diaphragm, collecting that of the portal system 
through the medium of the hepatic veins. | 
Pl. 136, jig. 1”, hepatic vein; ”, internal spermatic; ”, supra-renal ; 
* renal veins; *, connecting branch between the renal and common iliac 
veins; **, lumbar veins; **, common iliac; *, femoral; *’, hypogastric ; 
*8,29,° lateral and middle sacral veins. 
Pi. 184, fig. 7’, internal saphena vein; *, exterior epigastric; *, an acces- 
sory, and *, a principal branch of the internal saphena. fg. 8’, course of 
the internal saphena on the inside of the leg; *, its commencement on the 
back of the foot. J/g. 9, plexus on the back of the foot. Fg. 10’, exter- 
nal saphena; *, internal do. 
20 
4, THE PoRTAL SYSTEM. 
The portal system constitutes a peculiar vascular arrangement in the liver 
for the purification of the blood and the secretion of the bile. The portal 
vein, or vena porta, although it arises in the abdomen as a vein, and serves 
the same office, yet terminates in the liver like an artery, and has a secreting 
function; it returns the blood from all the chylopoietic viscera, to be dis- 
tributed through the liver, and in the latter organ it receives the venous 
blood from the termination of the hepatic artery. It is four or five inches 
long, and is formed by the confluence of the splenic and mesenteric veins 
behind the pancreas. Ascending obliquely, it receives branches from the 
pancreas, duodenum, stomach, and gall-bladder, and enters the left extremity 
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