460 Veins of the Trunk. 



Y. cava inferior (see also Fig. 633) arises by the union of the vv. ihacae communes 

 in front of the intervertebral disk between the i^^ and 5^^ limibar vertebra behind the first 

 ])ortion of the a. iliaca communis dextra somewhat to the right of the median plane. From 

 there on, it ascends at first in front of the bodies of the lumbar vertebrae and in front of the 

 origins of the right m. psoas major, then in front of the a. renalis dextra and in front of the 

 right crura diaphragmatis and at the same time somewhat to the right and forward, goes through 

 the foramen venae cavae of the diaphragm and, cuiwed somewhat forward, opens into the right 

 atrium of the heart. In its course it lies on the right side of the aorta abdorainalis and is 

 covered in front by the peritonaeum, by the pars inferior duodeni and by the caput pancreatis; 

 above, it is embedded in the fossa venae. cavae of the liver and firaily fused with it, so that 

 only its posterior wall lies partly fi-ee (see Fig. 581). It is devoid of valves. Its branches are 

 divisible into radices parietales (from the walls of tM jieritoneal cavity) and radices 

 viscerales (from the abdominal viscera)^ 



A. Radices parietales: ^ - . . - ,.' 



1. Y. phreiiica inferior, paired, corresponds to the a. phrenica inferior and opens at 

 the foramen venae cavae. 



2. Yv. liimbales (see also Figs. 495 and 500), on eg,ch side 4 5, run close to and 

 over the aa. lumbales, correspond to tlie' yv. intercostales (see p. 455) and receive tributaries 

 from the muscles and from the skin of the back, from tlie plexuses of the spine and from the 

 abdominal muscles. They possess (insufficient) valves, run medianward upon the lateral and 

 anterior surface of the bodies of the yertebrae (those of the left side behind the aorta) and 

 open into the posterior wall of the v. cava. The vv. lumbales are united on each side with 

 one another by means of longitudinal anastomoses which are situated behind the ra. psoas 

 major in front of the roots of the procc. transversi. The sum of these anastomoses forms on 

 each side a vessel running vertically, the v. lumbalis ascendens, - which is connected below with 

 the V. iliolumbalis and frequently with the v. iliaca communis, above however is continued on 

 the right side directly into the v. azygos, on the left side into-. the v. hemiazygos (see p. 456); 

 each anastomoses usually with the a: renalis of the same side. 



B. Radices viscerales: 



1. Yv. hepaticae (see also Fig. 580), 2 3 large trunks, collect the blood which is led to 

 the capillary system of the liver through the a. hepatica propria and v. portae; they leave the 

 liver in the uppermost part of the fossa venae cavae and open into the v. cava just below the dia- 

 phragm. The right v. hepatica, largest, carries the blood from the right lobe of the liver, the 

 middle, smallest vein fi-om the lobi caudatus [Spigeli] and quadratus, the left from the left lobe I 

 of the liver. Several small vv. hepaticae open in the fossa venae cavae, below the large ones, 

 directly into the v. cava inferior. Valves are only rarely present at the mouths of the large veins. 



2. Y. renalis. (renal vein) (see also Fig. 633),- paired, arises by the fusion of ft-om three 

 to five branches near the hilus renalis , runs medianward and at the same time somewhat 

 upward at the level of the 2"'! lumbar vertebra in front of the a. renalis and opens into the 

 lateral wall of the v. cava. The left v.. renalis is -somewhat "the -larger and longer; it lies 

 usually in front of the aorta just beneath the origin of the a. mesenterica superior. It re- 

 ceives tributaries ft-om the capsula adiposa of the kidney and from the ureter; the left v. renalis 

 receives also usually the v. spermatica sinistra. In addition the left vein anastomoses very 

 frequently with the v. hemiazygos and the v. lumbtilis ascendens , the right with the latter 

 only. The vv. renales rarely possess valves at their mouths.* 



3. Y. suprarenalis (suprarenal vein) (see also Fig. 639), paired, comes from the anterior 

 surface of the adrenal and opens on the right side usually into the v. cava, on the left side 

 into the v. renalis. It is devoid of valves. 



4. Y. spermatica (spermatic vein) (see also Figs. 500, 502 and 503), paired, accompanies 

 the a. spermatica interna directly and is separated from it only at its termination. It consists 

 of from 2 to 3 anastomosing vessels which surround the artery like a plexus, receive branches 

 from the ureter, from the peritonaeum and from the capsula adiposa of the kidney and imite 

 finally to form a single trunk. The right vein opens obliquely into the anterior wall of the 

 V. cava and there possesses efficiinit valves, the left goes almost at a right angle into the in- 

 ferior wall of tlie V. renalis sinistra. The beginning of the vein is different in the two sexes. 



In the male, v. testicularis, .it begins with numerous branches at the posterior margin 

 of the testicle and epididymis (see also Fig. 650), forms a close plexus (plexus pmnpiniformis) 

 around the artery inside the funiculus spermaticus and extends, with this, through the canalis 

 inguinalis. Outside the inguinal canal it usually possesses (insufficient) valves. 



In the female, v. ovarica, it arises partly from numerous vessels, which leave the ovary 

 at its hUus, jiartly from broad anastomoses with the upper ends of the vv. uterinae ; in addition 

 it receives some branches from tlie lig. teres uteri and from the tuba uterina. All these 

 branches, anastomosing, form a close plexus (plexus immpiniforinis) around the artery, mside 

 the lig. suspensorium ovarii and are devoid of valves. 



