Cava - top and bottom (venae cavae superior et inferior) - basic venous trunks that collects blood from the body and into the heart. In ontogenesis superior Vena cava is formed from the proximal part of the right front of the cardinal of Vienna and kovarova duct. Education inferior Vena cava is connected with the expansion and extension of vessels due to a reduction in the rear cardinal veins.

the system hollow vein
The system hollow vein:
1 - v. hemiazygos accessoria;
2 - arcus aortae;
3 - cor;
4 - v. cava inf.;
5 - v. suprarenalis sin.;
6 - v. renalis sin.;
7 - v. testicularis sin.;
8 - vv. lumbales;
9 - v. iliaca communis sin.;
10 - v. sacralis mediana;
11 - v. iliaca communis dext.;
12 - v. testicularis dext.;
13 - v. renalis dext.;
14 - v. suprarenalis dext.;
15 - vv. hepaticae;
16 - v. phrenica;
17 - v. azygos;
18 - v. intercostalis sup. dext.;
19 - v. thoracica int.;
20 - v. brachiocephalica dext.;
21 - v. brachiocephalica sin.

Superior Vena cava (Fig) - short thick trunk, located in the thoracic cavity to the right of the ascending aorta; collects blood from the head, neck, chest, and upper extremities; starts from the shoulder-head of the veins on the level of the insertion of the cartilage right I ribs to the breastbone; going down, flows into the right atrium. Before entering the top Vena cava in the pericardium it flows unpaired Vienna (v. azygos). At the top Vena cava directly into only a small veins neighboring regions: Vienna pericardium (vv. pericardiacae), anterior mediastinum (vv.mediastinales ant.) and sometimes right internal thoracic Vienna (v. thoracica int. dext.).
The lower hollow vein is the most powerful venous trunk of the human body; collects blood from the lower extremities, pelvic, abdominal cavity and their walls. The lower hollow vein begins in the abdominal cavity from the merger of the common iliac veins at the level of the IV-V lumbar vertebrae and goes up to the right of the aorta. Lies in the dorsal part of the right furrow liver, through the hole in the diaphragm goes into the chest cavity and into the right atrium. In addition to the common iliac veins in her fall: the average sacral Vienna (v. sacralis mediana), lumbar (vv. lumbales) and diaphragmatic Vienna (vv. phrenicae). To visceral tributaries are: the right Vienna testis (v. testicularis dext.) or ovary (v. ovarica dext.), renal vein (vv. stones), adrenal - vv. suprarenales (left drains into the left renal vein and hepatic (vv. hepaticae). At the confluence into the inferior Vena cava left hepatic vein lies venous link is a remnant of venous duct (ductus venosus), connecting the umbilical vein with lower P. C. in the period of placental circulation.
Top P. C. does not have in its muscle wall of the components except the confluence of the heart, where P. century contain the muscle fibers of atrial myocardium. Lower P. C. has a significant number of muscle cells. Especially well developed continuous layer of longitudinal muscle fibers in her outer shell. In all layers of the wall P. C. there is a major nerve plexus. Myelinated fibers, penetrating into the middle and inner shell veins that form a sensitive end. Efferent innervation P. century is represented by the elements of the autonomic nervous system.
The lower hollow vein can be located to the left of the aorta. In the caudal part of it can be represented by two trunks, which merge in the upper abdomen. Less likely to have a relationship lower P. C. with unpaired. A variety of options confluence P. century in the heart. Often found two upper hollow vein. There are known cases of confluence Vena cava in the left atrium.
Practical importance anastomoses roots of the upper and lower P. century between themselves and with the roots of the portal vein (see) (Kava-kavalenya, Kava-portal and Kava-Kava-portal anastomosis). Note the following basic communications: 1) Vienna cardiac portion of the stomach and esophagus, 2) venous plexus of the rectal wall, 3) anastomoses paraumbilical veins with the roots of the upper and lower epigastric veins (Kava-Kava-portal) and 4) connection ascending lumbar spine, lumbar and veins root mesenteric on the back of the abdominal wall.