Category: Heart anatomy

Deep and superficial veins of the legs. As in the upper limb, the veins of the lower limb are divided into deep and superficial, or subcutaneous, which pass independently of the arteries.

Deep veins of the foot, and the legs are double and accompany the same arteries. V. poplitea, composed of all deep veins of the leg, is a single trunk located in the popliteal fossa posterior and somewhat laterally from the artery of the same name. V. femoralis is solitary, initially located laterally from the artery of the same name, then gradually passes to the back surface of the artery, and even higher – to its medial surface and passes in this position under the inguinal ligament in the lacuna vasorum. Tributaries v. femoralis all double.

Of the subcutaneous veins of the lower extremity, two trunks are the largest: v. saphena magna and v. saphena parva. Vena saphena magna, the large saphenous vein, originates on the dorsal surface of the foot from rete venosum dorsale pedis and arcus venosus dorsalis pedis. Having received several tributaries from the foot, it goes upwards along the medial side of the shin and thigh. In the upper third of the thigh, it is bent on the anteromedialal surface and, lying on the wide fascia, goes to hiatus saphenus. In this place v. saphena magna joins the femoral vein, spreading over the lower horn of the crescent edge. Quite often v. saphena magna is double, and both of its trunk can flow separately into the femoral vein. Of the other subcutaneous inflows of the femoral vein, v. epigastrica superficialis, v. circumflexa ilium superficialis, vv. pudendae externae, accompanying the same arteries. They flow in part directly into the femoral vein, part in v. saphena magna at its confluence with hiatus saphenus. V. saphena parva, small saphenous vein, starts on the lateral side of the dorsal surface of the foot, bends around the bottom and back of the lateral ankle and rises further along the back of the tibia; first, it goes along the lateral edge of the Achilles tendon, and further upwards in the middle of the posterior part of the lower leg, respectively, the groove between the heads m. gastrocnemii. Reaching the lower corner of the popliteal fossa, v. saphena parva flows into the popliteal vein. V. saphena parva is connected by branches with v. saphena magna.

1. In the veins, blood flows in most parts of the body (trunk and limbs) against the direction of gravity and therefore slower than in the arteries. Its balance in the heart is achieved by the fact that the venous bed in its mass is much wider than the arterial one. The greater width of the venous bed compared with the arterial is provided by the following anatomical devices: a large caliber of veins, a large number of them, paired accompaniment of arteries, the presence of veins not accompanying the arteries, a large number of anastomoses and greater density of the venous network, the formation of venous plexuses and sinuses, the presence of portal system in the liver. Because of this, venous blood flows to the heart through three large vessels (two hollow veins and the coronary sinus, not to mention the small veins of the heart), while the about one pulmonary trunk.

2. The deep veins accompanying the arteries, i.e., the vein satellites (venae commitantes), in their distribution obey the same laws as the arteries they accompany (see “Regularities in the distribution of arteries”), while most of them accompany the arteries in double number. Paired veins are found mainly where the venous outflow is most difficult, that is, in the extremities, since such a structure has developed even in four-legged animals, in which both pairs of extremities occupy a sheer position and the torso is horizontal.

3. Accordingly, the grouping of the whole body around the nervous system deep veins are located along the nerve tube and nerves. Thus, parallel to the spinal cord is the inferior vena cava, and each segment of the spinal cord corresponds to segmental veins, for example, vv. lumbales and rr. spinales.

4. According to the division of the body into the organs of plant and animal life, the veins are divided into parietal – from the walls of the body cavities and visceral – from their contents, i.e. from the inside.

5. Most of the veins are located on the principle of bilateral symmetry.

6. The veins of the trunk walls retain a segmental structure.

7. Deep veins go along with other parts of the vascular system – arteries and lymphatic vessels, as well as nerves, participating in the formation of neurovascular bundles.

8. Veins also go according to the skeleton. So, along the spine is the inferior vena cava, along the ribs – intercostal veins, along the bones of the limbs – the veins of the same name: shoulder, radial, ulnar, femoral, etc.

9. The veins travel along the shortest distance, that is, approximately in a straight line connecting the place of origin of this vein to its confluence.

10. Superficial veins lying under the skin accompany the skin nerves. A significant part of the superficial veins form subcutaneous venous networks that have no relation to either the nerves or the arteries.

11. Venous plexuses are found mainly on the internal organs, which change their volume, but are located in cavities with unyielding walls, and facilitate the outflow of venous blood with an increase in organs and compression of their walls. This explains the abundance of venous plexuses around the pelvic organs (bladder, uterus, rectum), in the spinal canal, where the pressure of the cerebrospinal fluid constantly fluctuates, and in other similar places.

12. In the cranial cavity, where the slightest obstruction of the venous outflow affects the brain function, there are, in addition to the veins, special devices – the venous sinuses with unyielding walls formed by a hard shell. Therefore, they lie mainly at the site of attachment of durae matris processes to the bones of the skull (sutures of the integumentary bones and sinous bones of the sinuses).

13. Special devices include veins located in the channels diploe – venae diploicae.

The roots of the portal vein anastomose with the roots of the veins belonging to the systems of the upper and lower hollow veins, forming the so-called portocaval anastomoses, which have practical significance. If we compare the abdominal cavity with a cube, then these anastomoses will be located on all its sides, namely:

1. Upstairs, in the esophagus pars abdominalis, between the roots v. gastricae sinistrae, which flows into the portal vein, and vv. esophageae flowing into vv. azygos et hemyazygos and further in v. cava superior.

2. Down in the lower part of the rectum, between v. rectalis superior, flowing through v. mesenteria inferior to the portal vein, and vv. rectales media (tributary v. iliaca interna) et inferior (tributary v. pudenda interna), flowing into v. iliaca interna, and further v. iliaca communis – from system v. cava inferior.

3. In front, in the navel, where their tributaries anastomose vv. paraumbilicales, going in the thickness lig. teres hepatis to portal vein, v. epigastrica superior from system v. cava superior (v. thoracica interna, v. brachiocephalica) and v. epigastrica inferior of system v. cava inferior (v. iliaca externa, v. iliaca communis). Portokavalny and caval caval anastomoses are obtained, having a meaning of a circulating pathway of blood outflow from the portal vein system in the event of obstructions in the liver (cirrhosis). In these cases, the veins around the navel expand and acquire a characteristic appearance (“the head of a jellyfish”).

4. Posteriorly, in the lumbar region, between the roots of the veins of the mesoperitoneal colon (from the portal vein system) and parietal vv. lumbales (from the system v. cava inferior).

5. In addition, there is a caval caval anastomosis between the roots vv on the posterior abdominal wall. lumbales (from the v. cava inferior system) that are associated with the v. lumbalis ascendens, which is the beginning of vv. azygos (right) et hemiazygos (left) (from the system v. cava superior).

6. Cavo-caval anastomosis between vv. lumbales and intervertebral veins, which in the neck are the roots of the superior vena cava.

V. iliaca interna, internal iliac vein, in the form of a short but thick trunk located behind the artery of the same name. The tributaries, from which the internal iliac vein is composed, correspond to the arterial branches of the same name, usually outside the pelvis, these tributaries are in double number, and they are single in the pelvic cavity. In the area of ​​the tributaries of the internal iliac vein, a number of venous plexuses are formed, which anastomose among themselves.

1. Plexus venosus sacralis is composed of the sacral veins – lateral and median.

2. Plexus venosus rectalis – plexus in the walls of the rectum. There are three plexuses: submucosal, subfascial and subcutaneous. The submucosal, or internal, venous plexus, plexus rectalis internus, in the area of ​​the lower ends of the columnae anales represents a series of venous nodules arranged in a ring. The diverting veins of this plexus perforate the muscular layer of the intestine and merge with the veins of the subfascial, or external, plexus, plexus rectalis externus. From the last go v. rectalis superior and vv. rectales mediae, accompanying co-arteries. The first through the inferior mesenteric vein is poured into the portal vein system, the second – into the system of the inferior vena cava through the internal iliac vein. In the area of ​​the external sphincter of the anus, a third plexus is formed — subcutaneous, plexus subcutaneus ani, from which the vv. rectales inferiores flowing into v. pudenda interna.

3. Plexus venosus vesicalis is located in the area of ​​the bottom of the bladder; through vv. vesicales blood is poured from this plexus into the internal iliac vein.

4. Plexus venosus prostaticus is located between the bladder and the pubic symphysis, encompassing the male prostate gland and seminal vesicles. Unpaired v. Merges into plexus venosus prostaticus. dorsalis penis. In a woman, this vein corresponds to v. dorsalis clitoridis.

5. Plexus venosus uterinus and plexus venosus vaginalis women are located in the wide ligaments on the sides of the uterus and further down the side walls of the vagina; blood from them through the ovarian vein (plexus pampiniformis), mainly through v. uterina, enters the internal iliac vein.

 

Vv. iliacae communes, common iliac veins, right and left, merging with each other at the level of the lower edge of the IV lumbar vertebra, form the inferior vena cava. The right common iliac vein is located behind the artery of the same name, the left just below lies behind the artery of the same name, then lies medially from it and passes behind the right common iliac artery to merge with the right common iliac vein to the right of the aorta. Each common iliac vein at the level of the sacroiliac joint in turn is composed of two veins: the internal iliac (v. Iliaca interna) and the external iliac (v. Iliaca externa).

The portal vein collects blood from all unpaired organs of the abdominal cavity, with the exception of the liver: from the entire gastrointestinal tract, where nutrients are absorbed through the portal vein to the liver for neutralization and deposition of glycogen; from the pancreas, where insulin comes from, which regulates sugar metabolism; from the spleen, from which the decay products of blood elements, used in the liver to produce bile, come from. The constructive connection of the portal vein with the gastrointestinal tract and its large glands (liver and pancreas) is due, in addition to the functional connection, and their common development (genetic connection).

V. portae, portal vein, is a thick venous trunk, located in lig. hepatoduodenale along with the hepatic artery and ductus choledochus. Composed v. portae behind the head of the pancreas from the splenic vein and two mesenteric – upper and lower. Heading to the gate of the liver in the above-mentioned bundle of peritoneum, it receives vv along the way. gastricae sinistra et dextra and v. The prepylorica and in the gates of the liver are divided into two branches that go into the liver parenchyma. In the parenchyma of the liver, these branches break up into many small branches that intertwine hepatic lobules (vv. Interlobulares); numerous capillaries penetrate into the lobules and are ultimately formed in vv. centrales (see “Liver”), which are collected in the hepatic veins flowing into the inferior vena cava. Thus, the portal vein system, unlike other veins, is inserted between two networks of capillaries: the first network of capillaries gives rise to venous trunks, of which the portal vein is folded, and the second is located in the liver substance, where the portal vein is divided into its final ramifications.

V. lienalis, the splenic vein, carries blood from the spleen, stomach (through v. Gastroepiploica sinistra and vv. Gastricae breves) and from the pancreas, along its upper edge behind and below the artery of the same name to v. portae.

Vv. mesentericae superior et inferior, superior and inferior mesenteric veins, correspond to the arteries of the same name. V. mesenterica superior on its way takes in the venous branches from the small intestine (vv. Intestinales), cecum, ascending colon and transverse colon (v. Colica dextra and v. Colica media), and, passing behind the head of the pancreas, connects to the inferior mesenteric vein. V. mesenterica inferior begins from the venous plexus of the rectum, plexus venosus rectalis. Heading up from here, it enters the pathway from the sigmoid colon (vv. Sigmoideae), from the descending colon (v. Colica sinistra) and from the left half of the transverse colon. Behind the head of the pancreas, having connected previously with the splenic vein or independently, it merges with the superior mesenteric vein.

V. cava inferior, inferior vena cava, is the thickest venous trunk in the body, lies in the abdominal cavity near the aorta, to the right of it. It is formed at the level of the IV lumbar vertebra from the confluence of two common iliac veins. slightly below the aortic division and immediately to the right of it. The inferior vena cava is directed upwards and somewhat to the right, and the more it moves away from the aorta. The lower section adjoins the medial edge of the right m. psoas, then goes to the front of its surface and at the top lies on the lumbar part of the diaphragm. Then, lying in the sulcus venae cavae on the posterior surface of the liver, the inferior vena cava passes through the foramen venae cavae of the diaphragm into the chest cavity and immediately flows into the right atrium. Tributaries flowing directly into the inferior vena cava correspond to the paired branches of the aorta (except for vv. He paticae). They are divided into the wall veins and internal veins. Parietal veins flowing into the inferior vena cava:
1) vv. lumbales dextrae et sinistrae, four on each side, correspond to the arteries of the same name, take anastomoses from the vertebral plexuses; they are interconnected by longitudinal trunks, vv. lumbales ascendentes;
2) vv. phrenicae inferiores flow into the inferior vena cava where it passes in the groove of the liver.

The veins of the viscera flowing into the inferior vena cava:
1) vv. testiculares in men (vv. ovaricae in women) begin in the area of ​​the testicles and braid like arteries in the form of a plexus (plexus pampiniformis); right v. testicularis flows directly into the inferior vena cava at an acute angle, the left – into the left renal vein at a right angle. This latter circumstance makes it difficult, perhaps, the outflow of blood and causes a more frequent appearance of varicose veins of the left spermatic cord in comparison with the right one (in a woman, v. Ovarica begins at the gate of the ovary);
2) vv. renales, renal veins, go in front of the arteries of the same name, almost completely covering them; the left is longer than the right and passes in front of the aorta;
3) v. suprarenalis dextra infuses into the inferior vena cava immediately above the renal vein; v. suprarenalis sinistra usually does not reach the vena cava and merges into the renal vein in front of the aorta;
4) vv. hepaticae, the hepatic veins, flow into the inferior vena cava where it passes along the posterior surface of the liver; hepatic veins carry blood from the liver, where blood flows through the portal vein and the hepatic artery.

External and internal vertebral plexus. There are four venous vertebral plexuses – two internal and two external. The internal plexuses, plexus venosi vertebrales interni (anterior et posterior) are located in the spinal canal and consist of a series of venous rings, one for each vertebra. In the internal vertebral plexus fall the veins of the spinal cord, as well as vv. basivertebral, leaving the vertebral bodies on their back surface and transporting blood from the spongy substance of the vertebrae. The outer vertebral plexus, plexus venosi vertebrales externi, is divided in turn into two: anterior – on the front surface of the vertebral bodies (developed mainly in the cervical and sacral areas), and posterior, lying on the arches of the vertebrae, covered with deep dorsal and cervical muscles. The blood from the vertebral plexus flows in the trunk through the vv. intervertebrales in vv. intercostales post, and vv. lumbales. In the neck area, outflow occurs mainly in v. vertebralis, which, going along with a. vertebralis, merges into v. brachiocephalica alone or previously connected to v. cervicalis profunda.

Vv. intercostales posteriores, the posterior intercostal veins, are accompanied in the intercostal spaces of the same-named artery by one vein to each artery. About the confluence of the intercostal veins into the unpaired and semi-separ veins mentioned above. The ramus dorsalis (a branch carrying blood from the deep muscles of the back) and ramus spinalis (from the veins of the vertebral plexuses) flow into the posterior ends of the intercostal veins near the spine.

V. thoracica interna, the internal thoracic vein, accompanies the artery of the same name; being double for the most part of the extension, it, however, merges near I rib into one trunk, which flows into v. brachiocephalica of the same side.

The initial section of her, v. epigastrica superior, anastomoses with v. epigastrica inferior (infused in v. iliaca externa), as well as with the subcutaneous veins of the abdomen (vv. subcutaneae abdominis), forming a large mesh of the subcutaneous tissue. From this network, blood flows upward through v. thoracoepigastrica and v. thoracica lateralis in v. axillaris, and downward blood flows through v. epigastrica superficialis and v. circumflexa ilium superficialis in the femoral vein. Thus, the veins in the anterior abdominal wall form a direct connection of the branching areas of the upper and lower hollow veins. In addition, in the navel several venous branches are connected by means of vv. paraumbilicales with portal vein system (see below for more on this).

V. azygos, unpaired vein, and v. hemiazygos, a semi-unpaired vein, is formed in the abdominal cavity from the ascending lumbar veins, vv. lumbales ascendentes connecting the lumbar veins in the longitudinal direction. They go up behind m. psoas major and penetrate the chest cavity between the muscle bundles of the diaphragm stem: v. azygos – together with the right n. splanchnicus, v. hemiazygos – with left n. splanchnicus or sympathetic trunk.

In the chest cavity v. azygos rises along the right lateral side of the spinal column, tightly adhering to the posterior wall of the esophagus. At level IV or V of the vertebra, it departs from the spinal column, and, bending over the root of the right lung, flows into the superior vena cava. In addition to the branches that carry blood from the organs of the mediastinum, the right lower intercostal veins fall into the unpaired vein and, through them, the veins of the vertebral plexuses. Near the place where the unpaired vein is bent over the root of the right lung, it takes in v. intercostalis superior dextra, formed from the confluence of the upper three right intercostal veins.

On the left lateral surface of the vertebral bodies behind the descending thoracic aorta lies v. hemiazygos. It rises only to the VII or VIII thoracic vertebra, then turns to the right and, passing obliquely upwards on the front surface of the spinal column behind the thoracic aorta and ductus thoracicus, flows into the v. azygos. It takes branches from the mediastinum organs and the lower left intercostal veins, as well as the veins of the vertebral plexuses. Upper left intercostal veins infuse into v. hemiazygos accessoria, which goes from top to bottom, settling down, as well as v. hemiazygos, on the left lateral surface of the vertebral bodies, and merges into either v. hemiazygos, either directly in v. azygos, leaning to the right through the front surface of the body VII of the thoracic vertebra.