Heart and Circulation Blood is a complex fluid that carries oxygen and nutrients to muscles and other organs and removes waste produced in them. Blood flows through the body closed system from blood vessels. The heart is pumping

The term collateral circulation implies the flow of blood through the lateral branches into the peripheral parts of the limbs after blocking the lumen of the main (main) trunk. Collateral blood flow is an important functional mechanism of the body, due to the flexibility of blood vessels and is responsible for uninterrupted blood supply to tissues and organs, helping to survive myocardial infarction.

The role of collateral circulation

Essentially, collateral circulation is a roundabout lateral blood flow that occurs through the lateral vessels. Under physiological conditions, it occurs when normal blood flow is obstructed, or in pathological conditions- wounds, blockage, ligation of blood vessels during surgery.

The largest ones, taking on the role of a switched off artery immediately after blockage, are called anatomical or preceding collaterals.

Groups and types

Depending on the localization of intervascular anastomoses, previous collaterals are divided into the following groups:

1. Intrasystemic - short paths of roundabout circulation, that is, collaterals that connect the vessels of the large arteries.
2. Intersystem - roundabout or long paths that connect the basins of different vessels with each other.

Collateral circulation is divided into types:

1. Intraorgan connections - intervascular connections inside separate body, between the vessels of the muscles and the walls of the hollow organs.
2. Extraorgan connections are connections between the branches of the arteries that supply a particular organ or part of the body, as well as between large veins.

For strength collateral blood supply the following factors influence: the angle of departure from the main trunk; diameter of arterial branches; functional state of blood vessels; anatomical features of the lateral anterior branch; the number of lateral branches and the type of their branching. An important point for volumetric blood flow is the state in which the collaterals are: relaxed or spasmodic. The functional potential of collaterals is determined by regional peripheral resistance and general regional hemodynamics.

Anatomical development of collaterals

Collaterals can exist in both normal conditions, and develop again during the formation of anastomoses. Thus, a disruption of the normal blood supply caused by some obstruction in the path of blood flow in a vessel involves already existing blood bypasses, and after that new collaterals begin to develop. This leads to the fact that the blood successfully bypasses the areas in which the patency of the vessels is impaired and the impaired blood circulation is restored.

Collaterals can be divided into the following groups:

• sufficiently developed, characterized by wide development, the diameter of their vessels is the same as the diameter of the main artery. Even complete closure of the main artery has little effect on the blood circulation of such an area, since anastomoses fully replace the decrease in blood flow;
• insufficiently developed ones are located in organs where intraorgan arteries interact little with each other. They are usually called ring ones. The diameter of their vessels is much smaller than the diameter of the main artery.
• relatively developed ones partially compensate for impaired blood circulation in the ischemic area.

Diagnostics

To diagnose collateral circulation, you first need to take into account the rate of metabolic processes in the extremities. Knowing this indicator and by intelligently influencing it using physical, pharmacological and surgical methods, it is possible to maintain the viability of an organ or limb and stimulate the development of newly formed blood flow pathways. To do this, it is necessary to reduce the tissue consumption of oxygen and nutrients supplied by the blood, or to activate collateral circulation.

Collateral circulation is an important functional adaptation of the body, associated with the great plasticity of blood vessels and ensuring uninterrupted blood supply to organs and tissues. A deep study of it, which is important practical significance, is associated with the name of V. N. Tonkov and his school (R. A. Bardina, B. A. Dolgo-Saburov, V. V. Ginzburg, V. N. Kolesnikov, V. P. Kurkovsky, V. P. Kuntsevich , I. D. Lev, F. V. Sudzilovsky, S. I. Shchelkunov, M. V. Shepelev, etc.).

Collateral circulation refers to the lateral roundabout flow of blood through the lateral vessels. It occurs under physiological conditions during temporary difficulties in blood flow (for example, when blood vessels are compressed in places of movement, in joints). It can also occur in pathological conditions - during blockage, wounds, ligation of blood vessels during operations, etc.

Under physiological conditions, roundabout blood flow occurs through lateral anastomoses running parallel to the main ones. These lateral vessels are called collaterals (for example, a. collateralis ulnaris, etc.), hence the name of the blood flow - roundabout, or collateral, circulation.

When there is difficulty in blood flow through the main vessels, caused by their blockage, damage or ligation during operations, blood rushes through anastomoses into the nearest lateral vessels, which expand and become tortuous, the vascular wall is rebuilt due to changes in the muscular layer and elastic frame, and they are gradually transformed into collaterals different structure than normal (R. A. Bardina).

Thus, collaterals exist under normal conditions, and can develop again in the presence of anastomoses. Consequently, in the event of a disorder of normal blood circulation caused by an obstacle to the blood flow in a given vessel, the existing bypass blood pathways and collaterals are first activated, and then new ones develop. As a result, impaired blood circulation is restored. In this process plays an important role nervous system(R. A. Bardina, N. I. Zotova, V. V. Kolesnikov, I. D. Lev, M. G. Prives, etc.).

From the above it follows the need to clearly define the difference between anastomoses and collaterals.

Anastomosis(anastomoo, Greek - I supply the mouth) - an anastomosis is every third vessel that connects the other two - an anatomical concept.

Collateral(collateralis, lat. - lateral) is a lateral vessel that carries out a roundabout flow of blood; the concept is anatomical and physiological.

There are two types of collaterals. Some exist normally and have the structure of a normal vessel, like an anastomosis. Others develop again from anastomoses and acquire a special structure.

To understand collateral circulation, it is necessary to know those anastomoses that connect systems of various vessels through which collateral blood flow is established in the event of vascular injuries, ligation during operations and blockages (thrombosis and embolism).

Anastomoses between the branches of large arterial highways supplying the main parts of the body (aorta, carotid arteries, subclavian, iliac, etc.) and representing separate vascular systems are called intersystemic. Anastomoses between the branches of one large arterial line, limited to the limits of its branching, are called intrasystemic.

These anastomoses have already been noted in the course of the presentation of the arteries.

There are anastomoses between the thinnest intraorgan arteries and veins - arteriovenous anastomoses. Blood flows through them, bypassing the microcirculatory bed when it is overfilled and, thus, forms collateral pathway, directly connecting arteries and veins, bypassing capillaries.

In addition, they take part in collateral circulation thin arteries and veins accompanying great vessels in the neurovascular bundles and components of the so-called perivascular and paranervous arterial and venous beds(A. T. Akilova).

Anastomoses, in addition to their practical significance, are an expression of unity arterial system, which for ease of study we artificially divide into separate parts.

Veins of the systemic circulation

Superior vena cava system

Vena cava superior, superior vena cava, is a thick (about 2.5 cm) but short (5-6 cm) trunk, located on the right and slightly behind the ascending aorta. The superior vena cava is formed from the fusion vv. brachiocephalicae dextra et sinistra behind the junction of the first right rib with the sternum. From here it descends along the right edge of the sternum behind the first and second intercostal spaces and at the level of the upper edge of the third rib, hiding behind the right ear of the heart, flows into right atrium. With its back wall it comes into contact with a. pulmonalis dextra, separating it from the right bronchus, and for a very short distance, at the point of entry into the atrium, with the upper right pulmonary vein; both of these vessels cross it transversely. At the level of the upper edge of the right pulmonary artery, v. flows into the superior vena cava. azygos, leaning over the root right lung(the aorta bends through the root of the left lung). The anterior wall of the superior vena cava is separated from the anterior wall of the chest by a rather thick layer of the right lung.

Brachiocephalic veins

Vv. brachiocephalicae dextra et sinistra, brachiocephalic veins, from which the superior vena cava is formed, in turn, each is obtained by fusion v. subclaviae And v. jugularis internae. The right brachiocephalic vein is shorter than the left, only 2-3 cm long; Having formed behind the right sternoclavicular joint, it goes obliquely downwards and medially to the confluence with the sonominal vein on the left side. In front, the right brachiocephalic vein is covered by mm. sternocleidomastoideus, sternohyoideus and sternothyreoideus, and below the cartilage of the first rib. The left brachiocephalic vein is approximately twice as long as the right one. Having formed behind the left sternoclavicular joint, it goes behind the manubrium of the sternum, separated from it only by fiber and the thymus gland, to the right and down to the confluence with the right brachiocephalic vein; while closely adhering with its lower wall to the convexity of the aortic arch, it crosses the left subclavian artery and the initial parts of the left common carotid artery and brachiocephalic trunk. Vv flows into the brachiocephalic veins. thyreoideae inferiors et v. thyreoidea ima, formed from a dense venous plexus at the lower edge thyroid glands s, veins of the thymus gland, vv. vertebrates, cervicales et thoracicae internae.

Internal jugular vein

V. jugularis interna, internal jugular vein(Fig. 239, 240), removes blood from the cavity of the skull and organs of the neck; starting at the foramen jugulare, in which it forms an extension, bulbus superior venae jugularis internae, the vein descends down, located lateral to a. carotis interna and further down laterally from a. carotis communis. At the lower end of v. jugularis internae before joining it with v. subclavia, a second thickening is formed - bulbus inferior v. jugularis internae; in the neck area above this thickening there are one or two valves in the vein. On its way to the neck, the internal jugular vein is covered by mm. sternocleidomastoideus and omohyoideus. About the sinuses that pour blood into v. jugularis interna, see in the section on the brain. Here we need to mention vv. ophthalmicae superior et inferior, which collect blood from the orbit and flow into the sinus cavernosus, and v. ophthalmica inferior also connects with the plexus pterygoideus (see below).

On its way v. jugularis interna receives the following tributaries:

1. V. facialis, facial vein. Its tributaries correspond to the branches of a. facialis.

2. V. retromandibularis, retromandibular vein, collects blood from temporal region. Further down in v. retromandibularis flows into a trunk that carries blood from the plexus pterygoideus (thick plexus between mm. pterygoidei), after which v. retromandibularis, passing through the thickness of the parotid gland together with the external carotid artery, below the angle of the lower jaw merges with v. facialis.

Most shortcut, connecting the facial vein with pterygoid plexus, is the “anastomotic vein” (v. anastomotica facialis) described by M.A. Sreseli, which is located at the level of the alveolar edge of the lower jaw.

3. Vv. pharyngeae, pharyngeal veins, forming a plexus on the pharynx (plexus pharyngeus), flow either directly into the v. jugularis interna, or flow into v. facialis.

4. V. lingualis, lingual vein, accompanies the artery of the same name.

5. Vv. thyreoideae superiores, superior thyroid veins, collect blood from the upper parts of the thyroid gland and larynx.

6. V. thyreoidea media, middle thyroid vein(or rather, lateralis, according to N. B. Likhacheva), departs from the lateral edge of the thyroid gland and flows into v. jugularis interna. At the lower edge of the thyroid gland there is an unpaired venous plexus - plexus thyreoideus impar, the outflow from which occurs through the vv. thyreoideae superiores in v. jugularis interna, as well as no vv. thyreoideae inferiores and v. thyreoidea ima into the veins of the anterior mediastinum.

External jugular vein

V. jugularis externa, external jugular vein(see Fig. 239, 240 and 241), starting behind the auricle and emerging at the level of the angle of the jaw from the region of the retromandibular fossa, descends, covered with m. platysma, along the outer surface of the sternocleidomastoid muscle, crossing it obliquely downward and posteriorly. Having reached the posterior edge of the sternocleidomastoid muscle, the vein enters the supraclavicular region, where it usually flows through a common trunk with v. jugularis anterior into the subclavian vein. Behind the auricle in v. jugularis externa flow into v. auricularls posterior and v. occipitalis.

Anterior jugular vein

V. jugularis anterior, anterior jugular vein, formed from small veins above hyoid bone, from where it descends vertically. Both vv. jugulares anteriores, right and left, pierce the deep layer of fascia colli propriae, enter the spatium interaponeuroticum suprasternal and flow into the subclavian vein. In the suprasternal space both vv. jugulares anteriores anastomose with each other with one or two trunks. Thus, a venous arch, the so-called drcus venosus jdgult, is formed above the upper edge of the sternum and clavicles. In some cases vv. jugulares anteriores are replaced by one unpaired v. jugularis anterior, which descends along the midline and below flows into the mentioned venous arch, formed in such cases from the anastomosis between vv. jugulares externae (see Fig. 239).

Subclavian vein

V. subclavia, subclavian vein , is a direct continuation of v. axillaris. It is located anterior and inferior to the artery of the same name, from which it is separated by m. scalenus anterior; behind the sternoclavicular joint, the subclavian vein merges with v. jugularis interna, and from the fusion of these veins v. is formed. brachiocephalica.

Veins of the upper limb

The veins of the upper limb are divided into deep and superficial.

Superficial, or subcutaneous, the veins, anastomosing among themselves, form a wide-loop network, from which larger trunks are isolated in places. These trunks are as follows (Fig. 242):

1. V. cephalica*begins in the radial region of the dorsum of the hand, along radial side the forearm reaches the elbow, anastomosing here with v. basilica, runs along the sulcus bicipitalis lateralis, then pierces the fascia and flows into v. axillaris.

* (The cephalic vein, since it was believed that when it is opened, the blood is diverted from the head.)

2. V. basilica* begins on the ulnar side of the dorsum of the hand, goes to the medial part of the anterior surface of the forearm along m. flexor carpi ulnaris to the elbow bend, anastomosing here with v. cephalica through v. mediana cubiti; then it lies in the sulcus bicipitalis medialis, pierces the fascia along half the length of the shoulder and flows into the v. brachialis.

* (The royal vein, since it was opened for diseases of the liver, which was considered the queen of the body.)

3. V. mediana cubiti, median vein elbow area , is an obliquely located anastomosis connecting v. basilica and v. cephalica. V usually flows into it. mediana antebrachii, carrying blood on the palmar side of the hand and forearm. V. mediana ciibiti is of great practical importance, as it serves as a site for intravenous infusions medicinal substances, blood transfusions and taking it for laboratory tests.

Deep veins accompanied by arteries of the same name, usually two each. Thus, there are two: vv. brachiales, ulnares, radiales, interosseae.

Both vv. brachiales at the lower edge of m. pectoralis major merge together and form the axillary vein, v. axillaris, which in the axillary fossa lies medially and anterior to the artery of the same name, partially covering it. Passing under the collarbone, it continues further in the form of v. subclavia. In v. axillaris, except for the above v. cephalica, flows into v. thoracoacromialis(corresponds to the artery of the same name), v. thoracica lateralis(into which v. thoracoepigastrica, a large trunk of the abdominal wall, often flows), v. subscapularis, vv. circumflexae humeri.

Veins - unpaired and semi-unpaired

V. azygos, azygos vein, And v. hemiazygos, hemizygos vein, are formed in the abdominal cavity from the ascending lumbar veins, vv. lumbdles ascendentes, connecting the lumbar veins in the longitudinal direction. They go up behind m. psoas major and penetrate into chest cavity between the muscle bundles of the peduncle of the diaphragm: 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 spine, closely adjacent to the posterior wall of the esophagus. At the level of the IV or V vertebra, it departs from the spine 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 mediastinal organs, nine right lower intercostal veins flow into the azygos vein and through them the veins vertebral plexuses. Near the place where the azygos vein bends over the root of the right lung, it receives v. intercostal superior dextra, formed from the fusion of the upper three right intercostal veins (Fig. 243).

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 upward along the anterior surface of the spine behind the thoracic aorta and ductus thoracicus, flows into v. azygos. It receives branches from the mediastinal organs and the lower left intercostal veins, as well as veins of the vertebral plexuses. The upper left intercostal veins flow into v. hemiazygos accessoria, which goes from top to bottom, located in the same way as v. hemiazygos, on the left lateral surface of the vertebral bodies, and flows into either v. hemiazygos, or directly in v. azygos, bending to the right over the anterior surface of the body of the VII thoracic vertebra.

Veins of the torso walls

Vv. intercostales posteriores, posterior intercostal veins, accompany arteries of the same name in the intercostal spaces, one vein for each artery. The flow of the intercostal veins into the azygos and semi-gypsy veins was discussed above. The following flow into the posterior ends of the intercostal veins near the spine: ramus dorsalis (a branch carrying blood from the deep muscles of the back) and ramus spinalis (from the veins of the vertebral plexuses).

V. thoracica interna, internal thoracic vein, accompanies the artery of the same name; being double along most of its length, it, however, near the first rib merges into one trunk, which flows into v. brachiocephalica of the same side.

Its initial department, v. epigastrica superior, anastomoses with v. epigastrica inferior (joins v. iliaca externa), as well as with the subcutaneous veins of the abdomen (vv. subcutaneae abdominis), forming a large-loop network in subcutaneous tissue. From this network, blood flows upward through v. thoracoepigastrica et v. thoracica lateralis in v. axillaris, and blood flows downwards through v. epigastrica superficialis and v. circumflexa ilium superficialis in femoral vein. Thus, the veins in the anterior abdominal wall form a direct connection between the branching areas of the superior and inferior vena cava. In addition, in the navel area, several venous branches are connected through vv. paraumbilicales with the portal vein system (see below for more on this).

Vertebral plexuses

There are four vertebral venous plexuses - two internal and two external. The internal plexuses, plexus venosi vertebrates interni (anterior et posterior) are located in the spinal canal and consist of a number of venous rings, one for each vertebra. Veins flow into the internal vertebral plexuses spinal cord, as well as vv. basivertebral, emerging from the vertebral bodies on their posterior surface and carrying blood from the spongy substance of the vertebrae. External vertebral plexuses, plexus venosi vertebrates externi, are in turn divided into two: anterior - on the anterior surface of the vertebral bodies (developed mainly in the cervical and sacral areas), and the posterior one, lying on the vertebral arches, covered with deep dorsal and cervical muscles. Blood from the vertebral plexuses flows into the torso area 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, joins v. brachiocephalica, independently or previously connected with v. cervicalis profunda.

Inferior vena cava system

V. cava inferior, inferior vena cava, the thickest venous trunk in the body, lies in the abdominal cavity next to the aorta, to the right of it. It is formed at level IV lumbar vertebra from the confluence of the two common iliac veins slightly below the division of the aorta and immediately to the right of it. The inferior vena cava is directed upward and somewhat to the right, so that the further upward, the more it extends from the aorta. Below, the vein is adjacent to the medial edge of the right m. psoas, then passes to its anterior surface and lies at the top 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.

The tributaries flowing directly into the inferior vena cava correspond to the paired branches of the aorta (except vv. hepaticae). They are divided into parietal veins and splanchnic veins.

Parietal veins: 1) vv. lumbales dextrae et sinistrae, four on each side, correspond to the arteries of the same name, receive anastomoses from the vertebral plexuses; they are connected to each other by longitudinal trunks, vv. lumbales ascendentes; 2) vv. phrenicae inferiores drain into the inferior vena cava where it passes through the groove of the liver.

Veins of the viscera: 1) vv. testiculares in men ( vv. ovaricae in women) begin in the area of ​​the testicles and entwine the arteries of the same name in the form of a plexus (plexus pampiniformis); right v. testicularis flows directly into the inferior vena cava at an acute angle, while the left one flows into the left renal vein at right angles. This last circumstance complicates, according to Hirtl, the outflow of blood and causes the more frequent appearance of dilation of the veins of the left spermatic cord in comparison with the right (in a woman v. ovarica begins at the hilum of the ovary); 2) vv. renales, renal veins, run in front of the arteries of the same name, almost completely covering them; the left one is longer than the right one and passes in front of the aorta; 3) v. suprarenalis dextra flows into the inferior vena cava immediately above the renal vein; v. suprarenalis sinistra usually does not reach the vena cava and flows into the renal vein in front of the aorta; 4) vv. hepaticae, 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 enters through the portal vein and hepatic artery (see Fig. 141).

Portal vein

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 absorption of nutrients occurs, which flow through the portal vein to the liver for neutralization and deposition of glycogen; from the pancreas, where insulin comes from, regulating sugar metabolism; from the spleen, where the breakdown products of blood elements come from, used in the liver to produce bile. The constructive connection of the portal vein with the gastrointestinal tract and its large glands (liver and pancreas) is due, in addition to functional connection, and the commonality of their development (genetic connection) (Fig. 245).

V. portae, portal vein, represents a thick venous trunk located in lig. hepatoduodenal together with the hepatic artery and ductus choledochus. Added up v. portae behind the head of the pancreas from splenic vein and two mesenteric - superior and inferior. Heading to the gate of the liver in the mentioned ligament of peritoneum, it receives vv along the way. gdstricae sinistra et dextra and v. prepylorica and at the porta hepatis divides into two branches that extend into the liver parenchyma. In the liver parenchyma, these branches break up into many small branches that entwine the liver lobules (vv. interlobulares); Numerous capillaries penetrate into the lobules and ultimately form vv. centrales (see "Liver"), which collect 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 the venous trunks that make up the portal vein, and the second is located in the substance of the liver, where the portal vein disintegrates into its final branches.

V. liertalis, splenic vein, carries blood from the spleen, from the stomach (through v. gastroepiploica sinistra and vv. gastricae breves) and from the pancreas, along the upper edge of which behind and below the artery of the same name it goes 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 receives venous branches from the small intestine (vv. intestinales), from the cecum, from the ascending colon and transverse colon(v. colica dextra et v. colica media) and, passing behind the head of the pancreas, connects with the inferior mesenteric vein. V. mesenterica inferior begins from the venous plexus of the rectum, plexus venosus rectalis. Heading upward from here, along the way it receives inflows 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, it, having previously connected with the splenic vein or independently, merges with the superior mesenteric vein.

Common iliac veins

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, while the left one lies just below behind the artery of the same name, then lies medial to 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 is in turn composed of two veins: the internal iliac vein ( v. iliaca interna) and external iliac ( v. iliaca externa).

Internal iliac vein

V. iliaca interna, internal iliac vein, in the form of a short but thick trunk, is located behind the artery of the same name. The tributaries that make up the internal iliac vein correspond to the arterial branches of the same name, and usually outside the pelvis these tributaries are present in double number; entering the pelvis, they become single. In the area of ​​tributaries of the internal iliac vein, a number of venous plexuses are formed, anastomosing with each other.

1. Plexus venosus sacralis composed of sacral veins - lateral and median.

2. Plexus venosus rectalis s. hemorrhoidalis (BNA) - plexus in the walls of the rectum. There are three plexuses: submucosal, subfascial and subcutaneous. The submucosal, or internal, venous plexus, plexus rectalis interims, in the region of the lower ends of the columnae rectalis is a series of venous nodules arranged in the form of a ring. The efferent veins of this plexus pierce the muscular lining of the intestine and merge with the veins of the subfascial, or external, plexus, plexus rectalis externus. From the latter comes v. rectalis superior and vv. rectales mediae, accompanying the cognate arteries. First through the bottom mesenteric vein flows into the portal vein system, the second - into the inferior vena cava system, through the internal iliac vein. In the area of ​​the external sphincter of the anus, a third plexus is formed, the subcutaneous one - plexus subcutaneus ani, from which vv. rectales inferiores, flowing into v. Pudenda interna.

3. Plexus venosus vesicalis located in the bottom of the bladder; through vv. vesicales, blood from this plexus flows into the internal iliac vein.

4. Plexus venosus prostaticus located between bladder and pubic fusion, covering the man’s prostate gland and seminal vesicles. The unpaired v flows into the plexus venosus prostaticus. dorsalis penis. In a woman, the dorsal vein of the man's penis corresponds to v. dorsalis clitoridis.

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

Portocaval and cavacaval anastomoses

The roots of the portal vein anastomose with the roots of the veins belonging to the systems of the superior and inferior vena cava, forming the so-called portocaval anastomoses, which are of practical importance.

If we compare the abdominal cavity with a cube, then these anastomoses will be located on all its sides, namely:

1. At the top, in the pars abdominalis of the esophagus - between the roots of v. gastricae sinistrae, flowing into the portal vein, and vv. esophageae, flowing into vv. azygos and hemyazygos and further in v. cava superior.

2. Below, in the lower part of the rectum, between v. rectalis superior, flowing through v. mesenterica inferior into the portal vein, and vv. rectales media (influx of v. iliaca interna) et inferior (influx of v. pudenda interna), flowing into v. iliaca interna and further v. iliaca communis - from system v. cava inferior.

3. In front, in the navel area, where the vv. is anastomosed with its tributaries. paraumbilicales, running in the thickness of lig. teres hepatis to the portal vein, v. epigastrica superior from system v. cava superior (v. thoracica interna, v. brachiocephalica) and v. epigastrica inferior - from system v. cava inferior (v. iliaca externa, v. iliaca communis).

This results in portacaval and cavacaval anastomoses, which serve as a roundabout route for the outflow of blood from the portal vein system when there are obstacles to it in the liver (cirrhosis). In these cases, the veins around the navel dilate and become characteristic appearance("jellyfish head") *.

* (Extensive connections of the veins of the thymus and thyroid glands with the veins of surrounding organs are involved in the formation of cavacaval anastomoses (N. B. Likhacheva).)

4. Behind, in the lumbar region, between the roots of the veins of the mesoperitoneal sections of the colon (from the portal vein system) and the parietal vv. lumbales (from the v. cava inferior system). All these anastomoses form the so-called Retzius system.

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

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

External iliac vein

V. iliaca externa is a direct continuation of v. femoralis, which, after passing under the Poupartian ligament, is called the external iliac vein. Running medially from the artery and behind it, in the region of the sacroiliac joint it merges with the internal iliac vein and forms the common iliac vein; accepts two tributaries, sometimes flowing into one trunk: v. epigastrica inferior And v. circumflexa ilium profunda, accompanying the arteries of the same name.

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

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

From the saphenous veins of the lower limb, the largest are two trunks: v. saphena magna and v. saphena parva. Vena saphena magna originates on the dorsal surface of the foot from the rete venosum dorsale pedis and arcus venosus dorsalis pedis. Having received several inflows from the side of the sole, it is directed upward along the medial side of the lower leg and thigh. IN upper third of the thigh, it bends onto the anteromedial surface and, lying on the fascia lata, is directed towards the hiatus saphenus. At this point v. saphena magna flows into the femoral vein, spreading over the lower horn of the falciform margin. Quite often v. saphena magna is double, and both of its trunks can flow separately into the femoral vein. Of the other subcutaneous tributaries of the femoral vein, mention should be made of v. epigastrica superficialis, v. circumflexa ilium superficialis, vv. pudendae externae, accompanying the arteries of the same name. They flow partly directly into the femoral vein, partly into the v. saphena magna at its confluence with the hiatus saphenus region. V. saphena parva begins on the lateral side of the dorsal surface of the foot, bends around the lateral malleolus from below and behind and rises further along the back surface of the lower leg; first it runs along the lateral edge of the Achilles tendon, and then up the middle posterior section shins corresponding to the groove between the heads of m. gastrocnemia. Having reached the lower angle of the popliteal fossa, v. saphena parva flows into the popliteal vein. V. saphena parva is connected by branches to v. saphena magna.