Superior vena cava has no valves; collects blood from areas of the head and neck, upper extremities, chest and abdominal (partially) cavities. The superior vena cava is formed by the fusion of the right and left brachiocephalic veins behind the junction of the I right rib with the sternum. Vienna goes straight down. At the level of junction of the third costal cartilage with the sternum, the superior vena cava flows into the right atrium. Slightly higher than the confluence of the superior vena cava into the right atrium, an unpaired vein opens into it on the right, and on the left several pericardial veins and small mediastinal veins (from the connective tissue and lymph nodes of the mediastinum).

Superior vena cava and its tributaries. Formation of the superior vena cava and inferior vena cava. Veins of the posterior wall of the trunk. Front view. The parietal layers of the pleura and peritoneum are removed. (-internal jugular vein; 2-left brachiocephalic vein "3-aortic arch; 4-esophagus (cut off); 5-semi-unpaired vein; 6-left ascending lumbar vein; 7-left common iliac vein; 8-left internal iliac vein; 9-left external iliac vein; IO-right external iliac vein; 11-right internal iliac vein; 12-median sacral vein; 13-inferior vena cava; 14-right ascending lumbar vein; 15-lumbar veins; 16-unpaired vein; 17-posterior intercostal veins; 18-superior vena cava; 19-right brachiocephalic vein; 20-shoulder head trunk; 21-right subclavian vein; 22-right external jugular vein; 23-right internal jugular vein.

Unpaired vein collects blood from the walls of the chest and abdominal cavities, as well as from the organs of the posterior mediastinum. The unpaired vein begins from the right ascending lumbar vein, which is a continuation of the anterior sacral veins. In the abdominal cavity, the right ascending lumbar vein anastomoses with the right lumbar veins flowing into the inferior vena cava.

The 9 lower right intercostal veins flow into the azygos vein, the right upper intercostal vein, which is formed from the three upper right intercostal veins. The esophageal, bronchial, pericardial and mediastinal veins also flow into the azygos vein. A large tributary of the azygos vein is the azygos vein.

Semi-unpaired vein starts from the left ascending lumbar vein, originating in the small pelvis from the anterior sacral veins. The left ascending lumbar vein forms an anastomosis with the left lumbar veins (tributaries of the inferior vena cava). Having passed through the diaphragm, the left ascending lumbar vein passes into a semi-unpaired vein. The semi-unpaired vein goes up, then forms a bend to the right, passes behind the aorta, esophagus and thoracic duct, and at the level of the VIII thoracic vertebra flows into the unpaired vein. The lower left posterior intercostal veins flow into the semi-unpaired vein, as well as the accessory semi-unpaired vein, which is formed from 4-7 upper left posterior intercostal veins. The esophageal and posterior mediastinal veins flow into the semi-unpaired vein.

Posterior intercostal veins pass in the intercostal spaces, under the groove of the lower edge of the corresponding rib. The veins of the back (from the deep muscles of the back), spinal veins, veins of the external and internal vertebral plexuses flow into each posterior intercostal vein. Two to three lower posterior intercostal veins receive blood from the diaphragm and abdominal muscles.

Internal vertebral venous plexus is located in the spinal canal, on the inner surface of its walls, outward from the dura mater along the entire length of the spinal column. In the veins of this plexus, blood flows from the spinal column, spinal cord and its membranes.

External vertebral venous plexus located on the surfaces of the vertebral bodies and on the deep muscles of the neck. The veins of the deep muscles of the neck, the veins of the vertebral bodies flow into it. From the external vertebral plexuses, blood flows into the posterior intercostal, lumbar, sacral veins and directly into the azygos and semi-unpaired veins.

Brachiocephalic veins are formed when the internal jugular and subclavian veins of their side merge. The right and left brachiocephalic veins merge behind the junction of the first costal cartilage with the sternum to form the superior vena cava. The vertebral, deep cervical and internal thoracic veins flow into each brachiocephalic vein. The brachiocephalic vein also receives the pericardial, bronchial, esophageal, mediastinal, thymic, and lower thyroid veins from the unpaired venous plexus located on the anterior surface of the thyroid gland. The highest (uppermost) intercostal vein also flows into the brachiocephalic vein, collecting blood from the upper 3-4 posterior intercostal veins.

The vertebral vein goes along with the artery of the same name in the canal of the transverse processes of the cervical vertebrae; collects blood from the venous plexus located inside the spinal canal, from the suboccipital venous plexus.

Deep vein of the neck formed from the veins of the external vertebral plexus; removes blood from the deep veins of the occiput, vertebral plexus.

Internal chest veins among the two they begin from the superior epigastric and musculophrenic veins. The superior epigastric vein removes blood from the rectus abdominis muscle, its vagina, anastomoses at the level of the navel with the inferior epigastric vein (the inflow of the external iliac vein). The muscular-diaphragmatic vein is directed upward from the diaphragm, takes the intercostal veins from the five lower intercostal spaces. The mediastinal veins from the pleura and mediastinal tissue, thymus veins, bronchial veins from the lower trachea and the main bronchus of their side also flow into the internal thoracic veins. The pericardial-diaphragmatic vein flows into the internal thoracic veins. The internal thoracic vein also receives the sternal veins, breast veins and anterior intercostal veins.

On the right, the internal thoracic veins usually flow into the superior vena cava, on the left - into the left brachiocephalic vein.

Superior vena cava - a short vessel 5-8 cm long and 21-25 mm wide. Formed by the fusion of the right and left brachiocephalic veins. The superior vena cava receives blood from the walls of the chest and abdominal cavities, organs of the head and neck, and the upper extremities.

Veins of the head and neck. The main venous collector from the organs of the head and neck is the internal jugular vein and partially the external jugular vein (Fig. 94).

Fig. 94. Veins of the head and face:

1 - occipital vein; 2 - pterygoid (venous) plexus; 3 - maxillary vein; 4 - submandibular vein; 5 - internal jugular vein; 6 - external jugular vein; 7 - chin vein; 8 - facial vein; 9 - frontal vein; 10- superficial temporal vein

Internal jugular vein - a large vessel that receives blood from the head and neck. It is a direct continuation of the sigmoid sinus of the dura mater of the brain; originates from the jugular opening of the skull, goes down and, together with the common carotid artery and the vagus nerve, forms the neurovascular bundle of the neck. All tributaries of this vein are divided into intra- and extracranial.

TO intracranial include the veins of the brain that collect blood from the cerebral hemispheres; meningeal veins - blood comes from the meninges; diploic veins - from the bones of the skull; eye veins - blood comes from the eyes and nose; veins of the labyrinth - from the inner ear. These veins carry blood to the venous sinuses (sinuses) of the hard shell of the brain. The main sinuses of the dura mater are superior sagittal sinus, which runs along the upper edge of the cerebral crescent and flows into the transverse sinus; inferior sagittal sinus runs along the lower edge of the cerebral crescent and flows into the straight sinus; straight sine connects with transverse; the cavernous sinus is located around the Turkish saddle; transverse sinus laterally enters the sigmoid sinus, which passes into the internal jugular vein.

Sinuses of the dura mater using emissary veins connect to the veins of the outer cover of the head.

TO extracranial tributaries internal jugular vein facial vein - collects blood from the face and mouth; submandibular vein - takes blood from the scalp, auricle, masticatory muscles, part of the face, nose, and lower jaw.

The pharyngeal veins, lingual, and upper thyroid veins flow into the internal jugular vein in the neck. They collect blood from the walls of the pharynx, tongue, floor of the mouth, submandibular salivary glands, thyroid gland, larynx, sternocleidomastoid muscle.

External jugular vein formed as a result of joining its two tributaries: 1) the fusion of the occipital and posterior ear veins; 2) anastomosis with the submandibular vein. Collects blood from the skin of the occipital and posterior regions. The suprascapular vein, the anterior jugular vein and the transverse veins of the neck flow into the external jugular vein. These vessels collect blood from the skin of the areas of the same name.

Anterior jugular vein formed from the small veins of the chin region, penetrates into the interfascial supra-chest space, in which the right and left anterior jugular veins, connecting, form jugular venous arch.The latter flows into the external jugular vein of the corresponding side.

Subclavian vein - unpaired trunk, is a continuation of the axillary vein, merges with the internal jugular vein, collects blood from the upper limb.

Veins of the upper limb. The superficial and deep veins of the upper limb are distinguished. Superficial veins, connecting with each other, form venous networks, from which the two main saphenous veins of the arm are then formed: lateral saphenous vein of the hand - located on the side of the radius and flows into the axillary vein and medial saphenous vein of the hand - located on the ulnar side and flows into the brachial vein. In the ulnar bend, the lateral and medial saphenous veins are connected by a short intermediate vein of the elbow.

The deep veins of the upper limb include deep palmar veins. They accompany the arteries of the same name in two, form superficial and deep venous arches. Palmar digital and palmar metacarpal veins flow into the superficial and deep palmar venous arches, which then pass into the deep veins of the forearm - paired ulnar and radial veins. Along the way, veins from muscles and bones join them, and in the region of the cubital fossa they form two brachial veins. The latter take blood from the skin and muscles of the shoulder, and then, before reaching the axillary region, at the level of the tendon of the widest muscle of the back, they are connected into one trunk - axillary vein. Veins from the muscles of the shoulder girdle and shoulder, and also partially from the muscles of the chest and back, flow into this vein.

At the level of the outer edge of the I rib, the axillary vein passes into subclavian. It is joined by the non-permanent transverse vein of the neck, the subscapular vein, as well as the small thoracic and dorsal scapular veins. The place where the subclavian vein meets the internal jugular vein on each side is called the venous angle. As a result of this connection, brachiocephalic veins, where the veins of the thymus, mediastinum, pericardial sac, esophagus, trachea, muscles of the neck, spinal cord, etc. flow into. Further, when connected, the brachiocephalic veins form the main trunk - superior vena cava. The veins of the mediastinum, pericardial sac and unpaired vein, which is a continuation of the right ascending lumbar vein. The unpaired vein collects blood from the walls of the abdominal and chest cavities (Fig. 95). It flows into the unpaired vein semi-unpaired vein, to which the veins of the esophagus, mediastinum, partly the posterior intercostal veins join; they are a continuation of the left ascending lumbar vein.

Inferior vena cava system

The inferior vena cava system is formed from the joints that collect blood from the lower extremities, the walls and organs of the pelvis and the abdomen.

Inferior vena cava formed by connecting the left and right common iliac veins. This thickest venous trunk is located retroperitoneally. It originates at the level of the IV-V lumbar vertebrae, is located to the right of the abdominal aorta, goes up to the diaphragm and through the hole of the same name into the posterior mediastinum. Penetrates into the pericardial cavity and flows into the right atrium. Along the way, parietal and visceral vessels join the inferior vena cava.

Parietal venous tributaries include lumbar veins (3-4) on each side, collect blood from the venous plexuses of the spine, muscles and skin of the back; ana-stomoses using the ascending lumbar vein; lower phrenic veins (right and left) - blood comes from the lower surface of the diaphragm; flow into the inferior vena cava.

The group of visceral tributaries includes testicular (ovarian) veins, collecting blood from a testicle (ovary); renal veins - from the kidney; adrenal - from the adrenal glands; hepatic - carry blood from the liver.

Venous blood from the lower extremities, walls and pelvic organs is collected in two large venous vessels: the internal iliac and external iliac veins, which, when connected at the level of the sacroiliac joint, form the common iliac vein. Both common iliac veins then drain into the inferior vena cava.

Internal iliac a vein is formed from veins that collect blood from the pelvic organs and belong to the parietal and visceral tributaries.

To the group parietal tributaries includes the superior and inferior gluteal veins, obturator, lateral sacral and ilio-lumbar veins. They collect blood from the muscles of the pelvis, thighs, and abdomen. All veins have valves. TO visceral tributaries include the internal genital vein - collects blood from the perineum, external genital organs; urinary veins - blood comes from the bladder, vas deferens, seminal vesicles, prostate (in men), vagina (in women); lower and middle rectal veins - collect blood from the walls of the rectum. Visceral tributaries, connecting with each other, form around the pelvic organs (bladder, prostate, rectum) venous plexus.

The veins of the lower limb are aimed into superficial and deep, which are connected by anastomoses.

In the area of \u200b\u200bthe foot, the saphenous veins form the plantar and dorsal venous networks of the foot, into which the digital veins flow. From the venous networks, the dorsal metatarsal veins are formed, which give rise to the great and small saphenous veins of the leg.

Large saphenous vein of the leg is a continuation of the medial dorsal metatarsal vein, along the way it takes numerous superficial veins from the skin and flows into the femoral vein.

Small saphenous vein of the leg formed from the lateral part of the saphenous network of the dorsum of the foot, flows into the popliteal vein, collects blood from the saphenous veins of the plantar and dorsum of the foot.

Deep veins of the lower limb are formed by digital veins that merge into the plantar and dorsal metatarsal veins. The latter flow into the plantar and dorsal venous arches of the foot. From the plantar venous arch, blood flows through the plantar metatarsal veins into the posterior tibial veins. From the dorsal venous arch, blood enters the anterior tibial veins, which along the way collect blood from the surrounding muscles and bones and, when connected, form the popliteal vein.

Popliteal vein takes the small knee veins, the small saphenous vein and goes into the femoral vein.

Femoral vein rising up, it goes under the inguinal ligament and passes into the external iliac vein.

The deep vein of the thigh flows into the femoral vein; veins surrounding the femur; superficial epigastric veins; external genital veins; large saphenous vein of the leg. They collect blood from the muscles and fascia of the thigh and pelvic girdle, hip joint, lower abdominal wall, and external genitalia.

Portal vein system

From the unpaired organs of the abdominal cavity, except for the liver, blood is first collected in the portal vein system, through which it goes to the liver, and then through the hepatic veins to the inferior vena cava.

Portal vein (Fig. 96) - a large visceral vein (length 5-6 cm, diameter 11-18 mm), formed by connecting the inferior and superior mesenteric and splenic veins. The veins of the stomach, small and large intestine, spleen, pancreas and gallbladder flow into the portal vein. Then the portal vein goes to the gate of the liver and enters its parenchyma. In the liver, the portal vein is divided into two branches: right and left, each of them, in turn, is divided into segmental and smaller ones. Inside the liver lobules, they branch out into wide capillaries (sinusoids) and flow into the central veins, which pass into the sublobular veins. The latter, connecting, form three to four hepatic veins. Thus, blood from the organs of the digestive tract passes through the liver, and then only enters the system of the inferior vena cava.

Superior mesenteric vein goes to the roots of the mesentery of the small intestine. Its tributaries are the veins of the jejunum and ileum, pancreatic, pancreatoduodenal, sub-iliocolic, right gastroepiploic, right and middle colon veins and the vein of the appendix. The superior mesenteric vein receives blood from the above organs.

Fig. 96. Portal vein system:

1 - superior mesenteric vein; 2 - stomach; 3 - left gastroepiploic vein; 4 - left gastric vein; 5- spleen; 6- the tail of the pancreas; 7- splenic vein; 8- inferior mesenteric vein; 9- the descending colon; 10 - rectum; 11 - lower rectal vein; 12- middle rectal vein; 13- superior rectal vein; 14 - ileum; 15 - ascending colon; 16 - the head of the pancreas; 17, 23- right gastroepiploic vein; 18- portal vein; 19- biliary vein; 20 - gallbladder; 21 - duodenum; 22 - liver; 24- gatekeeper vein

Splenic vein collects blood from the spleen, stomach, pancreas, duodenum and greater omentum. The tributaries of the splenic vein are short gastric veins, pancreatic and left gastroepiploic veins.

Inferior mesenteric vein formed as a result of the fusion of the superior rectal vein, left colic and sigmoid veins; it collects blood from the walls of the upper rectum, the sigmoid colon, and the descending colon.

Lymphatic system

The lymphatic system is part of the cardiovascular system (Fig. 97). Through the lymphatic system, water, proteins, fats, metabolic products return from the tissues to the circulatory system.

Fig. 97. Lymphatic system (scheme):

1,2 - parotid lymphatic minds; 3 - cervical nodes; 4 - thoracic duct; 5, 14 - axillary lymph nodes; 6, 13 - elbow lymph nodes; 7, 9- inguinal lymph nodes; 8 - superficial lymphatic vessels of the leg; 10 - iliac nodes; 11 - mesenteric nodes; 12 - cistern of the thoracic duct; 15 - subclavian nodes; 16 - occipital nodes; 17- submandibular nodes

The lymphatic system performs a number of functions: 1) maintains the volume and composition of tissue fluid; 2) maintains a humoral connection between the tissue fluid of all organs and tissues; 3) absorption and transfer of nutrients from the digestive tract to the venous system; 4) transfer to the bone marrow and to the site of injury of migrating lymphocytes, plasma cells. Cells of malignant neoplasms (metastases) and microorganisms are transferred through the lymphatic system.

The human lymphatic system consists of lymphatic vessels, lymph nodes and lymphatic ducts.

The beginning of the lymphatic system is lymphatic capillaries. They are found in all organs and tissues of the human body, except for the brain and spinal cord and their membranes, skin, placenta, spleen parenchyma. The walls of the capillaries are thin single-layer epithelial tubes with a diameter of 10 to 200 microns, have a blind end. They stretch easily and can expand 2-3 times.

When several capillaries merge, lymphatic vessel. The first valve is also located here. Depending on the location, the lymphatic vessels are divided into superficial and deep. Through the vessels, the lymph goes to the lymph nodes that correspond to a given organ or body part. Depending on where the lymph is collected from, visceral, somatic (parietal) and mixed lymph nodes are isolated. The first collect lymph from internal organs (tracheobronchial, etc.); the second - from the musculoskeletal system (popliteal, elbow); still others - from the walls of hollow organs; fourth - from deep structures of the body (deep cervical nodes).

The vessels through which lymph enters the node are called bringing, and the vessels leaving the knot gates - enduring lymphatic vessels.

The large lymphatic vessels form the lymphatic trunks, which, when fused, form lymphatic ducts, flowing into the venous nodes or into the terminal sections of the veins forming them.

There are six such large lymphatic ducts and trunks in the human body. Three of them (thoracic duct, left jugular and left subclavian trunks) flow into the left venous angle, three others (right lymphatic duct, right jugular and right subclavian trunks) - into the right venous angle.

Thoracic duct formed in the abdominal cavity, behind the peritoneum, at the level of the XII thoracic and II lumbar vertebrae as a result of the fusion of the right and left lumbar lymphatic trunks. Its length is 20-40 cm, it collects lymph from the lower extremities, walls and organs of the pelvis, abdominal cavity and left half of the chest. From the abdominal cavity, the thoracic duct goes through the aortic opening into the chest cavity, and then goes into the neck and opens into the left venous angle or into the terminal sections of the veins that form it. It flows into the cervical part of the duct broncho-mediated trunk, which collects lymph from the left half of the chest; left subclavian trunk carries lymph from the left hand; left jugular trunk comes from the left half of the head and neck. There are 7-9 valves on the way of the thoracic duct, which prevent lymph flow back.

From the right half of the head, neck, upper limb, organs of the right half of the chest, lymph collects right lymphatic duct. It is formed from the right subclavian, right broncho-mediastinal and jugular trunks and flows into the right venous angle.

Lymphatic vessels and nodes of the lower limb are divided into superficial and deep. Superficial vesselscollect lymph from the skin and subcutaneous tissue of the foot, lower leg and thigh. They flow into the superficial inguinal lymph nodes, which are located below the inguinal ligament. In the same nodes, lymph flows from the anterior abdominal wall, gluteal region, external genitalia, perineum and part of the pelvic organs.

In the popliteal fossa are popliteal lymph nodes, which collect lymph from the skin of the foot, lower leg. The outflow ducts of these nodes flow into deep lymph nodes in the groin.

Deep lymphatic vessels collect lymph from the foot, lower leg into the popliteal lymph nodes, and from the tissues of the thigh into the deep inguinal nodes, the outflowing vessels of which flow into the external iliac nodes.

Depending on the location pelvic lymph nodes are divided into parietal and visceral. The first group includes external, internal and common iliac nodes, which collect lymph from the walls of the pelvis. Visceral lymph nodes relative to the pelvic organs are peri-vesical, peri-uterine, peri-vaginal, peri-rectal and collect lymph from the corresponding organs.

The efferent vessels of the internal and external iliac nodes reach common iliac lymph nodes, from which the lymph goes to the lumbar nodes.

IN lymph nodes in the abdomen lymph is collected from the parietal and visceral lymph nodes and vessels of the abdominal cavity organs, lower back.

The lymphatic vessels of the lumbar lymph nodes form the right and left lumbar trunks, which give rise to the thoracic duct.

Lymphatic vessels and nodes of the chest cavity collect lymph from the walls of the chest and organs located in it.

Depending on the topography of the organs, lymph nodes are distinguished parietal (periosternal, intercostal, upper diaphragmatic) and visceral (anterior and posterior mediastinal, bronchopulmonary, lower and upper tracheo-bronchial). They collect lymph from their respective organs.

In the head region, lymph flows from the occipital, mastoid, superficial and deep parotid, facial, chin, submandibular lymph nodes.

By topographic location lymph nodes of the neckare divided into cervical and lateral cervical, as well as superficial and deep. Lymph comes to them from adjacent organs.

When connected, the lymphatic vessels of the neck on each side form jugular trunk. On the right, the jugular trunk joins the right lymphatic duct or flows independently into the venous angle, and on the left - to the thoracic duct.

In the upper limb, lymph is first collected along the superficial and deep vessels into the regional ulnar and axillary lymph nodes. They are located in the holes of the same name. Elbow nodes are divided into superficial and deep. Axillary lymph nodes also divided into superficial and deep. By localization, lymph nodes in the axillary region are divided into medial, lateral, posterior, lower, central and apical. Superficial lymphatic vessels, accompanying the saphenous veins of the upper extremities, form a medial, middle and lateral group.

Coming out of the deep axillary lymph nodes, the vessels form the subclavian trunk, which flows into the thoracic duct on the left, and into the right lymphatic duct on the right.

The lymph nodes are peripheral organs of the immune system that act as biological and mechanical filters and are usually located around blood vessels, usually in groups of several to ten nodes or more.

The lymph nodes are pinkish-gray in color, rounded, ovoid, bean-shaped and ribbon-shaped, their length ranges from 0.5 to 30-50 mm (Fig. 98).

Fig. 98. The structure of the lymph node:

1 - capsule; 2 - trabecula; 3 - crossbar; 4 - cortical substance; 5 - follicles; 6- bringing lymphatic vessels; 7- medulla; 8- outflowing lymphatic vessels; 9- lymph node gate

Each lymph node is covered with a connective tissue capsule outside. The lymph node on one side has veins and outflowing lymphatic vessels. The carrying vessels approach the node from the convex side. Thin partitions extend inside the node from the capsule and are interconnected in the depth of the node.

On the section of the node, the peripheral dense cortex is visible, which consists of the cortical and paracortical zones, and the central medulla. In the cortex and medulla, B- and T-lymphocytes are formed and a leukocyte factor is produced, which stimulates cell proliferation. Mature lymphocytes enter the sinuses of the nodes, and then are carried with the lymph into the discharge vessels.

Hematopoietic organs

Bone marrow is the organ of blood cell formation. It forms and multiplies stem cells, which give rise to all types of blood cells and the immune system. Therefore, the bone marrow is also called an immune organ. Stem cells have a great ability to multiply and form a self-sustaining system.

As a result of numerous complex transformations and differentiation in three directions (erythropoiesis, granulopoiesis and thrombocytopoiesis), stem cells become shaped elements. Stem cells also form cells of the immune system - lymphocytes, and from the latter - plasma cells (plasma cells).

Allocate red bone marrow, which is located in the spongy substance of flat and short bones, and yellow bone marrow, which fills the cavity of the diaphysis of long tubular bones.

The total bone marrow mass of an adult is about 2.5-3.0 kg, or 4.5-4.7% of the body weight.

Red bone marrow consists of myeloid tissue, which also includes reticular and hematopoietic tissue, while yellow bone marrow consists of adipose tissue that has replaced the reticular tissue. With significant blood loss, the yellow bone marrow is again replaced by the red bone marrow.

Spleen (lien, splen) performs the functions of a peripheral organ of the immune system. It is located in the abdominal cavity, in the region of the left hypochondrium, at the level from IX to XI ribs. The mass of the spleen is about 150-195 g, length 10-14 cm, width 6-10 cm and thickness 3-4 cm. The spleen is covered on all sides by the peritoneum, which grows tightly with the fibrous membrane and is fixed with the help of gastro-splenic and diaphragmatic splenic ligaments. It has a red-brown color, soft texture. Connective tissue partitions - trabeculae, between which the parenchyma is located, depart from the fibrous membrane inside the organ. The latter is formed by white and red pulp. The white pulp consists of splenic lymph nodes and lymphoid tissue around the intraorgan arteries. The red pulp is formed by loops of reticular tissue filled with erythrocytes, lymphocytes, macroorganisms and other cellular elements, as well as venous sinuses.

On the concave surface are the gates of the spleen, they are the vessels and nerves.

In the spleen, erythrocytes are destroyed, as well as differentiation of T and B lymphocytes.

Thymus (thymus), or thymus, refers to the central organs of lymphocytopoiesis and immunogenesis. In ty-mus, stem cells coming from the bone marrow,. after a series of transformations they become T-lymphocytes. The latter are responsible for the reactions of cellular immunity. Then T-lymphocytes enter the blood and lymph, leave the thymus and pass into the thymus-dependent zones of the peripheral organs of immunogenesis. In the thymus, stromal epithelial cells produce thymosin (hemopoetic factor), which stimulates the proliferation of lymphoblasts. In addition, other biologically active substances (factors with the properties of insulin, calcitonin, growth factors) are produced in the thymus.

Thymus is an unpaired organ, consists of left and right lobes, connected by loose fiber. From above, the thymus gland narrows, and from below it expands. The left lobe in many cases can be longer than the right.

The thymus is located in front of the superior mediastinum, in front of the upper part of the pericardium, aortic arch, left brachiocephalic and superior vena cava. On the sides, the right and left mediastinal pleura are adjacent to the thymus. The anterior surface of the thymus connects to the sternum. The organ is covered with a thin connective tissue capsule, from which partitions extend inward, dividing the substance of the gland into small lobules. The parenchyma of the organ consists of the peripheral part of the cortex and the central part of the medulla. The thymic stroma is represented by reticular tissue. Between the fibers and the cells of the reticular tissue are thymic lymphocytes (thymocytes), as well as multi-process epithelial cells (epithelio-reticulocytes). In addition to the immunological function and the function of blood formation, endocrine activity is also characteristic of the thymus.

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Superior vena cava (v. cava superior),a component of the systemic circulation, drains blood from the upper half of the body - head, neck, upper limbs, chest wall.

The superior vena cava is formed from the fusion of two brachiocephalic veins (behind the junction of the first right rib with the sternum) and lies in the upper part of the mediastinum. At the level of the II rib, it penetrates into the pericardial cavity (pericardial sac) and flows into the right atrium.

The diameter of the superior vena cava reaches 20-22 mm, its length is 7-8 cm. Near the heart, a large azygos vein, as well as mediastinal and pericardial veins, flow into it.

Unpaired vein

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Unpaired vein (v. azygos)starts in the abdomen, where it is called right ascending lumbar vein.It originates from numerous tributaries - the parietal veins of the abdominal cavity and forms anastomoses with the veins of the paravertebral plexus, the common iliac and sacral veins.

Rising along the right side of the vertebral bodies, it passes through the diaphragm and follows behind the esophagus called the azygos vein. The diaphragmatic and right intercostal veins, veins from the mediastinal organs (pericardium, esophagus, bronchi) and the semi-unpaired vein flow into it. There are two valves at the place where the azygos vein flows into the superior vena cava.

Semi-unpaired vein

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Semi-unpaired vein (v, hemiazygos)thinner than unpaired, begins in the abdominal cavity called the left ascending lumbar vein. In the thoracic cavity, it lies in the posterior mediastinum to the left of the aorta, takes the left intercostal, esophageal and mediastinal veins, as well as an additional semi-unpaired vein, which forms when the upper intercostal veins merge. The semi-unpaired vein basically repeats the course of the azygos vein, into which it flows at the level of the VIII thoracic vertebra, crossing the spine.

Intercostal veins

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Intercostal veins (vv. intercostales)accompany the arteries of the same name, together with which, as well as with the nerves, they form the neurovascular bundles of the intercostal space.

The anterior intercostal veins flow, respectively, into the right and left internal thoracic veins accompanying the artery of the same name, and the posterior ones - into the unpaired, semi-unpaired, left brachiocephalic and accessory semi-unpaired veins. There are valves in the mouths of the intercostal veins.

A dorsal branch flows into each posterior intercostal vein, collecting blood from the muscles and skin of the back, as well as from the spinal cord, its membranes and the venous plexus of the spine.

Brachiocephalic vein

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Brachiocephalic vein (v. brachiocephalisa)arises behind the sternoclavicular joint in the venous angle from the junction of two veins: the internal jugular and subclavian. The left vein is almost twice as long as the right and runs in front of the branches of the aortic arch. Behind the place of attachment of the I rib to the sternum, the right and left veins are connected and form the superior vena cava. The brachiocephalic vein collects blood from the veins accompanying the branches of the subclavian artery, and in addition, from the veins of the thyroid and thymus glands, larynx, trachea, esophagus, from the venous plexuses of the spine, deep veins of the neck and head, veins of the upper intercostal muscles and the mammary gland.

The most significant tributaries of the brachiocephalic veins are the thyroid, mediastinal, vertebral, internal thoracic and deep cervical veins. Through the terminal branches of the vein, anastomoses are established between the systems of the superior and inferior vena cava. So the internal thoracic veins begin in the anterior abdominal wall as the superior epigastric veins. They anastomose with the inferior epigastric veins belonging to the inferior vena cava system.

Internal jugular vein

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Internal jugular vein (and. jugularis interna)begins in the jugular opening of the skull as a direct continuation of the sigmoid sinus of the dura mater and descends along the neck in the same neurovascular bundle with the carotid artery and the vagus nerve.

The internal jugular vein (together with the external jugular) collects blood from the head and neck, i.e. from areas that are supplied by the common carotid artery, and, in particular, from the sinuses of the dura mater, into which blood flows from the veins of the brain. In addition, in the cranial cavity, veins from the orbit, inner ear, cancellous bones of the roof of the skull and meninges flow into the internal jugular vein. Of the extracranial branches, the largest are facial vein (v. facialis),accompanying the facial artery and submandibular vein.The latter collects blood from the temporal region, ear, mandibular joint, parotid salivary gland, jaw and masticatory muscles. In the neck, tributaries from the pharynx, tongue and thyroid gland flow into the internal jugular vein.

Throughout its length, the vein and its tributaries have valves.

External jugular vein

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External jugular vein (v. jugularis externa)is formed at the level of the angle of the lower jaw as a result of the fusion of the mandibular and posterior auricular veins and descends along the outer surface of the sternocleidomastoid muscle, covered by the fascia and the subcutaneous muscle of the neck. The vein flows into the subclavian or internal jugular vein or, rarely, into the venous angle. This vein drains blood away from the skin and muscles of the neck and occipital region. The occipital, anterior jugular and suprascapular veins flow into it.

Superior vena cava is a short thin-walled vein with a diameter of 20 to 25 mm, located in the anterior mediastinum. Its length on average varies from five to eight centimeters. The superior vena cava refers to the veins of the systemic circulation and is formed by the fusion of two (left and right) brachiocephalic veins. It collects venous blood from the head, upper chest, neck, and arms and flows into the right atrium. The only inflow of the superior vena cava is the azygos vein. Unlike many other veins, this vessel has no valves.

The superior vena cava is directed downward and enters the pericardial cavity at the level of the second rib, and somewhat below it flows into the right atrium.

The superior vena cava is surrounded by:

• Left - the aorta (ascending part);
• On the right is the mediastinal pleura;
• In front - the thymus (thymus gland) and the right lung (mediastinal part, covered with pleura);
• Behind - the root of the right lung (anterior surface).

Superior vena cava system

All vessels included in the superior vena cava system are located close enough to the heart, and during relaxation they are under the influence of the suction action of its chambers. They are also affected by the chest during breathing. Due to these factors, a sufficiently strong negative pressure is created in the superior vena cava system.

The main tributaries of the superior vena cava are the valveless brachiocephalic veins. They also always have very low pressure, so there is a risk of air getting in if they are injured.

The superior vena cava system consists of veins:

• Neck and head areas;
• Chest wall, as well as some veins of the abdominal walls;
• Upper shoulder girdle and upper limbs.

Venous blood from the chest wall enters the inflow of the superior vena cava - the unpaired vein, which draws blood from the intercostal veins. The azygos vein has two valves located in its mouths.

The external jugular vein is located at the level of the angle of the lower jaw under the auricle. This vein collects blood from tissues and organs located in the head and neck. The posterior ear, occipital, suprascapular and anterior jugular veins flow into the external jugular vein.

The internal jugular vein originates near the jugular foramen of the skull. This vein, together with the vagus nerve and the common carotid artery, forms a bundle of vessels and nerves in the neck, and also includes the veins of the brain, meningeal, ocular and diploic veins.

The vertebral venous plexuses, which are part of the superior vena cava system, are subdivided into internal (passing inside the spinal canal) and external (located on the surface of the vertebral bodies).

Compression syndrome of the superior vena cava

The syndrome of compression of the superior vena cava, manifested as a violation of its patency, can develop for several reasons:

• With the progression of the development of cancer. With lung cancer and lymphomas, the lymph nodes are often affected, in the immediate vicinity of which the superior vena cava passes. Also, breast cancer metastases, soft tissue sarcomas, melanoma can lead to obstruction of patency;
• Against the background of cardiovascular failure;
• With the development of a retrosternal goiter against the background of thyroid pathology;
• With the progression of some infectious diseases, such as syphilis, tuberculosis and histioplasmosis;
• In the presence of iatrogenic factors;
• With idiopathic fibrous mediastinitis.

The syndrome of compression of the superior vena cava, depending on the causes that caused it, can progress gradually or develop quickly enough. The main symptoms of the development of this syndrome include:

• Puffiness of the face;
• Cough;
• Convulsive syndrome;
• Headache;
• Nausea;
• Dizziness;
• Dysphagia;
• Change in facial features;
• Drowsiness;
• Shortness of breath;
• Fainting;
• Chest pain;
• Swelling of the veins of the chest, and in some cases of the neck and upper extremities;
• Cyanosis and congestion of the upper chest and face.

To diagnose the syndrome of compression of the superior vena cava, as a rule, X-ray is performed, which allows to identify the pathological focus, as well as to determine the boundaries and extent of its distribution. In addition, in some cases, carry out:

• Computed tomography - to obtain more accurate data on the location of the mediastinal organs;
• Phlebography - to assess the extent of the lesion focus and to carry out differential diagnosis between vascular and extravascular lesions.

After the conducted studies, taking into account the rate of progression of the pathological process, the question of drug treatment, chemotherapy or radiation therapy or surgery is being decided.

In cases where the cause of vein changes is thrombosis, thrombolytic therapy is performed, followed by the appointment of anticoagulants (for example, sodium heparin or therapeutic doses of warfarin).

21. Superior vena cava and brachiocephalic veins, their formation, topography, tributaries.

Superior vena cava (u.cdvasuperior) is a short valveless vessel with a diameter of 21-25 mm and a length of 5-8 cm, which is formed as a result of the fusion of the right and left brachiocephalic veins behind the junction of the cartilage of the I right rib with the sternum (Fig. 109). This vein follows vertically downward and at the level of the junction of the third right cartilage with the sternum flows into the right atrium. Anterior to the vein is the thymus and the pleural mediastinal part of the right lung. On the right, the mediastinal (mediastinal) pleura is adjacent to the vein, on the left is the ascending part of the aorta. The posterior wall of the superior vena cava is in contact with the anterior surface of the root of the right lung. The azygos vein flows into the superior vena cava on the right, and small mediastinal and pericardial veins on the left. The superior vena cava collects blood from three groups of veins: veins of the walls of the thoracic and partially abdominal cavities, veins of the head and neck and veins of both upper extremities, i.e. from those areas that are supplied with blood by the branches of the arch and the thoracic part of the aorta (Table 16).

Unpaired Vienna (u.azygos) is a continuation in the chest cavity right ascending lumbar vein (v. lumb & lis ascendens dextra), which passes between the muscle bundles of the right leg of the lumbar part of the diaphragm into the posterior mediastinum and on its way anastomoses with the right lumbar veins flowing into the inferior vena cava. Behind and to the left of the azygos vein are the vertebral column, the thoracic aorta and thoracic duct, and the right posterior intercostal arteries. In front of the vein lies the esophagus. At the level of IV-V thoracic vertebrae, the unpaired vein bends around the back and top of the root of the right lung, then goes forward and downward and flows into the superior vena cava. There are two valves at the mouth of the azygos vein. The semi-unpaired vein and veins of the posterior wall of the chest cavity flow into the azygos vein on its way to the superior vena cava: right top nyaya intercostal vein; posterior intercostal veins, as well as veins of the chest cavity organs: esophageal, bronchial, pericardial and mediastinal veins.

Semi-epic vein ( v . hemiazygos ), which is sometimes called the left, or small azygos, vein, thinner than the azygos vein, since only 4-5 lower left posterior intercostal veins flow into it. Semi-unpaired vein is a continuation of the left ascending lumbar vein(v. lumbdlis ascendens sinistra), passes between the muscle bundles of the left crus of the diaphragm into the posterior mediastinum, adjacent to the left surface of the thoracic vertebrae. To the right of the semi-unpaired vein is the thoracic part of the aorta, behind are the left posterior intercostal arteries. At the level of VII-X thoracic vertebrae, the semi-unpaired vein turns steeply to the right, crosses the front of the vertebral column, is located behind the aorta, esophagus and thoracic duct) and flows into the azygos vein. An accessory semi-unpaired vein running from top to bottom flows into the semi-unpaired vein(v. hemiazygos accessoria), receiving 6-7 upper intercostal veins(I- VII), as well as the esophageal and mediastinal veins. The most significant tributaries of the azygos and semi-unpaired veins are the posterior intercostal veins, each of which is connected with its anterior end to the anterior intercostal vein, an inflow of the internal thoracic vein. The presence of such vein connections creates the possibility of the outflow of venous blood from the walls of the chest cavity back into the azygos and semi-unpaired veins and forward into the internal chest veins.

Posterior intercostal veins (w. intercostdles posteriores) are located in the intercostal spaces next to the arteries of the same name (in the groove of the corresponding rib). These veins collect blood from the tissues of the walls of the chest cavity and partly of the anterior abdominal wall (lower posterior intercostal veins). A spinal vein flows into each of the posterior intercostal veins(v. dorsalis), which forms in the skin and muscles of the back, and the intervertebral vein(v. intervertebralis), formed from the veins of the external and internal vertebral plexuses. A spinal branch flows into each intervertebral vein (r.spinalis), which, along with other veins (vertebral, lumbar and sacral), is involved in the outflow of venous blood from the spinal cord.

Internal (anterior and posterior) vertebral venous plexuses (plexus venosi vertebrdles interni, anterior et post6 rior) are located inside the spinal canal (between the hard shell of the spinal cord and the periosteum) and are represented by veins that anastomose among themselves many times (Fig. 110). The plexuses extend from the foramen magnum to the apex of the sacrum. The spinal veins and spongy veins of the vertebrae flow into the internal vertebral plexuses. From these plexuses, blood flows through the intervertebral veins passing through the intervertebral foramen (next to the spinal nerves) into the azygos, semi-unpaired and accessory semi-unpaired veins. The blood from the internal plexuses also flows into external (anterior and posterior) venous vertebral plexuses (plexus venosi vertebrdles externi, anterior et posterior), which are located on the anterior surface of the vertebrae, and also braid their arcs and processes. From the external vertebral plexuses, blood flows into the posterior intercostal, lumbar and sacral veins(vv. intercostdles posteriores, lumbales et sacrales), as well as directly into the azygos, semi-unpaired and accessory semi-unpaired veins. At the level of the upper spine, the plexus veins flow into the vertebral and occipital veins(vv. vertebrdles et occipitdles).

Brachiocephalic veins (right and left) (vv. brachiocephdlicae, dextra et sinistra) valveless, are the roots of the superior vena cava. They collect blood from the organs of the head and neck and upper limbs. Each brachiocephalic vein is formed from two veins - the subclavian and internal jugular (Fig. 111).

Left brachiocephalic veinforms behind the left thoracic-clavicular joint. The vein is 5-6 cm long, follows from the place of its formation obliquely down and to the right behind the handle of the sternum and thymus. Behind this vein are the brachial trunk, the left common carotid and subclavian arteries. At the level of the cartilage of the right I rib, the left brachiocephalic vein is connected to the right vein of the same name, forming the superior vena cava.

Right brachiocephalic vein3 cm long it forms behind the right sternoclavicular joint. Then the vein descends almost vertically behind the right edge of the sternum and is adjacent to the dome of the right pleura.

Small veins from internal organs flow into each brachiocephalic vein: thymus veins (vv. Thymicae); pericardial veins (vv, pericardidcae); pericardial diaphragmatic veins (w. pericardiacophreiiicae); bronchial veins (vv. bronchidles); esophageal veins (vv. oesophagedles); mediastinal veins (vv. mediastinales) - from the lymph nodes and connective tissue of the mediastinum. The larger tributaries of the brachiocephalic veins are the lower thyroid veins (vv. Thyroidede inferiores, only 1-3), through which blood flows from unpaired thyroid plexus (plexus thyroideus impar), and the lower laryngeal vein (v. laryngea inferior), which brings blood from the larynx and anastomoses with the upper and middle thyroid veins.

Vertebral vein (v. vertebrdlis) passes along with the vertebral artery through the transverse openings of the cervical vertebrae to the brachiocephalic vein, taking on the way the veins of the internal vertebral plexuses.

Deep cervical vein (v. cervicalis profunda) starts from the external vertebral plexuses, collects blood from the muscles and fascia located in the occipital region. This vein runs behind the transverse processes of the cervical vertebrae and flows into the brachiocephalic vein near the orifice of the vertebral vein or directly into the vertebral vein.

Internal thoracic vein (v. thoracica interna) steam room, accompanies the internal thoracic artery. The roots of the internal thoracic veins are the superior epigastric vein (v. Epigastrica su-perioris) and the musculophrenic vein (v. Musculophrenica). The superior epigastric vein anastomoses in the thickness of the anterior abdominal wall with the inferior epigastric vein, which flows into the external iliac vein. The anterior intercostal veins (w. Intercostales anteriores), lying in the anterior sections of the intercostal spaces, flow into the internal thoracic vein, which anastomose with the posterior intercostal veins that flow into the azygos or semi-unpaired veins.

The highest intercostal vein (v. Intercostalis suprema), which collects blood from 3-4 upper intercostal spaces, flows into each brachiocephalic vein, right and left.