Collateral blood flow in the lower extremities treatment. The role of collateral circulation

The value of collateral circulation in providing compensatory processes in the vascular system of the brain is extremely high. Suffice it to say that the consequences of blockage of the cerebral arteries depend primarily on the possibilities of collateral blood supply, which in turn are determined by many factors.

A rich network of anastomoses between the arteries that supply the brain with blood opens up wide possibilities for the redistribution of blood between different areas of its vascular system. The need for this arises in both normal and pathological conditions. Normally, the anastomoses of the vascular system of the brain do not function continuously. They are mainly used to ensure blood flow to the brain pool, the blood supply of which has become insufficient due to any temporary restrictions on blood flow in the adductor vessel. So, it is known that when turning, tilting the head or extending the neck, one of the carotid or vertebral arteries is compressed predominantly. This leads to a sharp decrease in pressure in it, and after that - to the flow of blood through the arteries of the circle of Willis towards the suddenly decreased inside blood pressure. Thus, the most important basal anastomosis - the circle of Willis - acts as a blood redistributor. For this, pre-prepared paths of collateral blood supply are used.

In conditions of pathology, for example, with blockage of cerebral vessels, the role of true anastomoses immeasurably increases. The advantage of anastomoses such as the circle of Willis is that when they are turned on, a large investment of time is not required for the formation of collateral blood supply pathways. Of course, the timely activation of blood flow is the most important prerequisite for effective collateral circulation in the brain, because the time here is limited to a very short period due to the high sensitivity of nerve cells to hypoxia. The belated development of the network of collaterals in this organ is usually devoid of clinical significance, since the completion of its formation is preceded by the death of the substance of the brain. In this regard, it should be emphasized that the presence in patients of a developed network of collaterals, determined angiographically, is not yet a criterion for a full blood supply to the brain. The moment when it was formed is important, and the volume of the roundabout blood supply.

The paths and state of the collateral circulation are considered in detail by Lagore8 and Ga221 (1968).

In accordance with the structural features of the vascular system of the brain, 4 anatomical levels of collateral circulation are distinguished: one extra-

turnip and three intracranial (Fig. 9).

The extracranial level of the cerebral collateral circulation is a group of anastomoses between the systems of the carotid and subclavian-vertebral arteries. The most important of them are: anastomosis between the occipital artery (a branch of the external carotid artery) and the muscular branches of the vertebral artery, between the occipital artery and the arteries of the cervical-thyroid and costal-cervical trunks (branches of the subclavian artery), between the superior thyroid arteries (branches of the external carotid artery) and inferior thyroid arteries ("branches of the subclavian artery"). The last anastomosis also connects the systems of the carotid and subclavian arteries of both sides. Both external carotid arteries are also interconnected by the lingual and external maxillary arteries. With the help of these anastomoses, collateral circulation is carried out in case of blockage of the common carotid and vertebral arteries.

The intracranial levels of cerebral collateral circulation are represented by three groups of anastomoses: circle of Willis, anastomoses between cerebral arteries on the surface of the brain, and intracerebral vascular-capillary network.

The role of the circle of Willis as an anastomosis has been repeatedly emphasized. It remains to complete the characterization of its individual links. The anterior communicating artery plays the main and decisive role in providing blood supply to the cerebral hemisphere on the side of the blockage of the internal carotid artery or the proximal anterior cerebral artery. Through the posterior communicating arteries, blood flow occurs when the internal carotid artery is closed (especially both of these arteries), and also in the opposite direction - when the vertebral or proximal sections of the posterior cerebral arteries are closed. In general, this level is characterized by the automatic switching on of the connecting arteries when one of the main arteries of the head is switched off from the system, thereby maintaining a balanced blood supply to the cerebral hemispheres.

Anastomoses on the surface of the brain between the anterior, middle and posterior cerebral arteries provide favorable conditions for blood flow in case of blockage and, consequently, a drop in pressure in the pool of one of them, i.e., in a relatively limited area of ​​the vascular system. With insufficient blood flow through the anastomoses, foci of necrosis develop in areas that are most distant from the source of collateral blood supply. On the contrary, in case of circulatory insufficiency in the brain as a whole, the blood flow in the area of ​​the anastomoses, as in the branches most remote from the sources of blood supply, sharply decreases. The same is observed in relation to the long intracerebral arteries, plunging into the substance of the brain. In these cases, the parts of the brain that are supplied by the distal, peripheral branches of the vascular pool suffer: the zones of adjacent blood supply to the cortex, as well as the white matter of the brain.

In addition to those described above, there are a number of other anastomoses. Of these, the greatest importance when closing the internal carotid artery is given to direct intra-extra-K "ranial anastomosis of one of its branches - the ophthalmic artery with branches of the external carotid artery in the region of the corner of the eye, forehead and back of the nose. Anastomoses of the branches of the orbital, as well as the middle cerebral arteries with arteries of the dura mater. The anastomoses of the cerebellum were discussed above. They play a significant role as collaterals in the blockage of the main artery. On the surface of the brain stem and spinal cord, anastomoses are poorly represented. Therefore, the possibilities of blood redistribution are limited here. In this case, anastomoses of the intracerebral The role of anastomoses of the intracerebral vascular-capillary network as ways of collateral blood supply in other areas of the brain in case of blockage of its arteries is insignificant.

The stages in the development of collateral circulation in the large brain were revealed (IV Gannushkina, 1973). It has been established that in the basin of the closed artery, the acute stage of diffuse vasodilatation is replaced by the chronic stage of isolation of individual collateral tracts and, to a certain extent, normalization of the state of the vessels in the rest of the basin of the switched-off artery. In this case, collateral circulation of different volumes can be established from excessive perfusion to reduced blood flow. In accordance with this, there is a pronounced functional and structural restructuring of the walls of the arteries. Previously, these vascular changes were usually taken for arteritis of unknown etiology (brain form of Winivarter-Buerger's disease), while in reality they may be a secondary reaction of the arteries to changed circulatory conditions. It was also revealed that under conditions of reduced blood circulation, microemboli are formed from blood elements. The possibility of reverse development of vascular changes resulting from the transformation or slowing of blood flow (thrombosis, recalibration of arteries) and restoration of their lumen was shown.

The possibilities of developing adequate collateral circulation are determined by a number of factors. The main ones are: the state of the ways of collateral blood supply and general circulation. An important circumstance is that when the brain vessels are blocked, the process of turning on complex mechanisms to compensate for impaired blood circulation requires a certain time. Therefore, the implementation of the available possibilities of collateral circulation is to a certain extent dependent on the rate of development of occlusion. In cases with a high rate of closure of the lumen of the vessel (embolism), the development of focal changes in the brain is always observed, regardless of the level of blockage. Naturally, the scale of its consequences may be different, as they depend on many other factors.

If the rate of closure of the vessel is relatively slow, then, other things being equal, the localization and size of changes in the substance of the brain are determined by the level of damage to the arteries, in particular, the ratio of occlusion to the circle of Willis. The most unfavorable in terms of the possibilities for the development of collateral circulation is blockage of the arteries within or distal to the circle of Willis, for example, thrombosis of the intracranial part of the internal carotid artery with the spread of a thrombus to the circle of Willis, since this excludes the possibility of blood entering the vessels of the hemisphere on the side of occlusion from the vessels opposite hemisphere. Blockage of the intracranial vertebral artery within the boulevard arterial circle leads to serious consequences. The clinical picture develops rapidly in these cases and is characterized by persistent focal neurological symptoms. Patients with blockage of the intracranial carotid artery in most cases die from edema and swelling of the brain due to extensive foci of necrosis of the medulla. Bilateral blockage of the intracranial sections of the vertebral arteries is almost always fatal for patients, even in cases where their closure occurred sequentially over a long period of time. In contrast, blockage of the carotid artery outside the skull (proximal to the circle of Willis) is often asymptomatic, as is blockage of only one vertebral artery.

As for the blockage of the cerebral arteries, despite the wide network of anastomoses, the blood flow in them was considered insufficient for full-fledged collateral circulation. However, descriptions of a number of angiographically confirmed cases in which occlusion of the middle cerebral artery was accompanied by minimal neurological symptoms are increasingly being described. At the same time, angiograms show the filling of its pool with a contrast agent from the vessels of neighboring areas.

Of exceptional importance for ensuring full-fledged collateral circulation in the brain is the normal state of self-regulation mechanisms. cerebral circulation. However, in patients with vascular diseases brain often function in an unstable mode. In this regard, the dependence of cerebral blood flow on the state of general circulation and other extracerebral factors increases.

Summarizing the data on the factors that contribute to or hinder the development of sufficient compensatory circulation and thereby determine the consequences of blockage of the cerebral arteries, the following can be distinguished. First of all, these are the previously noted features of the structure of individual areas of the vascular system of the brain, both typical and individual. These may include, in addition to the peculiarities of angioarchitectonics, the number and size of anastomoses and their different distance from the areas located within the basin of the switched-off artery. Other factors are the patency of the pathways that provide collateral blood flow, as well as the level (including baseline) of systemic arterial pressure. So, if the blockage of any artery develops against the background of previous occlusion of the main vessels, then it is natural that the compensatory blood flow is limited. The significance of the rate of arterial closure and the level of systemic arterial pressure was mentioned above.

Rice. 10. Subclavian "stealing phenomenon" (diagram).

1 - right subclavian artery

2 - right vertebral artery,

3 - main artery, 4 - left vertebral artery, 5 - left subclavian artery.

Blockage of the proximal left subclavian artery. The arrows show the path of blood flow from the right vertebral artery through the main artery to the left vertebral artery and then to the left subclavian artery.

Under certain conditions, collateral circulation is carried out in physiologically unjustified forms. This peculiar mechanism of circulatory disorders in the brain occurs when the proximal branches of the aortic arch (subclavian, innominate and common carotid arteries) are blocked and is called the “steal phenomenon”. It was first described in case of blockage of the initial segment of the subclavian artery and was called "subclavian steal syndrome" "(Subclavian §1ea1 supergoshe) (Fig. 10). In this case, the vertebral artery on the side of the blockage functions in relation to the arm as a collateral through which, to the detriment of the brain, a retrograde flow of blood from the vertebrobasilar system to the arterial system of the arm occurs.When the work of the arm increases, blood flow to the brain decreases (steal), resulting in stem symptoms.

It is known that on its way the main artery gives off numerous lateral branches to supply the surrounding tissues with blood, and the lateral branches of neighboring regions are usually connected by anastomoses.

In the case of ligation of the main artery, the blood along the lateral branches of the proximal section, where high pressure, due to anastomoses, will be transferred to the lateral branches of the distal artery, going along them retrograde to the main trunk and then in the usual direction.

This is how bypass collateral arches are formed, in which they distinguish: the adductor knee, the connecting branch and the abductor knee.

adductor knee are the lateral branches of the proximal artery;

abducting knee- lateral branches of the distal artery;

connecting branch make anastomoses between these branches.

For brevity, collateral arches are often referred to simply as collaterals.

There are collaterals pre-existing And newly formed.

Preexisting collaterals are large branches, often with anatomical designations. They are included in the collateral circulation immediately after the ligation of the main trunk.

Newly formed collaterals are smaller branches, usually nameless, that provide local blood flow. They are included in the collateral circulation after 30-60 days, because. it takes a long time to open them up.

The development of collateral (roundabout) circulation is significantly influenced by a number of anatomical and functional factors.

TO anatomical factors include: the structure of collateral arches, the presence of muscle tissue, the level of ligation of the main artery.

Let's consider these factors in more detail.

· The structure of the collateral arches

It is customary to distinguish several types of collateral arches, depending on the angle at which the lateral branches depart from the main trunk, forming the adductor and abductor knees.

The most favorable conditions are created when the adductor knee departs at an acute angle, and the abductor - at a blunt one. Collateral arches in the area of ​​the elbow joint have such a structure. When dressing brachial artery at this level, gangrene almost never occurs.

All other variants of the structure of collateral arches are less advantageous. Especially for women, the type of structure of collateral arches in the region is not beneficial. knee joint, where the adductor branches depart from the popliteal artery at an obtuse angle, and the efferent branches at an acute angle.

That is why, when ligating the popliteal artery, the percentage of gangrene is impressive - 30-40 (sometimes even 70).

· The presence of muscle mass

This anatomical factor is important for two reasons:

1. The pre-existing collaterals located here are functionally beneficial, because accustomed to the so-called "play of vessels" (rather than vessels in connective tissue formations);

2. Muscles are a powerful source of newly formed collaterals.

The importance of this anatomical factor will become even more obvious if we consider the comparative figures of gangrene of the lower extremities. So, when the femoral artery is injured immediately under the pupart ligament, its ligation usually gives 25% gangrene. If the injury of this artery is accompanied by significant damage muscles, the risk of developing gangrene of the limb increases dramatically, reaching 80% or more.

artery ligation levels

They can be favorable for the development of roundabout blood circulation and unfavorable. In order to correctly navigate this issue, the surgeon must, in addition to a clear knowledge of the places where large branches depart from the main artery, have a clear idea of ​​the ways in which the roundabout blood flow develops, i.e. know the topography and severity of collateral arches at any level of the main artery.

Consider, for example, the upper limb: slide 2 - 1.4% gangrene, slide 3 - 5% gangrene. Thus, the ligation should be done inside the most pronounced collateral arches.

TO functional factors that influence the development of collaterals include: indicators of blood pressure; spasm of collaterals.

Low blood pressure with large blood loss does not contribute to sufficient collateral circulation.

Spasm of the collaterals is, unfortunately, a companion of vascular injuries, associated with irritation of the sympathetic nerve fibers located in the adventitia of the vessels.

Tasks of the surgeon when ligating vessels:

I. Consider anatomical factors

Anatomical factors can be improved, ie. influence the angles of origin of the lateral branches of the artery in order to create a favorable type of structure of the collateral arches. To this end, with incomplete damage to the artery, it must be completely crossed; it is necessary to cross the artery when ligating it throughout.

Economical excision of muscle tissue in case of PST of a wound, because muscle mass is the main source of both preexisting and newly formed collaterals.

Consider dressing levels. What is meant here?

If the surgeon has the opportunity to choose the place of ligation of the artery, then he must do this consciously, taking into account the topography and severity of the collateral arches.

If the level of ligation of the main artery is unfavorable for the development of collateral circulation, the ligature method of stopping bleeding should be abandoned in favor of other methods.

II. Influence functional factors

In order to increase blood pressure, a blood transfusion should be performed.

In order to improve the blood supply to the tissues of the limb, it was proposed to introduce 200 ml of blood into the peripheral stump of the damaged artery (Leifer, Ognev).

The introduction of a 2% solution of novocaine into the paravasal tissue, which helps to relieve spasm of the collaterals.

Mandatory intersection of the artery (or excision of its section) also helps to relieve spasm of the collaterals.

Sometimes, in order to relieve spasm of collaterals and expand their lumen, anesthesia (blockade) or removal of sympathetic ganglia is performed.

Warming the limb (with heating pads) above the level of dressing and cooling it (with ice packs) below.

This is the current understanding of collateral circulation and methods of influencing its improvement during arterial ligation.

However, in order to complete the consideration of the issue of collateral circulation, we should introduce you to another method of influencing the roundabout blood flow, which is somewhat apart from the methods outlined earlier. This method is associated with the theory of reduced blood circulation, developed and substantiated experimentally by Oppel (1906-14).

Its essence is as follows (detailed commentary on the scheme of reduced blood circulation on the codoscope).

By ligation of the vein of the same name, the volume of the arterial bed is brought into line with the venous one, some stagnation of blood is created in the limb and, thus, the degree of oxygen utilization by the tissues increases, i.e. tissue respiration improves.

So, reduced blood circulation is a blood circulation reduced in volume, but restored in the ratio (between arterial and venous).

Contraindications to the use of the method:

Diseases of the veins

Tendency to thrombophlebitis.

Currently, vein ligation according to Oppel is resorted to in cases where the ligation of the main artery leads to a sharp blanching and coldness of the limb, which indicates a sharp predominance of blood outflow over inflow, i.e. insufficiency of collateral circulation. In cases where these signs are not present, it is not necessary to ligate the vein.

Collateral circulation there 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. Its deep study, which is of great practical importance, 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 circulation of blood through the lateral vessels. It occurs under physiological conditions with temporary difficulties in blood flow (for example, when the vessels are compressed in places of movement, in the joints). It can also occur in pathological conditions - with blockage, injuries, ligation of blood vessels during operations, etc.

Under physiological conditions, the roundabout blood flow is carried out along the lateral anastomoses, which run 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.

If the blood flow through the main vessels is difficult due to their blockage, damage or ligation during operations, the blood rushes through the anastomoses to the nearest lateral vessels, which expand and become tortuous, the vascular wall is rebuilt due to changes in the muscular membrane and the elastic skeleton, 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 case of a disorder in the normal circulation caused by an obstruction in the path of blood flow in a given vessel, the existing bypass blood tracts, collaterals, are first switched on, and then new ones develop. As a result, impaired blood circulation is restored. In this process, an important role is played by nervous system(R. A. Bardina, N. I. Zotova, V. V. Kolesnikov, I. D. Lev, M. G. Prives, etc.).

From the foregoing, it is necessary to clearly define the difference between anastomoses and collaterals.

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

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

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

To understand collateral circulation, it is necessary to know those anastomoses that connect the systems of various vessels, through which collateral blood flow is established in case of vessel injuries, ligation during operations and blockage (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, as it were, separate vascular systems, are called intersystemic. Anastomoses between the branches of one large arterial highway, limited to the limits of its branching, are called intrasystemic.

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

There are anastomoses between the finest intraorgan arteries and veins - arteriovenous anastomoses. Through them, blood flows bypassing the microvasculature when it overflows and, thus, forms a collateral pathway that directly connects the arteries and veins, bypassing the capillaries.

In addition, thin arteries and veins take part in the collateral circulation, accompanying the main vessels in the neurovascular bundles and making up the so-called perivascular and perinervous arterial and venous bed(A. T. Akilova).

Anastomoses, in addition to their practical significance, are an expression of the unity arterial system, which for convenience 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 somewhat behind the ascending aorta. The superior vena cava is formed from the confluence vv. brachiocephalicae dextra et sinistra behind the junction of the 1st 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 the right atrium. With its back wall, it is in contact with a. pulmonalis dextra, separating it from the right bronchus, and for a very short distance, at the place where it flows 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 kinks through the root of the left lung). The anterior wall of the superior vena cava is separated from the anterior wall chest 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 merging 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 down and medially to the confluence with the sibling vein of the left side. In front, the right brachiocephalic vein is covered by mm. sternocleidomastoideus, sternohyoideus and sternothyreoideus, and below the cartilage of the 1st rib. The left brachiocephalic vein is approximately twice as long as the right. Having formed behind the left sternoclavicular joint, it goes behind the handle of the sternum, separated from it only by fiber and the goiter gland, to the right and downward to the confluence with the right brachiocephalic vein; while closely adhering with its lower wall to the bulge of the aortic arch, it crosses in front the left subclavian artery and the initial parts of the left common carotid artery and the 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 gland 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 cranial cavity and neck organs; starting at the foramen jugulare, in which it forms an extension, bulbus superior venae jugularis internae, the vein descends, located laterally from a. carotis interna and further down laterally from a. carotis communis. At the lower end v. jugularis internae before connecting it with v. subclavia, a second thickening is formed - bulbus inferior v. jugularis internae; in the neck above this thickening in the vein there is one or two valves. On its way to the neck, the internal jugular vein is covered by mm. sternocleidomastoideus and omohyoideus. About the sinuses pouring blood into v. jugularis interna, see the section on the brain. Here it is necessary to mention vv. ophthalmicae superior et inferior, which collect blood from the orbit and flow into the sinus cavernosus, with v. ophthalmica inferior also connects to the plexus pterygoideus (see below).

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

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

2. V. retromandibularis, retromaxillary vein, collects blood from the temporal region. Further down in v. retromandibularis, the trunk flows into it, carrying blood from the plexus pterygoideus (dense plexus between mm. pterygoidei), after which v. retromandibularis, passing through the thickness of the parotid gland together with the external carotid artery, merges with v. facialis.

The shortest path connecting the facial vein with the pterygoid plexus is the "anastomotic vein" (v. anastomotica facialis) described by M. A. Sreseli, which is located at the level of the alveolar margin of the lower jaw.

3. Vv. pharyngeae, pharyngeal veins, forming a plexus (plexus pharyngeus) on the pharynx, or pour directly into v. jugularis interna, or they fall 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 sections 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 merges 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 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 leaving at the level of the angle of the jaw from the region of the posterior jaw fossa, descends, covered with m. platysma, along the outer surface of the sternocleidomastoid muscle, crossing it obliquely downwards and backwards. Having reached the posterior edge of the sternocleidomastoid muscle, the vein enters the supraclavicular region, where it usually flows into 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, is formed from small veins above the hyoid bone, from where it descends vertically downward. Both v.v. jugulares anteriores, right and left, pierce the deep leaf of fascia colli propriae, enter spatium interaponeuroticum suprasternal and flow into the subclavian vein. In the suprasternal space, both vv. jugulares anteriores anastomose with one or two trunks. Thus, a venous arch is formed above the upper edge of the sternum and collarbones, the so-called drcus venosus jdgult. In some cases vv. jugulares anteriores are replaced by one unpaired v. jugularis anterior, which descends along the midline and merges below into the mentioned venous arch, which is 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 downward from 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 v. is formed from the confluence of these veins. brachiocephalica.

Vienna upper limb

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

Surface, or subcutaneous, veins, anastomosing with each other, form a wide-loop network, from which larger trunks separate in places. These trunks are as follows (Fig. 242):

1. V. cephalica* begins in the radial section of the rear of the hand, along the radial side of the forearm reaches the elbow, anastomosing here with v. basilica, goes along sulcus bicipitalis lateralis, then perforates the fascia and flows into v. axillaris.

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

2. V. basilica* starts on the ulnar side of the back of the hand, goes in the medial section of the anterior surface of the forearm along m. flexor carpi ulnaris to the elbow, anastomosing here with v. cephalica through v. mediana cubiti; then lies in the sulcus bicipitalis medialis, perforates the fascia on half the length of the shoulder and merges into v. brachialis.

* (Royal vein, as it was opened in diseases of the liver, which was considered the queen of the body.)

3. V. mediana cubiti, median vein of the cubital region, is an oblique anastomosis connecting v. basilica and v. cephalica. V usually flows into it. mediana antebrdchii, which carries blood from the palmar side of the hand and forearm. V. mediana ciibiti is of great practical importance, as it serves as a place for intravenous infusion of drugs, blood transfusion and taking it for laboratory research.

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

Both v.v. 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, partly covering it. Passing under the clavicle, 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(in which v. thoracoepigastrica, a large trunk of the abdominal wall, often flows), v. subscapularis, vv. circumflexae humeri.

Veins - unpaired and semi-unpaired

V. azygos, unpaired vein, And v. hemiazygos, semi-unpaired 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 the chest cavity between the muscle bundles of the legs 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 unpaired vein and through them the veins of the vertebral plexuses. Near the place where the unpaired vein bends over the root of the right lung, it takes in v. intercostdlis superior dextra, formed from the confluence 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, merges into v. azygos. It receives branches from the mediastinal organs and the lower left intercostal veins, as well as the veins of the vertebral plexuses. The upper left intercostal veins join 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 merges either into v. hemiazygos, or directly in v. azygos, bending over to the right through the anterior surface of the body of the VII thoracic vertebra.

Veins of the body walls

Vv. intercostales posteriores, posterior intercostal veins, accompany in the intercostal spaces the arteries of the same name, one vein for each artery. The confluence of the intercostal veins into the unpaired and semi-unpaired veins was mentioned above. In the posterior ends of the intercostal veins near the spine flow: ramus dorsalis (a branch that carries 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 for most of its length, however, near the I rib it merges into one trunk, which flows into v. brachiocephaiica of the same side.

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

Vertebral plexus

There are four venous vertebral plexuses - two internal and two external. 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. The veins of the spinal cord flow into the internal vertebral plexuses, 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 plexus, plexus venosi vertebrates externi, are divided in turn into two: the anterior - on the anterior surface of the vertebral bodies (developed mainly in the cervical and sacral regions), and the posterior, lying on the arches of the vertebrae, covered with deep dorsal and cervical muscles. Blood from the vertebral plexuses is poured into the trunk area through 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, 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 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 goes up and somewhat to the right, so that the farther up, the more it departs from the aorta. Below the vein is adjacent to the medial edge of the right m. psoas, then passes to its front 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 veins of the viscera.

Parietal veins: 1) vv. lumbales dextrae and sinistrae, four on each side, correspond to the arteries of the same name, receive 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.

Veins of the viscera: 1) vv. testiculares in men ( vv. ovaricae in women) begin in the testicles and braid 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 - into the left renal vein at a right angle. This last circumstance complicates, according to Girtl, the outflow of blood and causes more frequent occurrence expansion 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, go ahead 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 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; the hepatic veins carry blood out of the liver, where blood enters through the portal vein and the 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 occurs nutrients, which enter the liver through the portal vein for the neutralization and deposition of glycogen; from the pancreas, where insulin comes from, which regulates sugar metabolism; from the spleen, where the breakdown products of blood cells 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 the 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 along with the hepatic artery and ductus choledochus. Folds v. portae behind the head of the pancreas splenic vein and two mesenteric - upper and lower. Heading to the porta of the liver in the mentioned ligament of the peritoneum, it takes vv along the way. gdstricae sinistra et dextra and v. prepylorica and at the gate of the liver is 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 braid the hepatic lobules (vv. interlobulares); numerous capillaries penetrate into the lobules themselves and eventually form into vv. centrales (see "Liver"), which are collected in the hepatic veins, which flow 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 that make up the portal vein, and the second is located in the substance of the liver, where the portal vein splits into its terminal 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 takes in venous branches from small intestine(vv. intestinales), from the caecum, from the ascending colon and transverse colon (v. colica dextra et v. colica media) and, passing behind the head of the pancreas, connects to the inferior mesenteric vein. V. mesenterica inferior starts from the venous plexus of the rectum, plexus venosus rectalis. Heading up from here, on 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 only below 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 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 these tributaries are double in number outside the pelvis; when they enter the pelvis, they become solitary. In the region of the tributaries of the internal iliac vein, a number of venous plexuses are formed, anastomosing with each other.

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

2. Plexus venosus rectalis s. hemorrhoidalis (BNA) - a 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 membrane 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 corresponding arteries. The first through the inferior mesenteric vein flows 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 anus a third plexus is formed, subcutaneous - plexus subcutaneus ani, from which vv. rectales inferiores flowing into v. pudenda interna.

3. Plexus venosus vesicalis located at the bottom Bladder; through vv. vesicales, blood from this plexus drains into the internal iliac vein.

4. Plexus venosus prostaticus located between bladder and pubic fusion, covering the prostate gland and seminal vesicles in a man. Unpaired v. joins the plexus venosus prostaticus. dorsalis penis. In a woman, the dorsal vein of the penis of a man corresponds to v. dorsalis clitoridis.

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

Porto-caval and caval 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 on all its sides, namely:

1. Above, in the pars abdominalis of the esophagus - between the roots of v. gastricae sinistrae, which flows into the portal vein, and vv. esophageae flowing into vv. azygos and hemyazygos and further into 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 (tributary v. iliaca interna) et inferior (tributary v. pudenda interna), flowing into v. iliaca interna and beyond v. iliaca communis - from v. cava inferior.

3. In front, in the umbilical region, where vv. paraumbilicales, going in the thickness of lig. teres hepatis to the portal vein, v. epigastrica superior from v. cava superior (v. thoracica interna, v. brachiocephalica) and v. epigastrica inferior - from the system v. cava inferior (v. iliaca externa, v. iliaca communis).

It turns out porto-caval and caval anastomoses, which have the value of a roundabout way of outflow of blood from the portal vein system when there are obstacles for it in the liver (cirrhosis). In these cases, the veins around the umbilicus dilate and take on a characteristic appearance ("jellyfish's head") * .

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

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

5. In addition, there is a cavacaval anastomosis between the vv roots on the posterior abdominal wall. lumbales (from the v. cava inferior system), which are associated with the pair 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 pupart ligament, is called the external iliac vein. Going medially from the artery and behind it, it merges with the internal iliac vein in the region of the sacroiliac joint and forms the common iliac vein; receives two tributaries, sometimes flowing in one trunk: v. epigastric 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 pass independently of the arteries.

deep veins the feet and lower legs are double and accompany the arteries of the same name. V. poplitea, which is composed of all the deep veins of the leg, is a single trunk located in the popliteal fossa posteriorly and somewhat laterally from the artery of the same name. V. femoralis, solitary, initially located laterally from the artery of the same name, then gradually passes 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 rete venosum dorsale pedis and arcus venosus dorsalis pedis. Having received several tributaries from the side of the sole, it goes up the medial side of the lower leg and thigh. In the upper third of the thigh, it bends onto the anteromedial surface and, lying on the wide fascia, goes to the hiatus saphenus. In this place v. saphena magna flows into the femoral vein, spreading through the lower horn of the sickle-shaped edge. 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 pour partly directly into the femoral vein, partly into v. saphena magna at the place of its confluence in the region of hiatus saphenus. V. saphena parva starts on the lateral side of the dorsal surface of the foot, goes around the bottom and behind the lateral ankle and rises further along the back surface of the lower leg; first, it goes along the lateral edge of the Achilles tendon, and then upward along the middle of the posterior part of the lower leg, 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.

Clinical and topographic anatomy study such an important issue as. Collateral (roundabout) circulation exists under physiological conditions with temporary difficulties in blood flow through the main artery (for example, with compression of blood vessels in places of movement, most often in the area of ​​\u200b\u200bthe joints). Under physiological conditions, collateral circulation is carried out through existing vessels that run parallel to the main ones. These vessels are called collaterals(for example, a. collateralis ulnaris superior, etc.), hence the name of the blood flow - “ collateral circulation».

Collateral blood flow can also occur in pathological conditions - with blockage (-occlusion), partial narrowing (stenosis), damage and ligation of blood vessels. If the blood flow through the main vessels is difficult or stops, the blood rushes along the anastomoses to the nearest lateral branches, which expand, become tortuous and gradually connect (anastomose) with the existing collaterals.

In this way, collaterals exist under normal conditions and can develop again in the presence of anastomoses. Consequently, in a disorder of normal circulation caused by an obstruction in the path of blood flow in a given vessel, the existing bypass blood paths, collaterals, are first switched on, and then new ones develop. As a result, the blood bypasses the area with impaired patency of the vessel and blood circulation distal to this area is restored.

For understanding collateral circulation it is necessary to know those anastomoses that connect the systems of various vessels, along which collateral blood flow in case of their injury and bandaging or in the development of a pathological process leading to blockage of the vessel (thrombosis and embolism).

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

No less important anastomoses between systems of large veins, such as the inferior and superior vena cava, portal vein. Much attention is paid to the study of anastomoses connecting these veins (cavo-caval, porto-caval anastomoses) in clinical and topographic anatomy.

Operative surgery: lecture notes I. B. Getman

5. Collateral circulation

The term collateral circulation is understood as the flow of blood into the peripheral parts of the limb along the lateral branches and their anastomoses after the lumen of the main (main) trunk is closed. The largest ones, which take over the function of the switched off artery immediately after ligation or blockage, are referred to as the so-called anatomical or pre-existing collaterals. According to the localization of intervascular anastomoses, pre-existing collaterals can be divided into several groups: collaterals connecting the vessels of a basin of a large artery are called intrasystemic, or short paths of roundabout blood circulation. Collaterals connecting pools of different vessels (external and internal) with each other carotid arteries, the brachial artery with the arteries of the forearm, the femoral artery with the arteries of the leg), are referred to as intersystemic, or long, roundabout ways. Intraorganic connections include connections between vessels within an organ (between the arteries of adjacent lobes of the liver). Extraorganic (between the branches of the own hepatic artery in the gates of the liver, including with the arteries of the stomach). Anatomical pre-existing collaterals after ligation (or blockage by a thrombus) of the main arterial trunk take on the function of conducting blood to the peripheral parts of the limb (region, organ). At the same time, depending on the anatomical development and functional sufficiency of the collaterals, three possibilities are created for restoring blood circulation: the anastomoses are wide enough to fully ensure the blood supply to the tissues, despite the shutdown of the main artery; anastomoses are poorly developed, roundabout blood circulation does not provide nutrition peripheral departments, ischemia occurs, and then necrosis; there are anastomoses, but the volume of blood flowing through them to the periphery is small for a full blood supply, and therefore newly formed collaterals are of particular importance. The intensity of the collateral circulation depends on a number of factors: on the anatomical features of the preexisting lateral branches, the diameter of the arterial branches, the angle of their departure from the main trunk, the number of lateral branches and the type of branching, as well as on the functional state of the vessels (on the tone of their walls). For volumetric blood flow, it is very important whether the collaterals are in a spasmodic or, conversely, in a relaxed state. It is the functionality of collaterals that determines regional hemodynamics in general and the magnitude of regional peripheral resistance in particular.

To assess the sufficiency of collateral circulation, it is necessary to keep in mind the intensity of metabolic processes in the limb. Considering these factors and influencing them with the help of surgical, pharmacological and physical methods, it is possible to maintain the viability of a limb or any organ in case of functional insufficiency of pre-existing collaterals and promote the development of newly formed blood flow pathways. This can be achieved either by activating collateral circulation or by reducing tissue uptake of blood-borne nutrients and oxygen. First of all, the anatomical features of the pre-existing collaterals must be taken into account when choosing the site for applying the ligature. It is necessary to spare as much as possible the existing large lateral branches and apply a ligature as far as possible below the level of their departure from the main trunk. Of certain importance for collateral blood flow is the angle of departure of the lateral branches from the main trunk. Better conditions for blood flow are created at an acute angle of departure of the lateral branches, while an obtuse angle of discharge of the lateral vessels complicates hemodynamics, due to an increase in hemodynamic resistance. When considering the anatomical features of pre-existing collaterals, it is necessary to take into account the varying severity of anastomoses and the conditions for the development of newly formed blood flow pathways. Naturally, in those areas where there are many vascular-rich muscles, there are also the most favorable conditions for collateral blood flow and neoplasms of collaterals. It must be taken into account that when a ligature is applied to an artery, irritation of sympathetic nerve fibers, which are vasoconstrictors, occurs, and a reflex spasm of collaterals occurs, and the arteriolar link of the vascular bed is switched off from the bloodstream. Sympathetic nerve fibers run in the outer sheath of the arteries. To eliminate the reflex spasm of the collaterals and maximize the opening of the arterioles, one of the ways is to cross the artery wall along with sympathetic nerve fibers between two ligatures. Periarterial sympathectomy is also recommended. A similar effect can be achieved by introducing novocaine into the periarterial tissue or novocaine blockade of sympathetic nodes.

In addition, when the artery is crossed, due to the divergence of its ends, the direct and obtuse angles of the lateral branches are changed to an acute angle more favorable for blood flow, which reduces hemodynamic resistance and improves collateral circulation.