Surface book 2: Surface Book 2 specs and features

Fig. 1.3. Types of variability of the superficial veins of the lower extremities [Shevkunenko VN, 1949]. a is the type of incomplete reduction; b – type of extreme degree of reduction; c – intermediate type

If in the superficial venous system, mainly on the lower leg, the intermediate type of vein structure dominates, then for deep veins the main form is most common, which is the result of an extreme degree of reduction of the primary venous network. With this form, deep veins are represented by two equivalent trunks with a small number of anastomoses between them. With a loose form, the leg veins are multi-stemmed, with a large number of anastomoses. The intermediate form occupies a middle position. All three types of structure of the superficial venous system of the lower extremities (main, loose and intermediate) have been studied in sufficient detail and do not cause significant controversy. Much more disagreement exists in the description of the structural features of deep veins at various levels of the lower limb, especially their relationship with each other. The origins of the inferior vena cava are the veins of the foot, where they form two networks – the cutaneous venous plantar network and the cutaneous venous network of the rear of the foot. The common dorsal digital veins, which are part of the cutaneous venous network of the rear of the foot, anastomose with each other to form the cutaneous dorsal venous arch of the foot. The ends of this arc continue in the proximal direction in the form of two longitudinal venous trunks: the lateral marginal vein (v. marginalis lateralis) and the medial vein (v. marginalis medialis). The continuation of these veins on the lower leg are, respectively, the small and large saphenous veins.

On the plantar surface of the foot, a subcutaneous venous plantar arch is isolated, which anastomoses widely with the marginal veins and sends intercapitate veins into each interdigital space, which anastomose with the veins that form the dorsal arch. The deep venous system of the foot is formed from paired companion veins that accompany the arteries. These veins form two deep arches: dorsal and plantar. The superficial and deep arches are connected by numerous anastomoses. From the dorsal deep arch, the anterior tibial veins (vv. tidiales anteriores) are formed, from the plantar (vv. tidiales posteriores) – the posterior tibial veins, which receive the peroneal (vv. peroneae). Thus, the dorsal veins of the foot pass into the anterior tibial veins, and the plantar medial and lateral form the posterior tibial veins.

Only the largest veins in the foot have venous valves. Their localization and number are not constant. The superficial venous system of the foot is connected to the deep system by vessels that do not have valves. This fact is of no small importance in clinical practice, since the introduction of various drugs and contrast agents into the superficial veins of the foot in the distal direction ensures their unhindered entry into the deep venous system of the lower limb. Thanks to this anatomical feature, it is also possible to measure venous pressure in the deep veins of the foot segment by puncturing the superficial vein of the foot. According to a number of authors, there are about 50 such vessels at the level of the foot, of which 15 are located at the level of the sole.

The venous system of the lower leg is represented by three main deep collectors (anterior, posterior tibial and peroneal) and two superficial – large and small – saphenous veins. Since the main burden in the outflow from the periphery is carried by the posterior tibial veins, into which the peroneal veins drain, it is the nature of their lesion that determines the severity of the clinical manifestations of impaired venous outflow from the distal limbs.

The great saphenous vein of the lower limb (v. saphena magna), being a continuation of the medial marginal vein (v. marginalis medialis), passes to the lower leg along the anterior edge of the medial malleolus, then passes along the medial edge of the tibia and, bending around the medial condyle of the femur from behind , in the area of ​​the knee joint passes to the inner surface of the thigh.

The small saphenous vein (v. saphena parva) is a continuation of the outer marginal vein of the foot (v. marginalis lateralis). Passing behind the outer ankle and heading upward, the small saphenous vein is first located along the outer edge of the Achilles tendon, and then lies on its posterior surface, approaching the midline of the posterior surface of the leg. Usually, starting from this area, the vein is represented by one trunk, less often by two. On the border of the middle and lower thirds of the lower leg, the small saphenous vein penetrates into the thickness of the deep fascia and is located between its sheets. Having reached the popliteal fossa, it pierces a deep sheet of fascia and flows into the popliteal vein. Less commonly, the small saphenous vein, passing above the popliteal fossa, flows into the femoral vein or tributaries of the deep vein of the thigh, and sometimes ends in any tributary of the great saphenous vein. Often, in its terminal section, the vein bifurcates and flows into the deep or saphenous veins in separate trunks. In the upper third of the lower leg, the small saphenous vein forms numerous anastomoses with the system of the great saphenous vein.

Greater and lesser saphenous veins along their course have a large number of deep branches. The deep veins of the lower leg in its upper third form the popliteal vein, the sources of which are the posterior and anterior tibial veins.

Superficial veins communicate with deep veins through perforating veins or perforators (vv. perforantes). Yu. H. Loder (1803) subdivided these veins into direct ones, connecting the main trunks of the saphenous veins with deep ones, and indirect ones, providing a connection between the tributaries of the saphenous veins and the deep venous highways. Since that time, terminological confusion has persisted in the literature regarding the veins connecting the superficial and deep venous systems. R. Linton defined direct perforating veins as veins connecting superficial veins with deep ones, and communicating ones as veins connecting superficial veins with muscular ones. Often in the literature and practice, the terms “perforators” and “communicants” are considered equivalent and are used arbitrarily. In the domestic literature, it is currently generally accepted to consider direct communicating veins flowing into the main trunks of deep veins, and indirect – communicating veins connecting superficial veins with muscle tributaries of deep veins. Perforating refers to the departments of communicating veins at the level of passage (perforation) of the own fascia of the lower leg. Many authors combine the concepts of perforating and communicating veins into a single group of internal perforating veins. Starting from the surface with one or more tributaries, after confluence, the trunk of the vein passes through the fascia, flowing into a deep or muscular vein on its own or dividing into branches. In this regard, some authors distinguish several forms of communicating veins, respectively: simple, complex, atypical, branching and collecting. Other researchers believe that the perforator vein provides a directed transfer of blood from the axes of the superficial veins to the deep veins by perforating the superficial aponeurosis. The communicating vein contributes to the indifferent diffusion of blood between different axes or sections of the superficial veins into the supraaponeurotic spaces. At the same time, these veins are subdivided according to the main topographic groups – medial, lateral and posterior.

Up to 155 perforators are described in each lower extremity, called “permanent” and detected in at least 75% of studies and surgical interventions for varicose veins. The connection between the subcutaneous and deep veins is carried out mainly indirectly, that is, through the muscular veins. The number of direct communicating veins on the lower leg ranges from 3 to 10. There are much more indirect communicating veins than direct ones. Most of the perforators are located along the axes of the “power” lines. This arrangement meets the functional need. The simplest perforator vein complex is the simple Cockett vein. It contains: 1) a supraaponeurotic segment originating in the nearest axis of the superficial vein; 2) a transaponeurotic segment, perforating the superficial aponeurosis through a larger or smaller lumen, allowing in some cases to provide passage together with the vein of the arteriole and nerve branch; 3) subaponeurotic segment, very quickly ending in the nearest axis of the deep vein; 4) valve apparatus, classically including one or two supraaponeurotic valves, one or three subaponeurotic valves, an obligatory element of which is the presence of an attachment ring corresponding to the thickening of the venous wall.

The diameter of communicating veins is also variable. According to various data, normally it ranges from 0.1 to 4 mm. In pathological processes, ectasia of communicating veins can reach 7–8 mm or more. From the point of view of practical surgery, in our opinion, the classification of the French phlebological school is the most acceptable. They divide the perforating veins into minimal (1-1.5 mm), medium (2-2.5 mm) and volumetric (3-3.5 mm). The term “megavena” is used for vessels with a diameter of more than 5 mm.

Thanks to the latest anatomical, ultrasound and endoscopic studies of the venous system of the lower extremities, it has become possible to clearly recognize the venous valves, which have the appearance of a transparent veil and are able to resist the powerful hemodynamic shocks of the muscle pumps. The number, localization and orientation of the cusps of the valve structures of the veins are also quite variable. The statement that all veins connecting the superficial and deep venous systems have valves that allow blood to pass only into the depths cannot be considered absolutely reliable, since valveless perforating veins have been identified on the foot and lower leg. There are also valves in the veins of the leg, the valves of which are oriented towards the superficial veins in some cases and in the opposite direction in others. Functioning passively depending on the direction of blood flow, the valvular apparatus of the veins of the lower extremities prevents retrograde discharge of blood, protecting venules and capillaries from a sharp pressure drop during the work of the muscular-venous mechanisms of the foot, lower leg and thigh. Hence the mutual dependence of the localization and function of the valves.

Significant variability in the structure of the superficial venous network of the lower extremities is exacerbated by the discrepancy in the names of veins and the presence of a large number of eponyms, especially in the names of perforating veins. To eliminate such discrepancies and create a unified terminology for the veins of the lower extremities, the International Interdisciplinary Consensus on venous anatomical nomenclature was created in 2001 in Rome. According to him, all the veins of the lower extremities are conventionally divided into three systems:

1. Superficial veins.
2. Deep veins.
3. Perforating veins.

Superficial veins lie between the skin and the deep (muscular) fascia. At the same time, the GSV is located in its own fascial case, formed by splitting the superficial fascia. The MPV trunk is also located in its own fascial case, the outer wall of which is a superficial sheet of muscular fascia. Superficial veins drain approximately 10% of the blood from the lower extremities. Deep veins are located in spaces deeper than this muscular fascia. In addition, deep veins always accompany the arteries of the same name, which does not happen with superficial veins.

Fig. 1.24. Superficial veins of the lower extremities

Deep veins provide the main blood drainage – 90% of all blood from the lower extremities flows through them. Perforating veins perforate the deep fascia, connecting the superficial and deep veins. The term “communicant veins” is reserved for veins that connect one or another vein of the same system (i.e., either superficial to each other, or deep to each other).

Main superficial veins:

1. Great saphenous vein (GSV) — vena saphena magna, in English literature — great saphenous vein (GSV). Its source is the medial marginal vein of the foot. It goes up the medial surface of the lower leg, and then the thigh. It drains into the BV at the level of the inguinal fold. Has 10-15 valves. The superficial fascia splits into two sheets, forming a channel for the GSV and cutaneous nerves. On the thigh, the GSV trunk and its large tributaries in relation to the fascia can take three main types of mutual arrangement: – i-type, in which the GSV trunk lies entirely subfascially from the SPS to the knee joint; – h-type, in which the trunk of the GSV accompanies a large tributary located suprafascially. In a certain place, it perforates the fascia and flows into the GSV. Distal to this place, the trunk of the GSV is, as a rule, much smaller in diameter than its tributary; – s-type, extreme degree of h-type, while the trunk of the GSV is aplazed distally to the confluence of the tributary. At the same time, it seems that the trunk of the GSV at some point abruptly changes direction, perforating the fascia. The existing fascial canal is considered by many authors as a protective outer “cover” that protects the trunk of the GSV from excessive stretching when pressure increases in it.

2. Most permanent tributaries:

2.1 . Intersaphenous vein(s) [vena(e)) intersaphena(e)], in the English literature – intersaphenous vein(s) – goes (goes) along the medial surface of the leg. Connects BPV and MPV. It often has connections with the perforating veins of the medial surface of the lower leg.

2.2 . Posterior thigh circumflex vein (vena circumflexa femoris posterior) It can have its origin in the MPV, as well as the lateral venous system. It rises from the back of the thigh, wrapping around it, and drains into the GSV.

2.3 . Anterior thigh circumflex vein (vena circumflexa femoris anterior), in English literature – anteri or thigh circumflex vein. It may originate in the lateral venous system. It rises along the anterior surface of the thigh, bending around it, and drains into the GSV.

2.4 . Posterior accessory great saphenous vein (vena saphena magna accessoria posterior) This is the name of any venous segment on the thigh and lower leg, running parallel and posterior to the GSV.

2.5. Anterior accessory great saphenous vein (vena saphena magna accessoria anterior), in English literature – anterior accessory great saphenous vein. This is the name of any venous segment on the thigh and lower leg, running parallel and anterior to the GSV.

2.6. Superficial accessory great saphenous vein (vena saphena magna accessoria superficialis), in English literature – superficial accessory great saphenous vein. This is the name of any venous segment on the thigh and lower leg, running parallel to the GSV and more superficial relative to its fascial sheath.

3. Small saphenous vein (vena saphena parva), in English literature – small saphenous vein. It has its source in the external marginal vein of the foot. It rises along the posterior surface of the lower leg and flows into the popliteal vein, most often at the level of the popliteal crease. It receives the following tributaries:

3.1. Superficial accessory small saphenous vein (vena saphena parva accessoria superficialis), in English literature – superficial accessory small saphenous vein. Runs parallel to the MSV trunk above the surface sheet of its fascial sheath. Often flows into the popliteal vein on its own.

3.2. Cranial extension of the small saphenous vein (extensio cranialis venae saphenae parvae) Previously called the femoral-popliteal vein (v. femoropoplitea). It is a vestige of the embryonic intervenous anastomosis. When there is an anastomosis between this vein and the posterior femoral vein from the GSV system, it is called the vein of Giacomini.

4. Lateral venous system (systema venosa lateralis membri inferioris), in English literature – lateral ve nous system. It is located on the anterior and lateral surface of the thigh and lower leg. It is assumed that it is a vestige of the system of the lateral marginal vein that existed in the embryonic period.

5. Confluence of su perficial inguinal veins. Represents the terminal section of the GSV near the anastomosis with BS. Here, in addition to the last three tributaries listed, three fairly constant tributaries flow: the superficial epigastric vein (v. epigastrica superficialis), the external pudendal vein (v. pu denda externa) and the superficial vein surrounding the ilium (v. circumflexa ilei superficialis). In the English-language literature, there is a long-established term Crosse, which denotes this anatomical segment of the GSV with the listed tributaries.

Fig. 1.5. Perforating veins of the lateral and posterior surfaces of the lower extremities

1.6. Perforating veins of the anterior and medial surfaces of the lower extremities

Undoubtedly, only the main clinically significant venous collectors are listed and have their own names. Given the high diversity of the structure of the superficial venous network, other superficial veins not included here should be named according to their anatomical localization. Deep veins, as already mentioned, are located deeper than the muscular fascia and often accompany the arteries of the same name.

Perforating veins are one of the most numerous and diverse venous systems in form and structure. In clinical practice, they are often called by the names of the authors involved in their description. This is not only inconvenient and hard to remember, but sometimes historically not entirely correct. Therefore, in the above international consensus, it is proposed to name perforating veins according to their anatomical location.

Thus, all perforating veins of the lower extremities should be divided into 6 groups, which are divided into subgroups:

1. Perforating veins of the foot

1.1. Dorsal perforating veins of the foot

1.2. Medial perforating veins of the foot

1.3. Lateral perforating veins of the foot

1.4. Plantar perforating veins of the foot

2. Ankle perforating veins

2.1. Medial perforating veins of the ankle

2.2. Anterior perforating veins of the ankle

2.3. Lateral perforating veins of the ankle

3. Perforating veins of the leg

3. 1. Medial perforating veins of the leg

3.1.1. Paratibial perforating veins

3.1.2. Posterior tibial perforating veins

3.2. Anterior perforating veins of the leg

3.3. Lateral perforating veins of the leg

3.4. Posterior perforating veins of the leg

3.4.1. Medial gastrocnemius perforating veins

3.4.2. Lateral calf perforating veins

3.4.3. Interhead perforating veins

3.4.4. Para-Achilles perforating veins

4. Perforating veins of the knee area

4.1. Medial perforating veins of the knee joint

4.2. Suprapatellar perforating veins

4.3. Perforating veins of the lateral surface of the knee joint

4.4. Subpatellar perforating veins

4.5. Perforating veins of the popliteal fossa

5. Femoral perforating veins

5.1. Medial perforating veins of the thigh

5.1.1. Perforating veins of the adductor canal

5.1.2. Perforating veins of the groin

5.2. Perforating veins of the anterior thigh

5. 3. Perforating veins of the lateral surface of the thigh

5.4. Perforating veins of the posterior thigh

5.4.1. Perforating veins of the posteromedial thigh

5.4.2. Sciatic perforating veins

5.4.3. Perforating veins of the posterolateral thigh

5.5. Pudendal perforating veins

6. Perforating veins of the buttocks

6.1. Superior gluteal perforating veins

6.2. Middle gluteal perforating veins

6.3. Inferior gluteal perforating veins

Rzhanov A.

V. Physics of surfaces and thin films of semiconductors: a course of lectures. Part 1 (Novosibirsk, 1969)

Rzhanov A.V. Physics of surfaces and thin films of semiconductors: a course of lectures. Part 1 (Novosibirsk, 1969) – CONTENTS



Rzhanov A.V. Physics of surfaces and thin films of semiconductors: course of lectures. Part 1 (Novosibirsk, 1969) Table of contents of the book Foreword . .............................................. ...... 3 Chapter I. Phenomenological description of the semiconductor surface §1. Real semiconductor surface and surface states of electrons ................................... 8 §2. Surface layer of space charge ........ 18 §3. Surface potential barrier and work function .... 28 §4. Capacitance of the surface layer of the spatial charge and surface photo-EMF .............................. 41 §5. Surface excesses of charge carriers and surface conductivity .............................. 53 §6. Surface capture and recombination in stationary conditions ................................... 62 Conclusion ............................................... ...... 98 Table of contents ............................................... ..... 100 Continuation of the course of lectures (part 2) Rzhanov A.