Where are the veins located in humans? Anatomy of the vessels of the lower extremities: features and important nuances. Diseases of the veins of the lower extremities

The arterial, capillary and venous network is an element of the circulatory system and performs several functions that are significant for the body. Thanks to it, oxygen and nutrients are delivered to organs and tissues, gas exchange, as well as the disposal of “waste” material.

Anatomy of blood vessels lower limbs is of great interest to scientists because it allows them to predict the course of a particular disease. Every practicing doctor should know it. You will learn about the features of the arteries and veins that supply the legs from our review and video in this article.

How are the legs supplied with blood?

Depending on the structural features and functions performed, all vessels can be divided into arteries, veins and capillaries.

Arteries are hollow tubular formations that carry blood from the heart to peripheral tissues.

Morphologically they consist of three layers:

external – loose tissue with feeding vessels and nerves;
medium, made of muscle cells, as well as elastin and collagen fibers;
internal (intima), which is represented by endothelium, consisting of cells squamous epithelium, and subendothelium (loose connective tissue).

Depending on the structure of the middle layer medical instructions distinguishes three types of arteries.

Table 1: Classification arterial vessels:

Veins are made in the form of tubes with thin walls that have the property of stretching. This feature in terms of physiological conditions is quite limited by a dense frame. It has collagen and reticulin fibers. The lower limbs of a person are saturated with three venous systems. These are the superficial, deep and perforating vein system. A greater outflow of blood, namely 85-90%, occurs through the deep venous system. The volume of blood located in the superficial veins is 10-15%.

Those veins of the lower extremities that are on the surface lie in the layer of subcutaneous tissue and form connections with each other and with the deep veins. Venous system, lying on the surface, includes two saphenous veins.

The great saphenous vein is one of the longest veins present in the human body. It is equipped with several pairs of valves. The diameter of this vein ranges from 3 to 5 mm. Valves on the big one saphenous vein bivalve. Depending on the level of functional load, valves are distributed in one or another vascular segment. The leaflets of the venous valves are formed by a connective tissue base, the frame of which is expressed by a spur of the internal elastic membrane.

The valve leaf has two surfaces. Each of them is tightly wrapped in endothelium. They originate in front of the middle ankle, which belongs to the foot, and then continue their movement to subcutaneous tissue and inguinal fold. At this point it unites with the femoral vein. There are cases when the large saphenous veins, located on the thigh and, accordingly, the lower leg, are expressed by several trunks. This vein includes a huge number of tributaries that take blood fluid from the lower extremities, the external genital organs, and the frontal wall of the peritoneum, as well as the skin and tissue of the buttocks area.

The small saphenous vein is considered part of the lateral marginal vein related to the foot. In the area of the shin it runs along the posterior zone and inside the popliteal fossa it reaches the popliteal vein. There are cases when the vein in question goes higher than the popliteal fossa, and then enters the femoral, large saphenous vein, or even the deep vein, which is part of the thigh. Enters the small saphenous vein a large number of both cutaneous and saphenous veins, a considerable proportion of them fall here precisely in the lower region of the leg. The small saphenous vein drains blood from the lateral and at the same time posterior zone of the leg.

The veins of the lower extremities include three pairs of deep veins, namely the tibial, that is, the anterior and posterior, as well as the peroneal vein. The main load during the outflow of blood from the periphery falls on the posterior great tibial veins, into which the small tibial veins enter. Deep veins back side The feet originate in the area of the metatarsal veins of this part of our body, then the blood passes to the frontal large tibial veins. In the area almost high point In the lower leg, both great tibial veins join to create the popliteal vein. It is a small blood trunk that is formed by the union of deep veins. Along its entire path, in addition to the small saphenous vein, it admits veins knee joint, having pairs. This vein goes higher and then enters the femoropopliteal canal. This is where its name changes to femoral vein. Just above the inguinal fold it transforms into the external iliac vein, and then runs to the heart.

The venous system of the surface of the lower extremities comes into contact with the deep veins as perforators. They are venous vessels with thin walls and varied diameters. It can be either a fraction of a millimeter or two millimeters, but its length always remains the same - 15 cm. The valves in the perforators are placed in such a way that they allow blood to move from the superficial veins to the deep ones. Almost half of these foot veins are not equipped with valves, so blood can easily move from the foot to the superficial veins and also do the opposite. This feature is subject to functional load and physiological conditions. Perforating veins are divided into direct and indirect.

The straight veins of the lower extremities are vessels that unite the deep and superficial vein. There are few such veins, but they are quite large and are located in the distal areas of the limbs. Indirect perforators are considered the unifying part of any of the saphenous and muscular veins, which in turn is in contact with deep vein. Indirect veins in lower sections There are a lot of our bodies. They are, however, very small and are located in the muscle mass area. Each of the perforators mostly contacts not with the main trunk of the saphenous vein, but with any of its tributaries.

The venous and arterial network is performed in human body many important functions. For this reason, doctors note their morphological differences, which manifest themselves in different types blood flow, but the anatomy of all vessels is the same. The arteries of the lower extremities consist of three layers, external, internal and middle. The inner membrane is called “intima”.

It, in turn, is divided into two layers represented by: endothelium - it is the lining part inner surface arterial vessels consisting of flat epithelial cells and subendothelium - located under the endothelial layer. It consists of loose connective tissue. The tunica media consists of myocytes, collagen and elastin fibers. The outer shell, which is called “adventitia,” is a fibrous, loose connective tissue with vessels, nerve cells and lymphatic vascular network.

Human arterial system

The arteries of the lower extremities are blood vessels through which blood pumped by the heart is distributed to all organs and parts of the human body, including the lower extremities. Arterial vessels are also represented by arterioles. They have three-layer walls consisting of intima, media and adventitia. They have their own classification characteristics. These vessels have three varieties, which differ from each other in the structure of the middle layer. They are:

Elastic. The middle layer of these arterial vessels contains elastic fibers that withstand high blood pressure, formed in them during the release of the blood stream. They are represented by the aorta and pulmonary trunk.
Mixed. Here, in the middle layer, different numbers of elastic and myocyte fibers are combined. They are represented by the carotid, subclavian and popliteal arteries.
Muscular. The middle layer of these arteries consists of individual, circularly located myocyte fibers.

The diagram of arterial vessels according to the location of the internal ones is divided into three types, presented:

Main, providing blood flow in the lower and upper extremities.
Organs that supply blood to the internal organs of a person.
Intraorgan, having their own network, branched throughout all organs.

Vienna

Human venous system

When considering arteries, do not forget that the human circulatory system also includes venous vessels, which must be considered together with the arteries to create an overall picture. Arteries and veins have a number of differences, but still their anatomy always requires a combined consideration.

Veins are divided into two types and can be muscular or non-muscular.

Venous walls of the muscleless type contain endothelium and loose connective tissue. These veins are found in bone tissue, in internal organs, in the brain and retina.

Venous vessels of the muscular type, depending on the development of the myocyte layer, are divided into three types, and are underdeveloped, moderately developed and highly developed. The latter are located in the lower extremities, providing them with tissue nutrition.

Veins transport blood that is devoid of nutrients and oxygen, but is saturated with carbon dioxide and breakdown substances synthesized as a result metabolic processes. The blood flow passes through the limbs and organs, moving directly to the heart. Often the blood overcomes the speed and force of gravity several times less than its own. This property is ensured by the hemodynamics of the venous circulation. In arteries this process occurs differently. These differences will be discussed below. The only venous vessels that have different hemodynamics and blood properties are the umbilical and pulmonary.

Peculiarities

Let's look at some of the features of this network:

Compared to arterial vessels, venous vessels have a larger diameter.
They have an underdeveloped subendothelial layer and have fewer elastic fibers.
They have thin walls that fall off easily.
The middle layer, consisting of smooth muscle elements, is poorly developed.
The outer layer is quite pronounced.
They have a valve mechanism created by the venous wall and inner layer. The valve consists of myocyte fibers, and the internal leaflets consist of connective tissue. The outside of the valve is lined with an endothelial layer.
All venous membranes have vascular vessels.

The balance between venous and arterial blood flow is ensured due to the density of the venous networks, their big amount, venous plexuses, larger in size compared to arteries.

Net

The artery of the femoral region is located in a lacuna formed from vessels. Outdoor iliac artery is its continuation. It passes under the inguinal ligamentous apparatus, after which it passes into the adductor canal, consisting of a wide medial muscle tissue and a large adductor and membranous membrane located between them. From the adductor canal the arterial vessel exits into the popliteal cavity. The lacuna, consisting of vessels, is separated from its muscular area by the edge of the lata femoral muscular fascia in the form of a sickle. In this section passes nerve tissue, providing sensitivity to the lower limb. At the top is the inguinal ligamentous apparatus.

U femoral artery of the lower extremities there are branches represented by:

Superficial epigastric.
Surface envelope.
External genitalia.
Deep femoral.

The deep femoral arterial vessel also has a branching consisting of the lateral and medial arteries and a network of perforating arteries.

The popliteal arterial vessel begins from the adductor canal and ends in a membranous interosseous junction with two openings. In the place where the superior opening is located, the vessel is divided into anterior and posterior arterial sections. Its lower border is represented by the popliteal artery. Further, it branches into five parts, represented by arteries of the following types:

Upper lateral/middle medial, passing under the knee joint.
Inferior lateral/middle medial, passing through the knee joint.
Middle genicular artery.
Posterior artery of the tibial portion of the lower limb.

Then there are two tibial arterial vessels - posterior and anterior. The posterior one passes in the popliteal-tibia area, located between the superficial and deep muscular apparatus of the posterior part of the leg (there pass small arteries shins). Next, it passes next to the medial malleolus, near the flexor digitalis brevis. From it depart arterial vessels that bend around the fibular bone area, a fibular vessel, calcaneal and ankle branches.

The anterior arterial vessel passes close to the muscular system of the ankle. It is continued by the dorsal foot artery. Next, an anastomosis occurs with an arcuate arterial section, from which the dorsal arteries and those responsible for blood flow in the fingers depart. The interdigital spaces are a conductor for the deep arterial vessel, from which the anterior and posterior sections of the recurrent tibial arteries, the medial and lateral ankle-type arteries and muscle branches depart.

Anastomoses that help people maintain balance are represented by the calcaneal and dorsal anastomosis. The first passes between the medial and lateral arteries of the calcaneal area. The second is between the external foot and arcuate arteries. The deep arteries form a vertical type anastomosis.

Differences

How does the vascular network differ from the arterial network - these vessels have not only similarities, but also differences, about which we'll talk below.

Structure

Arterial vessels are thicker-walled. They contain a large amount of elastin. They have well-developed smooth muscles, that is, if there is no blood in them, they will not fall off. They provide fast delivery blood enriched with oxygen to all organs and limbs, thanks to the good contractility of its walls. The cells included in the wall layers allow blood to circulate through the arteries without obstruction.

They have an internal corrugated surface. They have this structure due to the fact that the vessels must withstand the pressure generated in them due to powerful blood emissions.

Venous pressure is much lower, so their walls are thinner. If there is no blood in them, then the walls collapse. Their muscle fibers have a weak contractile activity. The inside of the veins has a smooth surface. Blood flow through them is much slower.

Their thickest layer is considered to be the outer one, in the arteries - the middle one. Veins do not have elastic membranes; in arteries they are represented by internal and external sections.

Form

The arteries have a regular cylindrical shape and a round cross-section. Venous vessels have flattening and a tortuous shape. This is due to the valve system, thanks to which they can contract and expand.

Quantity

There are approximately 2 times fewer arteries in the body than veins. There are several veins for each middle artery.

Valves

Many veins have a valve system that prevents blood flow from moving through reverse side. The valves are always paired and are located across the entire length of the vessels opposite each other. Some veins do not have them. In arteries, the valve system is present only at the exit from the heart muscle.

Blood

Blood flows in veins many times more than in arteries.

Location

Arteries are located deep in the tissues. They reach the skin only in areas where the pulse can be heard. All people have approximately the same pulse zones.

Direction

Blood flows through arteries faster than through veins due to the pressure of the heart. At first the blood flow is accelerated, and then it decreases.

Venous blood flow is represented by the following factors:

The force of pressure, which depends on the blood impulses coming from the heart and arteries.
Suction force of the heart during relaxation between contractile movements.
Suction venous action during breathing.
Contractile activity of the upper and lower extremities.

Also, the blood supply is located in the so-called venous depot, represented by the portal vein, the walls of the stomach and intestines, the skin and the spleen. This blood will be pushed out of the depot in case of large blood loss or severe physical exertion.

Color

Because arterial blood contains a large number of oxygen molecules, it has a scarlet color. Venous blood is dark because it contains decay elements and carbon dioxide.

During arterial bleeding the blood flows like a fountain, and with venous, it flows in a stream. The first poses a serious danger to human life, especially if the arteries of the lower extremities are damaged.

The distinctive features of veins and arteries are:

Transportation of blood and its composition.
Different wall thicknesses, valve systems and blood flow strength.
Number and depth of location.

Veins, unlike arterial vessels, are used by doctors to draw blood and inject drugs directly into the bloodstream to treat various ailments.

Knowing anatomical features and the layout of arteries and veins not only in the lower extremities, but throughout the body, you can not only correctly provide first aid for bleeding, but also understand how blood circulates throughout the body.

Anatomy (video)

One of constituent elements circulatory system a person is a vein. Everyone who cares about their health needs to know what a vein is by definition, what its structure and functions are.

What is a vein and its anatomical features

Veins are important blood vessels that carry blood to the heart. They form a whole network that spreads throughout the body.

They are replenished with blood from the capillaries, from which it is collected and supplied back to the main engine of the body.

This movement occurs due to the suction function of the heart and the presence of negative pressure in the chest when inhalation occurs.

Anatomy includes a number of fairly simple elements that are located on three layers that perform their functions.

An important role in normal functioning valves play.

The structure of the walls of venous vessels

Knowing how this is built blood channel, becomes the key to understanding what veins are in general.

The walls of veins consist of three layers. Outside, they are surrounded by a layer of mobile and not too dense connective tissue.

Its structure allows the lower layers to receive nutrition, including from surrounding tissues. In addition, the fastening of the veins is carried out due to this layer as well.

The middle layer is muscle tissue. It is denser than the top one, so it is what forms their shape and maintains it.

Thanks to the elastic properties of this muscle tissue, veins are able to withstand pressure changes without harming their integrity.

The muscle tissue that makes up the middle layer is formed from smooth cells.

In veins that are of the muscleless type, there is no middle layer.

This is typical for veins running in the bones, meninges, eyeballs, spleen and placenta.

The inner layer is a very thin film of simple cells. It is called the endothelium.

In general, the structure of the walls is similar to the structure of the walls of arteries. The width is usually greater, and the thickness of the middle layer, which consists of muscle tissue, is, on the contrary, less.

Features and role of venous valves

Venous valves are part of the system that ensures the movement of blood in the human body.

Venous blood flows through the body against gravity. To overcome it, the muscular-venous pump comes into operation, and the valves, having filled, do not allow the incoming fluid to return back along the bed of the vessel.

It is thanks to the valves that blood moves only towards the heart.

The valve is a fold that is formed from the inner layer consisting of collagen.

They resemble pockets in their structure, which, under the influence of the gravity of the blood, close, holding it in the desired area.

Valves can have from one to three leaflets, and they are located in small and medium-sized veins. Large vessels do not have such a mechanism.

Malfunction of the valves can lead to stagnation of blood in the veins and its erratic movement. This problem causes varicose veins, thrombosis and similar diseases.

Main functions of the vein

The human venous system, the functions of which are practically invisible in everyday life unless you think about it, ensures the life of the body.

Blood, dispersed to all corners of the body, is quickly saturated with the products of all systems and carbon dioxide.

In order to bring it all out and make room for a rich useful substances blood, veins work.

In addition, hormones that are synthesized in the endocrine glands, as well as nutrients from digestive system, are distributed throughout the body also with the participation of veins.

And, of course, a vein is a blood vessel, so it is directly involved in regulating the process of blood circulation throughout the human body.

Thanks to it, every part of the body is supplied with blood during paired work with the arteries.

Structure and characteristics

The circulatory system has two circles, small and large, which have their own tasks and characteristics. The diagram of the human venous system is based precisely on this division.

Pulmonary circulation

The lesser circle is also called the pulmonary circle. Its task is to carry blood from the lungs to the left atrium.

The capillaries of the lungs have a transition to venules, which are further combined into vessels large size.

These veins go to the bronchi and parts of the lungs, and already at the entrances to the lungs (gates), they unite into large channels, of which two come out of each lung.

They do not have valves, but go, accordingly, from right lung to the right atrium, and from the left to the left.

Systemic circulation

Big circle is responsible for supplying blood to every organ and tissue area in a living body.

Top part body is attached to the superior vena cava, which at the level of the third rib flows into the right atrium.

Veins such as the jugular, subclavian, brachiocephalic and other adjacent veins supply blood here.

From the lower part of the body, blood flows into the iliac veins. Here the blood converges through the external and internal veins, which converge into the inferior vena cava at the level of the fourth lumbar vertebra.

For all organs that do not have a pair (except for the liver), blood flows through the portal vein first to the liver, and from here to the inferior vena cava.

Features of blood movement through the veins

At some stages of movement, for example, from the lower extremities, the blood in the venous canals is forced to overcome gravity, rising almost one and a half meters on average.

This occurs due to the phases of breathing when negative pressure occurs in the chest during inhalation.

Initially, the pressure in the veins located in the vicinity of chest, is close to atmospheric.

In addition, blood is pushed through contracting muscles, indirectly participating in the blood circulation process, lifting the blood upward.

Interesting video: structure of a human blood vessel

Together, the vessels that make up the jugular veins perform the most important functions in the body. Violations in their work lead to serious consequences. To exclude the occurrence of venous pathologies, you need to know more about the jugular vein and possible problems associated with it.

What it is

The jugular vein is a collection of vessels that provide blood flow from the head and neck to the venous bed under the collarbone.

The main and main functions are to prevent blood stagnation in the brain cavity. Impairment of work functions entails very serious pathological changes in organism.

Types and location

The venous vein consists of 3 independent venous channels. Accordingly, their anatomy is separate.

The veins of the head and neck, which are responsible for the correct outflow of blood from the brain cavity, are divided into 3 types. These are the anterior, external and internal jugular veins.

Internal

It is distinguished by a relatively wide trunk, compared to the other 2. In the process of pushing out blood, it easily expands and contracts, thanks to its thin walls and diameter of 20 mm. The outflow of blood in a certain amount occurs with the help of valves.

When the lumen expands, the upper bulb is formed jugular vein. This occurs at the moment when the IJV enters from the hole.

Typical anatomy diagram:

start - area jugular foramen;
localization - the skull, or rather its base;
further – its path goes down, the place of localization is in the posterior muscle, the place of attachment is the collarbone and sternum;
intersection with posterior muscle– the area of its lower and back parts;
after that the path is laid along the trajectory of the carotid artery;
a little lower it comes forward and is located in front of the carotid artery;
further along with the carotid artery and vagus nerve are directed through the expansion site;
as a result, a powerful bundle of arteries is created, the composition of which includes carotid artery and all jugular veins.

Blood enters the IJV from the tributaries of the skull, the location of which is the cranium and outside it. Comes from vessels: brain, eye, auditory.

Also suppliers are hard shell brain, or rather its sinuses.

Outdoor

Location: neck tissue. Blood is directed from the face, head and outer part of the cervical region. Perfectly visible visually when coughing, screaming or stress.

Construction scheme:

Start - bottom corner jaws;
further down the muscle that attaches the sternum and clavicle;
crosses the outer part of the muscle. The place of intersection is the area of the rear and lower part.

It has only 2 valves located in the initial and middle parts of the neck.

Front

The main task is to carry out drainage from the chin area. Location: neck, middle line.

Anatomical features:

passes along the muscle of the tongue and jaw (along the front), downwards;
Then, on both sides, the veins connect with each other, and a venous arch is formed.

Sometimes the arc of collected together as\nals forms a middle one.

Main and main functions

Responsible for executing several essential functions in organism:

ensure proper blood circulation in the cerebral sections;
after saturating the blood with oxygen, ensure its reverse outflow;
responsible for saturation nutrients;
remove toxins from the head and neck.

If the functions of a nuclear device are impaired, it is necessary to urgently identify the causes of the pathology.

Diseases and changes

The reasons for the expansion make it known about the dysfunction of the circulatory system. This situation requires an immediate solution. You should know that pathologies do not have JV age restrictions. Both adults and children suffer from them.

Phlebectasia

Careful accurate diagnosis, the result of which should be the identification of the causes of the pathology, as well as the prescription of comprehensive effective treatment.

Extensions occur:

during stagnation, due to injury to the neck, spine or ribs;
for osteochondrosis, concussion;
for ischemia, hypertension, heart failure;
at endocrine disorders;
for a long time sitting position At work;
for malignant and benign tumors.

Phlebectasis can also be caused by stress and nervous tension. With nervous excitement, pressure can increase, resulting in a loss of elasticity of the walls of blood vessels. This can lead to valve dysfunction. Therefore, phlebectasia needs to be identified early stages.

Circulation can be negatively affected by factors such as: alcohol consumption, smoking, toxins, excessive mental and physical stress.

Thrombosis

May arise due to the presence chronic disease in organism. If they are present, as a rule, blood clots form in the vessels. If a blood clot has formed, there is a possibility of its breaking off at any time, which entails blocking the vital important arteries.

Signs of thrombosis:

Sometimes painful sensations arise in the hand;
swelling of the face;
manifestation on the skin venous networks;
when turning the head there is pain in cervical spine and neck.

The result of thrombosis can be rupture of the jugular venous channels, which leads to fatal outcome.

Phlebitis and thrombophlebitis

Inflammatory change passing in mastoid process or middle ear, are called phlebitis. The cause of phlebitis and thrombophlebitis can be:

bruises, wounds;
placement of injections and catheters in violation of sterility;
hit medications into the tissue around the vessel. This can often provoke calcium chloride when it is inserted past the artery;
hit with skin infections.

Phlebitis can be uncomplicated or purulent. The treatment of the 2 pathologies is different.

Aneurysm

A rare pathology is an aneurysm. It can even occur in children early age from 2 to 7 years. The pathology has not been fully studied. It is believed that its origin comes from abnormal development the foundations of the venous bed, or rather its connective tissue. It is formed during intrauterine development of the fetus. The anomaly does not manifest itself clinically. It can only be noticed when the child cries or screams.

Symptoms of an aneurysm:

headache;
anxiety;
sleep disturbance;
fast fatiguability.

The treatment is to reset venous blood and vascular prosthetics.

Who is involved in diagnosis and treatment?

If symptoms of the disease occur, you should consult a physician. After consultation, he can refer you to see a phlebologist.

Based on the patient’s complaints, the phlebologist conducts an initial visual examination, the result of which should be the identification of clearly severe symptoms venous disease.

In addition, all patients suffering from vascular diseases must be registered with a cardiologist. Diseases of the jugular vein must be identified early stages. You should remember the possible serious consequences.