What are lymph nodes: structure, location, functions. The structure of the lymph node The structure of the node
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The human lymphatic system is directly connected to the circulatory system. It consists of lymphatic vessels of various diameters. In places where several vessels merge, lymph nodes are formed. These are important structures that perform many functions aimed at maintaining the normal state of human immunity. Enlargement and inflammation of the nodes are signs that the body has encountered a foreign agent. The latter is a virus, microorganism, fungus or pathogenic protein. In a number of diseases, lymph nodes become enlarged without signs of inflammation. A person accidentally notices a formation under his skin in the form of a dense ball. Knowing what lymph nodes look like normally and with pathology will help you figure out whether you should worry and when to see a doctor.
Location, structure and functions of lymph nodes in the human body
Every human tissue is penetrated by a network of lymphatic capillaries and ducts. The vessels that bring lymphatic fluid with a life-giving substance to an organ or part of the body are called afferents. Those that carry lymph away from the organ along with metabolic products - efferent. The latter form regional lymph nodes near the organs. In total, there are approximately fifteen such groups in the body. They are divided into two large subgroups:
- Superficial - those that can be felt and seen when magnified.
- Deep - located inside the body cavity, around the internal organs.
Depending on where the group of lymph nodes is located, it has a corresponding name. For example, occipital, sublingual, supraclavicular, inguinal, mesenteric. The quantitative norm for all lymph nodes in the human body is considered to be 600 units.
Each node consists of two parts: stroma and parenchyma. The stroma is fibrous and reticular fibers that create the framework of the node. This is a support function. The parenchyma has functional significance. It consists of various cells: lymphocytes, macrophages, neutrophils, etc. The lymph node is covered on the outside with a capsule of connective tissue, from which partitions extend inward - trabeculae. There is a depression on the surface of the assembly - a gate. Blood capillaries and nerves enter through them, which provide trophism to the node. Each lymph node has two zones:
- Cortical, in which B-lymphocytes mature and differentiate.
- The medulla is the place where T-lymphocytes are collected.
The first function of the lymph nodes and the lymphatic system as a whole is barrier-filtration. Pathological substances (antigens) that enter the body, penetrating through the mucous membranes, enter the lymph. With its current, they reach the lymph nodes, where they linger. Next, the second function is realized - immunological, or protective. Its essence consists of a series of sequential actions. First, the structure of the antigen is recognized by special cells. Depending on the type of pathogen, the signal is transmitted to B or T lymphocytes. They destroy the harmful agent by producing antibodies or releasing specific substances.
Size, shape and consistency of lymph nodes in adults, normal and pathological
The number and location of lymph nodes in the human body changes throughout life. The first characteristic by which the condition of nodes is assessed is their normal size. Normally, the lymph node is difficult to notice with the naked eye. It cannot be felt upon palpation. If a tubercle is nevertheless felt, its size should not exceed ten millimeters. The normal consistency of the lymph nodes is soft-elastic. They also sometimes talk about it - dough-like. It should be remembered that hard nodes are a sign of a pathological process in them. Normally, in adults, the lymph node has a bean-shaped shape.
With lymphadenitis and lymphadenopathy, all characteristics of the nodes change. There is an increase in size. The knot becomes dense, changes its shape from oval to round, spherical. Lymph nodes grow together and with surrounding tissues and become immobile.
How to properly examine lymph nodes
Before starting an examination of the lymph nodes, it is necessary to find out the patient’s complaints. This will help you navigate the situation. It’s not enough to know how to feel the lymph nodes. You also need to understand what their normal characteristics should be:
- They are not noticeable, or their size is less than a centimeter.
- Nodules of soft-elastic consistency.
- Not fused with surrounding tissues and with each other.
- Painless.
- The surface of the skin over them is not changed.
An important inspection rule is to start from the head and work your way down. The occipital lymph nodes are probed first. Palpation is carried out in a standing or sitting position. The patient is turned to face the researcher. With smooth movements of both hands, the area of the back of the head and behind the ears is palpated. After this, they proceed to the study of the behind-the-ear and posterior cervical nodes. They are located along the posterior surface of the sternocleidomastoid muscle. Then the submandibular nodes are palpated on both sides in parallel. The mental node is felt with the index, middle and ring fingers of one hand. When palpating the anterior cervical nodes, the patient is asked to turn his back. The nodes are located along the anterior surface of the sternocleidomastoid muscle.
The superficial lymph nodes of the body include supraclavicular, subclavian, and mesenteric. They are probed in the corresponding anatomical zones. After this, they move on to palpation of the limb nodes. Start with the axillary nodes. To do this, ask the person to raise their hands up. Place two hands, wrapped in cloth or a T-shirt of the subject, in the armpits. Then the patient lowers his hands down. In this case, you can feel enlarged lymph nodes. Nodes in the ulnar and popliteal fossae are palpated in a semi-flexed position of the limbs.
Which lymph nodes cannot be touched with your hands?
Not all nodes can be palpated normally in adults and children. Those of them that are located inside the chest and abdominal cavity, in the small pelvis, are not available for direct examination. To obtain information about them, they resort to instrumental methods.
There are several groups of lymph nodes located inside the chest. Their names and localization are presented in the table:
Radiological methods are best suited to visualize these groups of nodes. X-rays of the chest organs are performed in direct and lateral projections. The normal size of lymph nodes in the images does not exceed 0.5-1 centimeter. In case of pathology, the following symptoms are observed in the photographs:
- Focal shadows and infiltrates.
- Expansion of the roots of the lungs.
- Increase in the size of the mediastinum.
Diagnosis of pathologies of lymph nodes in the abdominal cavity, retroperitoneal space and pelvis involves the use of ultrasound. The echo signals sent by the device's sensor are reflected from the enlarged nodes and provide information about their size.
What to do if the size, shape or consistency of the lymph nodes does not correspond to the norm
In cases where the characteristics of the lymph nodes do not correspond to the parameters that should be normal in adults and children, it is necessary to analyze the situation. First of all, you should pay attention to the connection between lymphadenopathy and chronic inflammatory processes. Often an increase in the size of nodes occurs in the presence of a source of chronic infection. For example, submandibular lymph nodes enlarge with carious teeth in the oral cavity. It is necessary to treat the root cause of lymphadenopathy - the source of infection.
Acute lymphadenitis requires urgent attention to a medical facility. This is due to the fact that catarrhal inflammation, in the absence of adequate treatment, often passes into the purulent phase. Purulent lymphadenitis is dangerous for the development of complications. These include:
- An abscess is a cavity with pus that forms at the site of an inflamed lymph node.
- Phlegmon is a diffuse purulent inflammation of soft tissues.
- Sepsis is a serious complication in which the infectious agent enters the bloodstream and spreads throughout the body. In this case, secondary foci of inflammation are formed, which in the absence of timely treatment leads to death.
The danger is posed by cases where a person has persistent painless lymphadenopathy. Especially when it is not associated with the source of infection in the body. Such variants are often found in malignant neoplasms and HIV infection. The symptoms of the underlying disease come to the fore here. A characteristic feature of these pathologies is that they have almost no clinical manifestations for a long period of time. Lymphadenopathy is the only symptom.
Important! In case of persistent causeless lymphadenopathy, you should consult a doctor for advice.
The unique and natural protective system of the human body is the lymphatic system, which covers every part of our body with a shield of its tissues. It consists of lymphoid tissue, a network of lymphatic vessels and its liquid part - lymph. This barrier mechanism plays an important role in preventing the occurrence of cancerous tumors and always deserves careful study for the correct diagnosis of these dangerous tumors.
In this article, we will introduce you to the role of the lymphatic system and the changes in it that occur during the formation and metastasis of cancer.
A little anatomy
Lymph nodes are connected to each other by lymph vessels.The tissue of the lymphatic system is distributed throughout all areas of the body, even in its smallest areas, in the form of clusters of varying sizes called lymph nodes.
- Their role is to produce plasma cells and macrophages, which are protective cells.
- In addition, the reproduction and maturation of the main components of immunity - T- and B-lymphocytes - occur in the lymphoid tissue.
Lymphatic “filters” are located under the skin layer or deeper - between muscles, internal organs, in cavities and along blood vessels. They are connected to each other by a network of lymphatic vessels.
Such a vascular network begins with the thinnest capillaries, into which interstitial fluid is absorbed, washing the cells of tissues (muscle, bone, nervous, connective, etc.) and organs. This fluid enters through the lumen of the capillary walls and creates another liquid medium - lymph. The pathogenic agents that enter it - bacteria, toxic compounds, cells that have undergone mutations - are delivered to larger vessels formed by the fusion of lymphatic capillaries, and then reach the lymph nodes. Filtering into them, the lymph is neutralized by protective cells and begins to move further - into the remaining distant “collectors”.
The final collection point for almost all (3/4 of the volume of the entire lymphatic fluid of the body) lymph is the thoracic lymphatic duct. This large vessel:
- occurs in the abdominal cavity;
- penetrates into the chest;
- located behind the esophagus and aortic arch.
At the level of the VII vertebra of the cervical spinal column, it enters the neck and flows into the lumen of the internal left jugular vein or into the area of its confluence with the left subclavian vein.
What function do lymph nodes perform in cancer?
It is the lymph nodes that act as a kind of filter with active killer cancer cells that can prevent the spread of mutated cells throughout the body. If these components of the lymphatic system did not exist, then tumor cells could migrate unhindered through the lymphatic and circulatory channels, damaging tissues and organs along the way and forming metastases in them. This means that the tumor would immediately go into the very last stage IV, and the fight against cancer would be practically pointless.
It is the lymph nodes that are able to hold back for some time, thus they make it possible to gain time for its effective treatment. Oncologists have found a direct relationship between the size of the cancerous tumor and damage to the lymphatic “filters”. According to world statistics:
- with a tumor up to 2 cm in size, metastases in the lymph nodes are found in 12% of patients;
- with a tumor process up to 3 cm – in 32%;
- up to 4 cm – in 50%;
- up to 6 cm – in 65%;
- with more than 6 cm – in 90% of patients.
How and why metastases form in lymph nodes
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Almost all malignant neoplasms are capable of metastasizing, that is, spreading their cells into the lymphatic “collectors”. During tumor growth - from about stage II of the tumor process - its tissue becomes looser, and the cells are washed out by the interstitial fluid, entering the lymphatic vessels. Then, with the lymph flow, they are sent to those lymph nodes that are located closest to the tumor (i.e., to the “sentinel” nodes).
In these “filters,” some of the cancer cells are neutralized, but the other part is preserved, multiplies and forms a secondary focus of the primary tumor – metastasis. This new tumor also begins to grow, but for some period protective cells contain its spread. This means temporary localization of the cancer process for about several months or years (depending on the level of malignancy of the cancer cells).
- When this mechanism weakens, the neoplasm becomes loose and its cells spread into the outgoing lymphatic capillaries and vessels.
- Next, the tumor tissue enters a new regional lymph node. In it, the spread of a cancerous tumor is also restrained for some time, but after some period the mutated cells migrate to even larger, distant lymphatic “collectors”.
Such central lymph nodes are located in the mediastinum, retroperitoneum and along large vessels.
How the stage of the cancer process is determined depending on metastasis
One of the important criteria by which the severity of cancer is assessed is the presence of metastases in the lymph nodes. According to the international classification, this value is expressed by the letter “N” and a number indicating the number of metastases:
- I – no metastases, designated as N0;
- II – only single metastases are detected in the nearest (sentinel) lymph nodes, N1;
- III – several metastases are found in regional lymph nodes, N2;
- IV – both regional and distant lymph nodes are affected by metastases, N3.
For each type of cancer, oncologists can use a more detailed classification system, which indicates the following values: N2a, N2b, etc. When formulating Nx, the symbol “x” means that during diagnosis, no data on lesions of the lymphatic system by metastases were obtained.
What main groups of lymph nodes are of paramount importance in diagnosing cancer?
In the human body, there are a huge number of different-sized lymph nodes located everywhere - from small to large. Oncologists, guided by anatomical principles, identify precisely those group accumulations of lymphoid tissue through which cancerous tumors metastasize. In general, such “collectors” are classified into:
- subcutaneous;
- deep, i.e. localized between the muscles and in cavities - the chest, abdominal and pelvic cavities.
In the spread of the cancer process, the following groups of superficial lymph nodes are of paramount importance:
- cervical;
- axillary;
- inguinal
The deep lymph nodes include the following groups:
- intrathoracic;
- abdominal cavity;
- pelvic cavity;
- retroperitoneal.
Group of cervical lymph nodes
In the neck, lymph nodes are represented by the following groups:
- superficial – located directly under the skin;
- deep - located along the sternocleidomastoid muscles and under the fascia;
- posterior – localized behind the sternocleidomastoid muscles;
- supraclavicular - located in the depressions above the collarbones.
Metastases to the cervical lymph nodes can give rise to cancerous tumors:
- (the so-called Schnitzler metastasis, located on the left side of the neck);
- or squamous cell carcinoma of the skin on the hands;
When metastases appear at first, the cervical nodes do not change in any way in their consistency and do not increase in size. Later they become large and are defined as round or oval tumors that protrude or do not protrude above the surface of the skin. Their consistency becomes dense, and they can move to the sides to a limited extent. Typically, such enlarged lymph nodes do not cause pain, and their size can vary from 2 to 8 cm. With lymphogranulomatosis, the “filters” affected by metastases are able to unite into one conglomerate, reaching an impressive volume.
If a secondary cancerous tumor appears in the superficial cervical lymph nodes, then it protrudes above the skin and resembles a quail egg or bean. In cases where deep lymphatic “collectors” are affected, the node is not contoured, but manifests itself by the appearance of thickening or asymmetry of the neck.
Group of axillary lymph nodes
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The group of lymph nodes in the armpit area is represented by numerous accumulations of lymphoid tissue in the form of 6 groups. One of the axillary nodes is adjacent to the walls of the armpit itself, while the others are located deeper - along the nerve trunks and blood vessels.
Metastases to the axillary lymph nodes can give rise to the following cancers:
- mammary gland;
- lymphogranulomatosis;
- melanoma or squamous cell carcinoma of the skin on the hands;
- skin of the shoulder girdle and upper chest.
The first sign of damage to this group of lymph nodes by metastases is most often a discomforting sensation of a foreign object in the armpit area. In addition, some patients of the oncologist complain of pain, which occurs in cases where the metastasis is located near the nerve and the enlarged node infringes on its tissue. In some cases, the patient may experience numbness in the arm and tingling of the skin. If an enlarged lymph node begins to put pressure on the vessel, the patient may notice swelling of the arm.
When examining armpits with lymph nodes affected by cancerous tumors, their tuberosity is sometimes noted when the arm is raised up. In addition, in this area of the body, the skin is very thin and the formations that appear are easily palpable.
Group of inguinal lymph nodes
This group of natural “filters” is localized in the area of the inguinal fold, located between the lower abdomen and the upper thighs. The superficial inguinal lymph nodes are located in the subcutaneous fatty tissue, and the deep ones are located next to the femoral vessels under the fascia.
Damage to this group of lymphatic “collectors” occurs in cancerous tumors:
- external genitalia;
- non-Hodgkin's lymphomas;
- lymphogranulomatosis;
- melanoma or squamous cell cancer of the skin of the legs, groin, lumbosacral or buttock region.
Metastases in the inguinal “collectors” are manifested by the appearance of swelling of the skin, which is similar to a hernia. When a vein or trunk of the femoral nerve is compressed by an enlarged node, the patient experiences swelling of the lower limb or pain.
Group of intrathoracic lymph nodes
This group of “filters” is divided into two subgroups:
- parietal – concentrated along the pleura (parasternal, intercostal and pleural) along the inner surface of the cavity;
- visceral (or organ) – located near organs and large vessels (paraesophageal, pericardial, parabronchial).
All organ “collectors” are also divided into lymph nodes of the anterior and posterior mediastinum.
Intrathoracic lymph “filters” can be affected by the following cancers:
- esophagus;
- lungs;
- mammary gland;
- thymus gland;
- lymphomas;
- lymphogranulomatosis;
- neoplasms of the neck and head area.
Visceral “filters” of the mediastinum can be affected by advanced malignant tumors of the pelvic organs and abdominal cavity.
When intrathoracic lymph nodes are affected by metastases, the severity of symptoms depends on the size of these secondary neoplasms. The patient may experience the following symptoms:
- prolonged cough;
- feeling of difficulty moving food through the esophagus;
- pain in the chest and behind the sternum;
- voice changes (hoarseness, hoarseness);
When the superior vena cava is compressed, the patient develops cava syndrome:
- swelling of the skin in the arms and upper half of the body, tissues of the neck and head;
- dyspnea;
- signs and respiratory failure.
Group of lymph nodes of the abdominal and pelvic cavity
In the abdominal cavity, lymphatic “collectors” are located in abundance: along the vessels and intestines, in the omentum and mesentery, parietally along the peritoneum, in large quantities near the portal system of the liver and spleen.
In the pelvic cavity, such natural “filters” of lymph are localized parietally, along the iliac blood vessels, in the tissue surrounding the pelvic organs (uterus, prostate, bladder and rectum).
Cancerous tumors of such organs can spread to the group of these lymph nodes.
The lymphatic system ensures the normal functioning of the body, serving as an important part of the immune system. Lymph nodes are organs of the lymphatic system that act as a filter, cleansing the body of harmful compounds. Lymph nodes are located in all parts of the body. They can become inflamed and enlarge in response to various pathological processes occurring in the body, so anyone who is concerned about their own health should understand in more detail the features of their location and functions.
Lymph node is a peripheral organ of the lymphatic system that acts as a biological filter through which lymph flows.
Lymph nodes are located in small groups (on average 7-12 pieces) near all large veins and vital organs. There are more than 500 lymph nodes in the human body, and their exact number is a physiological feature of each organism.
Lymph nodes ensure the cleansing of lymph. This is an important organ of the immune system, which serves as a kind of repository for immune cells and antibodies produced by the body to fight various infections. Lymph (intercellular fluid) moves through the lymphatic vessels from bottom to top and passes through the lymph nodes. In them, it is freed from toxins and infections, and is also saturated with immune cells. The purified lymph then enters the general bloodstream, saturating the blood with immune cells and a number of nutrients.
Lymph nodes are located in groups, such groups are called regional.
Thus, the lymph nodes perform a vital function, providing immune support and protecting the body from various diseases. At the same time, the lymph nodes themselves are a very vulnerable organ, the work of which directly depends on the immune system. Lymph nodes react acutely to any pathological processes accompanied by a decrease in immunity, which manifests itself in diseases of the lymph nodes - lymphadenopathy and lymphadenitis.
Anatomy of lymph nodes
Lymph nodes are small formations, predominantly round, bean-shaped or oval. The structure is represented by two elements - the capsule and the internal space of the lymph node. The capsule of the node is formed from connective tissue. The structural basis of the node, hidden in the capsule, is called stroma. The internal part of the node is a complex structure of lymphoid tissue, consisting of two layers: cortical and medulla. Inside the lymph node are lymphocytes - immune cells. These cells saturate the purified lymph and then penetrate the circulatory system, providing complete immune protection for the body.
Each node is connected to afferent lymphatic vessels on one side and efferent vessels on the other. On the convex side of the node there is a valve that prevents the reverse outflow of incoming lymph, and on the concave side there is a node gate that passes into the efferent vessels.
The normal size of lymph nodes is from 5 to 10 mm. Some nodes can reach 50 mm in size, which is not a deviation from the norm. There are no exact standards, since the size of the lymph nodes is individual for everyone and is a physiological feature. The dimensions of the smallest node are less than 1 mm, the largest are more than 5 cm. On average, the size of lymph nodes in children ranges from 3 to 10 mm. Superficial lymph nodes in children and adults are large enough to be palpated; internal ones, located in the chest or abdominal cavity, rarely exceed 5-7 mm in diameter.
The lymph node has a complex structure
Functions
Lymph nodes are the filter of the human body. Lymphocytes mature in them and special antibodies are released to fight infections.
Intercellular fluid from tissues and organs is collected through the lymphatic capillaries and then enters the lymphatic vessels connected to the lymph nodes. Lymph is supplied to the node through the afferent vessels, then cleared in the node, and then exits through the efferent vessels, through which it is then supplied to the bloodstream.
Directly in the lymph nodes, this fluid is cleared of toxins and infections, saturated with lymphocytes and antibodies, and then carried into the circulatory system, supplying immune cells to the blood.
Thus, the lymph nodes perform an important barrier function, protecting the body from various infections. In addition, the protective function of lymph nodes also manifests itself against cancer cells. When cancer cells are “detected” in the lymph nodes, the body’s immune response to the pathological process is triggered.
Location of lymph nodes in the human body
Lymph nodes are located throughout the body. The exact number of lymph nodes depends on the body of a particular person, and ranges from 500 to 800. Lymph nodes are located near all important organs and systems. They form groups located along large blood vessels.
Each group has from 2-3 to 15 lymph nodes. By location, internal and external groups of lymph nodes are distinguished.
Internal ones are located near organs, for example, in the mediastinum or in the abdominal cavity. They are small in size and provide protection to internal organs. Pathologies of such lymph nodes are difficult to diagnose without special examinations.
External lymph nodes in humans are a kind of marker of the functioning of the immune system. They are easy to feel on your own, and any episodes of decreased immunity affect their size. Where exactly the lymph nodes are located should be considered in more detail.
Having understood what lymph nodes are and why they are needed, you should determine exactly where they are located. The first thing anyone concerned about their own health should know is where the external lymph nodes are located. The fact is that by disturbances in the functioning of these lymph nodes, various pathologies can be identified in a timely manner.
The peculiarity of external lymph nodes on the human body is their superficial location. In fact, they are hidden only by skin and fatty tissue, so they can be easily felt with your fingers.
Location of superficial lymph nodes on the human body:
- head and neck;
- armpits;
- groin area;
- knees.
Superficial lymph nodes in humans also include supraclavicular and ulnar. However, not all people have these nodes that can be easily felt. In addition, the cervical, axillary and inguinal lymph nodes are of greatest diagnostic importance.
Lymph nodes are present throughout the body, their number may vary
Having figured out where the external lymph nodes are located, we should take a closer look at these groups. One of the most important groups of nodes, allowing timely suspicion of various pathologies, are the cervical lymph nodes.
The structural features of the lymph nodes of the neck are such that they are the first to respond to various acute respiratory viral infections and inflammatory diseases of the ENT organs. The function of the cervical lymph nodes is to protect nearby organs from infections.
Probably everyone has noticed that during an appointment with a therapist, the doctor always feels the patient’s neck. Palpation of the lymph nodes of the neck is an important part of the physical examination, helping to identify infectious and inflammatory processes in the ENT organs and upper respiratory tract. This is due to the peculiarity of the location of the cervical lymph nodes.
The lymph nodes of the head cannot be classified as superficial, since they are not palpable during palpation, unlike the nodes located under the lower jaw and on the neck.
The following types of lymph nodes are located in this zone:
- parotid;
- behind the ear;
- posterior cervical or occipital;
- sublingual;
- submandibular;
- tonsillar;
- anterior cervical.
The parotid lymph nodes can be found by placing a fingertip on the area of skin between the temple and the auricle. You can feel these nodes yourself. BTEs are located immediately behind the auricle.
The posterior cervicals are located in the depression between the back of the head and the neck. The sublinguals are also called the submental. It is not possible to palpate this group of lymph nodes on your own, since access to them is blocked by the chin.
The submandibular are located, as the name suggests, under the lower jaw. These nodes are quite large; the size of the mandibular lymph nodes is about 4 mm. They can be felt by placing your palms on the neck, resting your fingers on the middle of the lower jaw on the right and left.
Tonsillar lymph nodes are called lymph nodes located between the angle of the lower jaw and the earlobe. The structural features of the tonsillar lymph nodes are such that they often enlarge during various acute respiratory viral infections, so palpation of this area is included in the list of necessary examinations when visiting a therapist.
The anterior cervical group of lymph nodes can be palpated independently. To do this, you need to mentally draw a straight line from your earlobe to your collarbone. Along this line in the neck area are the anterior cervical lymph nodes. The size of the cervical lymph nodes varies from person to person, but on average their diameter is 7-10 mm, which makes them easy to palpate.
Some lymph nodes are superficial and easy to feel, while others are detected only during instrumental examination
Group of axillary lymph nodes
The anatomical diagram will explain in detail how the lymph nodes are located on the human body. Knowing what the lymph nodes look like and what their functions are, the anatomy of the lymph nodes will help you understand their location.
The lymph nodes of the armpits are one of the most important groups. They are located in the fatty tissue of the axillary fossa, which ensures their easy palpation. This group of lymph nodes plays an important diagnostic role, as it allows one to identify a number of pathologies of the chest and mammary glands in the initial stages.
Note! Despite the fact that the main role of lymph nodes in the human body is to filter lymph and support the immune system, the health of these organs of the lymphatic system can tell a lot about the condition of the entire body.
To understand where the lymph nodes are located in the armpits, you should palpate the armpit. This group includes axillary (axillary) lymph nodes. Since these lymph nodes are responsible for lymphatic drainage in the mammary glands, they often increase in size and hurt before menstruation.
The axillary nodes are located in the armpit. Their sizes on average reach 10 mm, but the norm in adults can be 50 mm - it all depends on the characteristics of the individual person’s body.
Inguinal lymph nodes
Lymph nodes in the groin are also superficial. This is a fairly large group of lymph nodes located along the inguinal folds. The lymph nodes of this zone are divided into upper, middle and lower. The superior nodes are located at the bottom of the abdominal cavity. These are the largest lymph nodes in the groin; their size can reach 1-2 cm in diameter. In the middle of the inguinal fold, the middle inguinal nodes are palpated, below - the lower ones.
The number of lymph nodes in a person’s groin area varies. So, on the right there are up to 20 lymph nodes, while on the left there are usually no more than 14. The dimensions of the upper nodes are about 10-15 mm, the middle ones are about 7 mm, and the lower ones are 5 mm. At the same time, lymph nodes in the groin are larger or smaller than the average norm, which does not always indicate pathology, but may be a feature of physiology.
In humans, the inguinal lymph nodes are located superficially and are easy to palpate. Normally, palpation should not cause discomfort.
Note! The description of the nodes is normally quite vague, but they should not hurt when palpated. If the nodes increase in size and ache when pressed, this is a good reason to see a doctor.
The inguinal lymph nodes are responsible for cleansing the lymph of the pelvic area. They can increase or become inflamed due to various pathologies of the genitourinary system.
Another group of superficial lymph nodes is the popliteal. These are the largest lymph nodes on the leg, providing cleansing of the lymph passing through the lower limbs. The popliteal lymph nodes are located in the popliteal fossa. They are medium in size, about 7 mm in diameter, and can be easily felt independently.
In overweight people it is difficult and almost impossible to palpate the lymph nodes
The exact size and number of popliteal lymph nodes is uncertain. This is determined solely by the individual characteristics of the body. At the same time, in overweight people, the popliteal lymph nodes may not be palpable due to the large amount of fatty tissue in the popliteal fossa.
Chest nodes
Having figured out why lymph nodes are needed and what they are, it becomes clear that they are located throughout the body. One of the largest and most important groups of internal lymph nodes are the thoracic nodes. There are several groups here:
- mediastinal nodes;
- paratracheal (supraclavicular);
- bronchopulmonary lymph nodes.
Mediastinal nodes are also called mediastinal nodes. This is a group of lymph nodes located in the center of the chest. They serve to ensure the drainage of lymph from the respiratory organs. This group of lymph nodes is the most numerous. The dimensions of these nodes do not exceed 5 mm in diameter.
The paratracheal lymph nodes are located slightly above the clavicles. They ensure the drainage of lymph from the trachea. These nodes are small, but when they increase in size they can be easily palpated.
Bronchopulmonary are the lymph nodes of the root of the lung, as well as those located between the aorta and the pulmonary trunk. This group of lymph nodes protects the lungs from infection by filtering lymph.
Intrathoracic lymph nodes provide respiratory protection
Nodes in the abdominal cavity
Few people know what exactly the lymph nodes in the abdominal cavity are for, although this group of lymph nodes is one of the most numerous. Where they are located is difficult to figure out without a special diagram, since these nodes are hidden among the abdominal organs and therefore cannot be palpated.
It is not known exactly how many lymph nodes are located in the abdominal cavity in a person, since it depends on the characteristics of the body.
The map or diagram of the location of the abdominal lymph nodes is quite confusing. The nodes are located near the spleen, mesentery and in the iliac region. The abdominal lymph nodes also include the para-aortic nodes, which are located along the abdominal aorta.
These lymph nodes play an important role in the human body, as they provide lymph flow to the abdominal area.
Having figured out where this or that group of lymph nodes is located, and what role lymph plays in the human body, you should understand what happens in the lymph nodes and why they can enlarge.
Lymph nodes become inflamed when various infections enter the body
Lymph nodes are an important structural part of the immune system. In case of any pathologies (infections, tumors, etc.), they can increase in size, providing the body’s immune response. In some cases, enlargement of lymph nodes is a natural reaction of the body to changes occurring and does not threaten health. At the same time, in some diseases, enlarged lymph nodes may be the only symptom that allows one to suspect a pathological process. The location of lymph nodes in the human body will allow us to promptly identify which lymph nodes are enlarged in order to consult a doctor in time and detect pathology at an early stage.
Note! As a rule, with various diseases, those lymph nodes that are located closest to the pathological focus become enlarged.
Knowing why lymph nodes are needed, it becomes clear that an increase in these organs of the lymph system is an alarming signal that requires attention. There are several main reasons for enlarged lymph nodes.
Oncopathology
Malignant neoplasms do not make themselves felt for a long time. Moreover, despite the absence of specific symptoms, enlargement of the lymph nodes closest to the affected organ is quite often observed. Enlargement of the lymphatic system is associated with the immune response to cancer cells.
Thus, a seemingly causeless increase in axillary lymph nodes may indicate malignant processes in the mammary glands. Since these nodes are located superficially, the increase is visible to the naked eye, which allows for timely detection of the pathological process.
Inguinal lymph nodes can become enlarged due to cancer of the reproductive system. Tonsillar and cervical lymph nodes react to malignant processes of the throat and larynx, and mediastinal nodes react to lung cancer. Due to the peculiarities of the location of lymph nodes on the human body, enlargement of internal lymph nodes can be suspected only by indirect signs.
In addition, lymph nodes may enlarge as the cancer progresses and metastases spread. According to statistics, in 15% of malignant processes of internal organs, metastasis to the lymphatic system is observed.
Infectious diseases
As already mentioned, lymph nodes react acutely to any episodes of invasion by pathogenic agents, be they microorganisms or cancer cells. This is most often observed in infectious diseases. Moreover, even a “harmless” acute respiratory viral infection is accompanied by an enlargement of the lymph nodes, most often the tonsillar and cervical ones.
Knowing the location of lymph nodes in the human body, one should be able to promptly recognize enlarged superficial lymph nodes. The table describes which groups of lymph nodes respond to various infectious diseases.
A characteristic symptom of HIV infection is prolonged enlargement of several groups of lymph nodes. If for three weeks or more there is an increase in several superficial lymph nodes at once, and there are no other symptoms, you need to check your HIV status and consult a doctor.
Immunopathology
Lymph nodes in different parts of the body can enlarge in response to an autoimmune process that occurs in the body due to various diseases. This is typical for rheumatoid arthritis and systemic lupus erythematosus. In addition, enlarged lymph nodes often occur against the background of severe allergic reactions. Separately, the drug cause of disruption of the lymph nodes is identified. Their increase may occur due to long-term use of drugs that suppress the immune system, or in response to vaccination.
Hormonal changes
In women, lymph nodes can become enlarged due to hormonal fluctuations. Many people experience enlarged inguinal, axillary and breast lymph nodes a few days before menstruation. This is not a pathology. Enlarged lymph nodes in this case are associated with fluid retention in the body, lymph stagnation and a decrease in the level of female sex hormones. Typically, symptoms disappear on the first day of menstruation.
Knowing where lymph nodes can be located on the human body, you should pay attention to two main pathologies - lymphadenopathy and lymphadenitis.
The inflammatory reaction of the lymph nodes is a barrier function of the lymphatic system; it limits the spread of infection throughout the body
Lymphadenopathy (ICD-10 code - R59) is called enlargement of the lymph nodes. The reasons for this phenomenon are discussed in detail above. Every person encounters lymphadenopathy at least once in their life, usually against the background of ARVI. Typical symptoms:
- enlarged lymph nodes;
- general weakness;
- night sweats;
- headache;
- cough and hoarse breathing (with enlarged mediastinal nodes);
- flatulence and stomach pain (with abdominal lymphadenopathy).
Lymphadenitis (ICD-10 code L04) is inflammation of the lymph nodes. This pathology develops as a result of infection entering the lymph node. This occurs against the background of erysipelas of the epidermis, furunculosis, or when infection spreads from the affected organ. Symptoms of the disease:
- pronounced enlargement of the lymph node;
- pain syndrome;
- high body temperature;
- enlarged liver and spleen;
- symptoms of general intoxication.
With lymphadenopathy, the nodes practically do not hurt. Upon palpation, you can feel the homogeneous structure of the lymph nodes. In the case of lymphadenitis, there is severe pain, which manifests itself during palpation, squeezing the affected node with clothing, or even with sudden movements.
Lymphadenopathy is most often a secondary symptom of various diseases and cannot be treated. It goes away after the cause is eliminated. Lymphadenitis is potentially dangerous due to the development of a lymph node abscess and requires specially selected antibacterial therapy.
Dangerous disease of the lymph nodes. In ICD-10, the disease is designated by code C81. This is a malignant pathology that affects the entire lymphatic system. In the initial stages, it manifests itself as lymphadenopathy and requires complex diagnostics. As a rule, lymphoma can be suspected by characteristic changes in a blood test.
How to keep lymph nodes healthy?
There is no specific prevention of lymph node pathologies. To maintain the health of the lymphatic system, you need to:
- Healthy food;
- eliminate alcohol and smoking;
- adhere to the rules of personal hygiene;
- treat any diseases in a timely manner;
- avoid hypothermia;
- maintain immune defense at a high level.
If you discover any alarming symptom, you should consult a doctor. Only a specialist after a comprehensive examination can determine the type of disease and identify the cause of its development.
The lymph nodes- these are organs located along the lymphatic vessels. Their size is 0.5-1 cm, their shape is often round, oval or bean-shaped. They are usually located regionally, in groups. From the convex side of the node, afferent lymphatic vessels enter it, and from the opposite side, called the hilum, efferent lymphatic vessels exit. In addition, arteries and nerves enter the portal and veins exit. The total number of lymph nodes reaches 1 thousand, which is about 1% of body weight.
The lymph nodes act as an active biological filter, in which up to 99% of all foreign particles and bacteria are retained and phagocytosed.
There are nonspecific protective lymph node function due to the elimination of microbes from the lymph and specific, expressed in the immune response to antigens. These organs also perform a hematopoietic function. Although there are practically no stem cells in them, proliferation of lymphoblasts and differentiation of B-lymphocytes into plasmacytes occurs. Lymph, flowing through the lymph nodes, is enriched with lymphocytes.
Lymph node development. The rudiments of lymph nodes appear at the end of the 2nd - beginning of the 3rd month of embryogenesis in the form of accumulations of mesenchyme along the lymphatic vessels. Soon, reticular tissue is formed from the mesenchyme, which makes up the stroma of the organ. By the end of the 4th month, lymphocytes invade the anlage of the nodes and clusters are formed - primary nodules without a reproduction center. At the same time, a division of the organ into the cortex and medulla appears.
The structure of the lymph nodes. The lymph node has the following structural components: a capsule containing many collagen fibers (in the area of the gate there are also smooth myocytes in the capsule), trabeculae - connective tissue crossbars, which, anastomosing with each other, form the frame of the node, reticular tissue filling the entire space , limited by capsule and trabeculae.
In the lymph node distinguish between the peripheral cortex and the central medulla. Between these parts there is also a paracortical zone.
The cortex contains accumulations of lymphoid tissue in the form of secondary nodules. These are round formations with a diameter of up to 1 mm. The central part of the nodule is called the reproduction center, or reactive center. Here, antigen-dependent proliferation of B lymphocytes and their differentiation into plasma cell precursors occurs. In addition, at the center of reproduction are dendritic cells of bone marrow origin, which on their processes retain antigens that activate B-lymphocytes, macrophages of monocyte origin, phagocytize autoimmune B-lymphocytes dying by apoptosis, antigens and foreign particles.
Along the periphery of the secondary nodule there is a crescent-shaped crown consisting of small lymphocytes (recirculating B lymphocytes, memory B cells, immature plasma cells). At the border of the corona proliferation center, T-lymphocytes (helpers) are found, which contribute to the development of B-lymphocytes into immunoblasts. The latter migrate to the medullary cords extending from the paracortical zone and nodules into the medulla.
Lymph nodules are dynamic structures. They form and then disappear. In the process of changing the structure of lymph nodes, several stages are distinguished (formation of a light reproduction center, the appearance of a crown of small lymphocytes around the center, etc.). The period of their existence is 2-3 days.
Paracortical zone of the lymph node located on the border between the cortex and medulla. It is called the thymus-dependent zone, or T-zone, because when the thymus is removed, it disappears. In the paracortical zone, blast transformation of T-lymphocytes, their proliferation and transformation into specialized cells of the immune system take place. There are a lot of dendritic cells here. They appear as a result of migration of intraepidermal macrophages from the tissues of the body's integumentary system. They carry antigens on their surface and present them to T-lymphocytes (helpers).
Besides, in this zone there are special venules lined with cubic-shaped endothelial cells. Through the wall of these venules, T- and B-lymphocytes pass from the blood into the stroma of the lymph node.
The medulla of the lymph nodes is the site of plasma cell maturation. Together with the secondary nodules of the cortex, the medullary cords make up the thymus-independent zone, or B-zone, of the lymph nodes. In addition to B-lymphocytes and plasma cells, brain cords contain T-lymphocytes and macrophages.
Lymph flows through the lymph nodes along the sinuses - spaces containing reticular tissue, and limited by the capsule and trabeculae on one side and the nodules and medullary cords on the other. There are marginal, intermediate and portal sinuses. Lymph from the latter exits through the lymphatic vessel into the hilum area. In the lumen of the sinuses, reticular cells, macrophages, lymphocytes, and plasma cells are found.
Age-related changes in lymph nodes. With age, lymph nodes and their reproduction centers gradually disappear, the phagocytic activity of macrophages decreases, the connective tissue of trabeculae grows, and the phenomena of node atrophy and their replacement with adipose tissue develop.
Reactivity and regeneration of lymph nodes. Lymph nodes are very reactive structures. They are sensitive to the action of various damaging factors (radiation, infection, intoxication, etc.). Their regeneration is possible if the afferent and efferent lymphatic vessels and, at least partially, the reticular tissue are preserved, the proliferation of cells of which is accompanied by the colonization of stem cells and their subsequent differentiation.
Educational video of the structure of a lymph node
The structure of the lymphatic system includes: lymph, lymphatic ducts and capillaries, lymph nodes.
Lymph is a colorless liquid found in the lymphatic channel. As a participant in blood formation, lymph does not contain “representatives” of red blood, but contains lymphocytes in large quantities. The network of lymphatic capillaries, ducts and columns, branching the internal organs, maintains the tissue balance of the body. Lymph nodes are bean-shaped peripheral organs of the lymphatic system ranging in size from 0.5 to 50 mm. Acting as a natural filter, they pass lymph coming from various organs.
What does a lymph node consist of?
- In the embryonic period, the development of lymph nodes begins at 9 weeks of pregnancy. At 16 weeks, the lymph nodes are enriched with B-lymphocytes, and after 5-7 days, T-lymphocytes are infused, spreading throughout the body. Active cell division (lymphopoiesis) begins inside the lymph nodes, which continues until the end of gestation, without stopping after birth.
- External structure of the LU. Externally, the lymph nodes resemble the shape of beans or kidneys. They are a normal pink color and feel firm but not soft to the touch. Located in groups, the lymph nodes change depending on the person’s age, gender and hormonal balance; they merge with each other - replacement with connective tissue occurs. The gate of the node has a slight depression; this is where the lymph vessel exits. The surface of the lymph node is smooth, but with age segmental changes occur, and the surface becomes somewhat bumpy.
- Internal structure. The lymph node consists of a connective tissue capsule. Immediately below the capsule is the marginal sinus (gap). Trabeculae extend from the shell and deeper into the marginal sinus, which are the site of formation of macrophages. Next comes the cortex of the lymph node. There are lymphoid nodules - a cluster of B-lymphocytes. Depending on the morphological state, primary and secondary nodules are distinguished. Within these lymphoid nodules, lymph is differentiated and analyzed. In the center of the lymph node at the gate is the medulla. The cells of the medulla synthesize antibodies after receiving a signal from the nodules of the cortex.
- Principle of operation . Lymph enters special slits through the afferent vessel. First, it penetrates the marginal sinus, located between the capsule and the crossbar of the node. Then, seeping through the cortex and medulla, it is cleared of the pathogenic agents it brought: microbes, dead cell particles and tumor cells. Penetrating through the portal sinus, the lymphoid fluid enters the efferent vessels and, against the direction of gravity, slowly flows into the vena cava.
LU functions
As an important peripheral organ of blood formation, lymph nodes play an important role in the human body and perform the following functions:
- immune;
- filtration;
- barrier;
- exchange;
- protective;
- backup.
Immune (hematopoietic) function. Lymph nodes take part in the process of hematopoiesis. They form cells of the lymphoid series: lymphoblasts, prolymphocytes, lymphocytes. In addition, immunoglobulins are formed in the lymph nodes. It is also here that differentiation of lymphocytes and the formation of memory cells occurs.
Filtration function. Lymph nodes are designed in such a way that lymph, seeping between the cracks of the node, leaves foreign cells, particles, microbes and cancer cells.
Barrier function. Lingering in the lymph nodes, pathogenic objects bring the lymph nodes into a state of increased activity, as a result of which they enlarge. Thanks to this function, substances are not able to penetrate into the general lymph flow. But, for example, with cancer, in the absence of treatment, the barrier function fades, and cancer cells spread throughout the body (metastasis occurs).
Exchange function. Mesenteric lymph nodes of the intestine are involved in many metabolic processes:
- Lipid metabolism
- Digestion process
- Protein metabolism
- Vitamin-carbohydrate
Protective function. Macrophages produced by lymph nodes phagocytose (destroy) bacteria and viruses unfamiliar to the body that are carried by lymph.
Reserve function. Lymph nodes are the storage site for lymphoid fluid, which is enriched with lymphocytes.
In addition to the functions performed, a special leukocyte factor is synthesized in the lymph nodes, thanks to which proper lymphopoiesis occurs.
Groups and localizations
Lymph nodes with lymph vessels are scattered throughout the body according to a symmetrical principle. Vessels permeate all organs and systems of the human body. Lymph nodes are located inside or next to the internal secretion organs, for which they are “responsible”.
In the educational literature on human anatomy, lymph nodes, according to the principles of regionality and topography, are divided into:
- located in groups or singly along the vessels of the lymphatic system;
- somatic (parietal);
- visceral (organ);
- mixed (receive lymph from internal organs, muscles, skin, fascia).
There are about 150 groups of lymph nodes in the human body. They are characterized by species characteristics and classified by environmental properties. Clusters of lymph nodes or their single location are found in the limbs and cavities of the human body. According to nature's design, lymph nodes retain any pathogenic antigens, including cancer cells, preventing them from entering the head.
The name of lymph nodes is associated with their location.
Localization zone of the lymph node and medical name:
- Arms – elbows and armpits
- Legs – superficial inguinal and internal popliteal
- Pelvic area – internal iliac, common iliac, external iliac, sacral
- Abdominal cavity - hepatic, celiac, mesenteric, mesenteric-colic
- Chest - visceral includes the upper and lower tracheobronchial and bronchopulmonary. Parietal: intercostal and parasternal
- Mediastinum – anterior, middle and posterior mediastinal lymph nodes
- Neck – deep lateral, external (superficial) anterior cervical
- Jaw – submandibular
- Ear area – deep and superficial parotid
- Occipital
Features of enlargement and inflammation of lymph nodes in various diseases
The first thing that responds to inflammation or infection in the body is the lymph nodes. Cleared of those brought by lymph, aggressor cells accumulate in the lymph nodes, and the process of phagocytosis begins. Externally, the condition is manifested by enlarged lymph nodes, pain on palpation, low-grade fever, local hyperemia, and chills. A painful place indicates the pathology of a certain organ or system, causing illness.
Examples of diseases accompanied by enlarged lymph nodes.
Immunodeficiency virus (HIV)– slight increase in nodes in the lumbar and abdominal areas. The cervical lymph nodes increase significantly; in addition, the structure of the surface of the lymph node changes - with advanced treatment, it becomes soft and embossed. The axillary and parasternal nodes enlarge.
Venereal diseases(syphilis, gonorrhea, chlamydia, genital herpes) - manifested by inguinal lymphadenitis due to ulcers of the genital organ. Syphilis is characterized by enlargement of the superficial inguinal nodes, reaching the size of a walnut.
Tuberculosis. In the absence of treatment for Koch's bacillus, the lymph nodes become fused, forming fistulas. First of all, the chest lymph nodes become inflamed, and then the bacterial infection spreads to the back, throat, and supraclavicular nodes.
Oncological diseases. Enlargement of nodes in cancer is always observed. At the same time, in the first stages of oncology, cancerous formations are not detected in the lymph nodes. The earlier the disease is diagnosed, the greater the chances of a complete cure. occurs where exactly the attack by cancer cells occurs: lung cancer - inflammation of the thoracic nodes, stomach cancer - abdominal cavity, etc.
Gaucher and Niemann-Pick syndrome. The enlargement of nodes is associated with the accumulation of lipids and impaired fat metabolism.
If the lymph nodes are enlarged, but in the absence of pain syndromes and without abnormalities in the general blood test, one can judge about a recent infectious process. The condition is temporary and goes away without treatment. Sometimes this modification may be preceded by lymphangitis. This is inflammation of the lymphatic vessels. It manifests itself as a local infection, characterized by inflammatory processes in the arteries and veins of the extremities. The cause of inflammation can be a banal wound, combined with reduced immunity. Therapist, oncologist and infectious disease specialist are the specialists you need to contact in case of lymphadenitis.
Prevention measures
Any disease is easier to prevent than to treat. Traditional medicine can also be used as a preventive measure.
Fresh herbal collection. Lavender, elderberry, red currant leaves and calendula inflorescences are crushed and one tablespoon of the mixture is poured with boiling water (1 liter). The resulting drink is infused overnight and consumed the next day. Reception lasts up to 3 months. This collection of medicinal plants improves immunity.
Medications include taking immunomodulators, temporary use of antiviral drugs and vitamin complexes.