The heart is enclosed in a dense bag with a complex layered structure that envelops it on all sides and is called the pericardium. Since the main function of the organ is pumping (and it is performed by cardiomyocytes), the presence of a "cover" on the myocardium does not seem to be such an important element. In this article, we will look at which structures help the pericardial sac to perform its functions and what is the risk of their breakage. Can the "shirt" of the heart kill a person?
What is the pericardium and what function does it perform?
The pericardium is a serous (connective tissue) closed sac where the heart is located. In shape, it resembles an obliquely cut cone, the wide part of which is firmly attached to the center of the diaphragm (the boundary between the chest cavity and the abdomen, runs along the bottom of the ribs). The upper edge of the structure ends at the level of the corner of the sternum (it is felt as a slight bulge if you slide your fingers down from the fossa between the collarbones).
Structure
The wall of the pericardial sac is double, it includes:
- The outer layer (fibrous), consisting of coarse collagen fibers (in the body, these structures are used in places from which the greatest strength is required). In addition to the heart, this shell also covers the vessels connecting to it.
- The inner layer (serous, formed by a thinner plate of connective tissue). Includes two sheets:
- subject (sub-serous), consists of thin fibers of connective tissue;
- directly serous (covered with mesothelium - a layer of cells with thin outgrowths-cilia, they are able to move the liquid part of the lymph into the space between the sheets of the pericardium), includes two plates:
- parietal (grows together with the outer fibrous layer);
- internal (outer shell of the heart, grows together with the myocardium).
A pericardial gap is formed between the parietal and internal plates. It is filled with a serous fluid (similar in composition to blood, without erythrocytes and other corpuscles) fluid, which has moved due to the work of the mesothelium (15-20 ml in an adult). It plays the role of a lubricant, allowing the outer and inner layers of the pericardium to slide freely during different phases of the organ.
If the pericardial sac is affected by the inflammatory process, then the amount of contents increases. Fibrin, a special protein responsible for the formation of blood clots (being in the blood), can fall on the inner surface of the leaves. Here it forms adhesions (lumps between the plates, which stick them together and prevent them from sliding along each other).
Fluid can also accumulate in the bags (physiological expansion of the gap between the plates of the serous leaf, which is part of the inner layer). There are two of them: transverse (at the base of the heart, from above) and oblique (located on the lower side of the pericardial sac facing the diaphragm).
The pericardium is conventionally divided into several parts:
- front (adjacent to the sternum - a flat bone on the front surface to which the ribs are attached);
- lower (attached to the tendon center of the diaphragm, adjacent to the esophagus, thoracic part of the aorta, azygos vein, main bronchi);
- lateral (right and left), they are in contact with the pleura, which wraps the lungs.
Ligaments - dense bundles of connective tissue fibers that provide a stable position of the pericardium and the organ it protects in the chest cavity - extend from each of these parts to the surrounding organs. Thanks to this fixation system, the heart will not jump out of the chest, even with the highest degree of fright.
The main tasks and mechanisms for their implementation
The main functions of the pericardium and the elements involved are presented in the table.
| Task | Executive structure | Implementation mechanism |
|---|---|---|
| Fixation of the heart | Ligaments and outer (fibrous) sheath | One end of the ligament is fixed on the pericardium, the other on nearby organs: sternum, diaphragm, ribs, trachea, spine, large bronchi and aorta |
| Depreciation | Ligamentous apparatus | The dense connective tissue that forms the basis of the ligaments is able to stretch slightly and return to its original state. This ensures the reduction of external shocks (for example, in the event of a fall) |
| Fluid in the pericardial cavity | Providing sliding of the leaves, to some extent protects the heart from displacement during sharp turns | |
| Protection | Multilayer structure of the pericardial sac, pericardial fluid | Mechanical barrier for external damage. In addition, it makes it difficult to damage the myocardium and endocardium by microorganisms from the chest cavity |
| The liquid contains bactericidal substances and cells that can exhibit immunological activity (destroy the pathogen) | ||
| Prevention of overstretching of the myocardium with blood | Dense collagen fibers of connective tissue in the pericardial layers | A sufficiently rigid outer frame prevents the muscles from stretching and deforming dangerously |
| Protection of surrounding organs | Pericardial gap and fluid contained in it | The apical impulse (the movement that the acute apex of the heart makes with each contraction) works just as well as a jackhammer. As the layers of the pericardium slide along each other, they weaken the intensity and range of motion, which prevents the ribs from collapsing |
What methods are used to diagnose diseases of the pericardium?
The pericardium outlines the outer contours of the heart. Therefore, according to their changes, it is possible to assume the presence of one or another pathology of the pericardial sac.
Features of methods for diagnosing diseases of the pericardium are presented in the table.
| Diagnostic methods | Characteristic signs | ||
|---|---|---|---|
| Heart borders | Directly pericardium | Additionally | |
| Percussion (study of the nature of sound by tapping the surface of the chest with the doctor's fingers) | Expanded. Deviations from the normative anatomical landmarks by 0.5-2 cm to the sides are identified (a dull sound is heard) | Cannot be characterized | Diagnostic errors are possible due to subjective (depending on the human factor) reasons |
| Auscultation | The point of clear listening to the tones of the apex may be displaced due to the expansion of the heart boundaries | Pericardial rubbing noise is sometimes heard (due to the deposition of fibrin clots) | If fluid is present, it dampens heart sounds and makes them feel weakened. |
| Chest x-ray | Expanded. The shadow of the heart can acquire a spherical shape (when fluid accumulates in the pericardial cavity) | Petrification (calcium salt deposits) in tumor masses can be detected | Signs of tension pneumothorax can be seen (as causes of dry cardiac tamponade) |
| Ultrasound examination of the heart | Changes in the contours are clearly visible: deformation, expansion, pathological layers, traumatic injuries | It is possible to assess the thickness and clarity of the edges (change during the inflammatory and tumor process) of the pericardium, the amount and nature of the fluid between the sheets | Allows you to choose a convenient place (usually at the lowest point of accumulation) for puncture (puncture) of the cavity and evacuation (removal) of the contents |
| CT scan | Layer-by-layer reveals the relationship between the borders of the heart and organs located nearby (it is especially important when the pericardial tumor grows into adjacent tissues) | Very clearly indicates the localization of fluid accumulations, neoplasms and adhesions, which allows you to choose a therapeutic tactic | With the introduction of contrast, the vascular network of the pericardium (and tumors) can be visualized |
| Pericardial puncture | Produced according to the results of ultrasound | Feels like an obstruction when punctured | You can find out the nature of the fluid (blood, inflammatory effusion), the presence of bacteria, their sensitivity to antibiotics; remove excess fluid that interferes with the pumping function of the heart |
What are the main threats to the patient's life?
Characteristics of the dangers that are fraught with diseases of the pericardium:
| Disease | Subspecies | The essence | Danger to life |
|---|---|---|---|
| Pericardial effusion | Serous (non-infectious) | Excessive accumulation of fluid of a different nature (up to 500 ml) in the pericardial cavity | The main threat is tamponade (pressure from the outside, which does not allow enough blood to accumulate during the relaxation of the ventricles), which leads to a drop in cardiac output and death of the patient. Indirect cardiac massage is ineffective |
| Purulent (when the pathogen enters the pericardial gap and sinuses) | |||
| Fibrinous | A lot of fibrin falls on the leaves, adhesions are formed (adhesions and seals) | ||
| Hemopericardium | As a result of myocardial injury and bleeding that has opened, the heart pushes blood not into the aorta, but into the pericardial cavity, squeezing itself | ||
| Armored heart |
| Instead of liquid, granulation tissue forms in the crevice, which, during maturation, "shrinks" and compresses the heart. Then calcium is deposited, which leads to even more compaction | Germination of not only the pericardium, but also the myocardium by adhesions and a decrease in the pumping function of the organ |
| Tumors |
| Conglomerate of altered cells | Germination of vital organs (for example, large vessels) will provoke a violation of their function |
| Cysts | The most common are coelomic | Thin-walled sac-like protrusion of the pericardium | The rupture of education leads to the development of pleuropulmonary shock, reflex cardiac arrest and respiration |
Treatment methods
To cure a patient, use:
- Conservative therapy:
- antibiotics (in the presence of microorganisms in the pericardial fluid);
- anti-inflammatory drugs;
- cytostatic drugs (in the presence of a tumor).
- Operational methods:
- puncture of the pericardium (to evacuate excess fluid);
- surgical correction (excision of cysts, tumors);
- Pericardotomy (to remove excess fluid and provide access to the heart)
- pericardiectomy ("separation" - the separation of the hardened bag in the armored heart).
Conclusions
The pericardium is the sac that surrounds the heart and is made up of different layers. The main function of fibrous is protective, serous is the production of shock-absorbing fluid. The pericardial sac protects the organ from displacement, injury and the penetration of microorganisms. The main diseases of the pericardium: exudative inflammation with a different character of effusion, armored heart, tumors and cysts.
The professionalism of the doctor will help you choose the best method of treatment: conservative (using medications) or operative (minor surgery - puncture or full-fledged surgery).
