Noises

Noises are heard with a stethoscope or directly by the ear at various points of the human body, both in physiological and pathological conditions. Noises are sometimes obtained on percussion (see Percussion), when shaking the patient, and when tapping certain areas. According to their place of origin, noises are divided into pulmonary, pleural, cardiac, vascular, esophageal, gastric, intestinal, peritoneal, and muscle noises. Pulmonary noises are formed both in physiological and pathological conditions. Only the character of the noises differs (see Respiratory noises, Lungs, Pneumonia, Cavity).-In physiological conditions, the displacement of pleural layers during breathing occurs without any sound phenomena. When the surface of one or both pleural layers becomes rough, either due to the deposition of fibrinous masses or extreme dryness (in cholera), the displacement of the layers causes a noise, which is determined as pleural friction noise. Pleural friction noise is sometimes heard only over a small area, sometimes it extends over a considerable distance. The character of pleural friction noise is varied. Sometimes the noise is very faint, sometimes it is rough, scraping. It can reach such an intensity that it is felt by a hand applied to the chest, and sometimes it is even heard at a distance. Pressure with the stethoscope intensifies pleural friction noise. Pleural friction noise is usually heard on both inspiration and expiration; much less frequently it is heard only on expiration or only on inspiration. When fluid and gases accumulate in the pleural cavity, and with rapid change of position, a splashing noise is heard (see Hippocrates' splashing noise). In pathological conditions, in the heart instead of tones, sound phenomena are heard, which are determined as cardiac noises. From a physical point of view, the sound phenomena heard in physiological conditions and defined as tones are also noises, and due to the great periodicity of their vibrations, heart noise is closer to a physical tone than tones. Cardiac noises are divided into intracardiac, formed in the cardiac cavities, and extracardiac-paracardiac, formed outside the cardiac cavity. Intracardiac noises arise when the conditions of blood flow through the heart openings change and are caused by two main reasons: either a change in the lumen of the heart openings-valvular noises-or acceleration of blood flow-transient, accidental noises. One of the main reasons for changes in the lumen of heart openings is damage to the valve flaps, which can cause narrowing of the openings when the valves are open or incomplete closure of the openings when the valves are closed-insufficiency. Changes in the lumen of heart openings and damage to the valve apparatus can also be congenital. Valvular noises caused by congenital or acquired damage to the valve flaps or anatomical changes in the lumen of the valve openings are called organic noises. In pathological conditions, the expansion of any of the heart cavities can cause such an increase in the lumen of the opening connecting the expanded cavity with a neighboring part of the cardiovascular system that the valve apparatus will not be enough to close the expanded opening. In these cases, they speak of relative insufficiency of the valve, since it is caused not by damage to the valve apparatus, but by expansion of the valve opening. Incomplete closure can also occur with an unchanged size of the opening and undamaged valve flaps. In physiological conditions, the valve apparatus cannot completely close the valve opening if it does not first narrow due to the contraction of the muscles surrounding the opening (see Heart, physiology). When these muscles are damaged, the preliminary narrowing of the valve opening will not occur and therefore complete closure will not result. All this group of valvular noises is called functional. In relation to noises caused by damage to the muscles surrounding the valve openings, this is incorrect, since there is often anatomical damage to these muscles.-Acceleration of blood passage through unchanged openings and normal function of the valve apparatus is the second main cause of noises. Perhaps a change in the physicochemical properties of blood plays a role in the occurrence of these noises. These noises, due to their variability and connection with the functional state of the organism, are also called functional. Such noises are often observed in anemias, and then they speak of anemic noises. In youth, cardiac noises are also explained by acceleration of blood flow. Depending on the causes that led to the appearance of noises, they can occur either during systole-systolic noises-or during diastole;-diastolic. Noises can have a character of increase-crescendo, decrease-decrescendo-or their combination, i.e., first increase and then decrease and vice versa. Noises can occupy the entire phase of the heart (systole or diastole) or part of it. Systolic noises are divided into protosystolic, mesosystolic, and prediastolic depending on whether they occupy the initial, middle, or final part of systole. Similarly, diastolic noises are divided into protodiastolic, mesodiastolic, and presystolic. The localization of various types of systolic and diastolic noises is determined in relation to the heart tones. In heart defects, depending on the nature of the damage, various types of systolic and diastolic noises are heard (see Heart defects). With expansion of the valve opening, with damage to the muscles surrounding the valve openings, and with acceleration of blood flow through the valve openings, almost exclusively systolic noises are heard (see Systolic noise). Diastolic noises in these cases (see Diastolic noise) are extremely rare. The main place of formation of extracardiac noises is the cardiac sac. The sliding of unchanged pericardial layers during heart contractions does not cause sound phenomena. When fibrinous masses (in pericarditis) or products of nitrogen exchange (in nephritis) are deposited on the surface of the pericardial layers, the pericardial layers become rough, like pleural layers, and give rise to so-called pericardial friction noise when displaced. Usually, at first, pericardial friction noise is very faint, resembles the rustling of silk, and is heard only over a small distance. Pressure with the stethoscope, especially with a pliable chest, intensifies the noise. The noise either gradually weakens and disappears or spreads over the entire surface of the heart, becomes rough, scraping, resembling the sound of rubbing new skin [new skin noise according to Collen (Collen)]. Friction noise accompanies individual phases of cardiac activity. In most cases, it is heard during systole and diastole of the ventricles, and sometimes the noise during systole is somewhat stronger. Sometimes the noise is heard only during ventricular systole. When the pericardium is damaged in the area of the atria, friction noise is also heard during atrial systole. A triple friction noise is obtained-presystolic-systolic-diastolic. Pericardial friction noise intensifies on inspiration, sometimes on expiration. The intensity of pericardial friction noise changes with a change in position, and in a sitting position the noise is stronger. Pericardial friction noise is not conducted anywhere and ceases at the place of its origin or at a short distance from it. Pericardial friction noise does not coincide with the tones, sometimes preceding, sometimes coinciding, sometimes following the tones.-When there is both effusion and gases in the pericardial cavity, the sound phenomena heard in the heart have the most varied character: sometimes splashing noise, sometimes mill wheel noise, sometimes falling drop noise, sometimes bell ringing noise. These sound phenomena are sometimes so sharp that they are heard at a considerable distance.-Besides pericardial noises in the heart area, noises synchronous with heart activity are heard, arising from friction between the costal or pulmonary pleura, on the one hand, and the mediastinal pleura, fused with the parietal layer of the pericardium, on the other-pleuro-pericardial noises. The maximum audibility of these noises is localized outside the cardiac dullness. From pericardial friction noise, pleuro-pericardial noise differs in that it is significantly weakened or disappears completely on inspiration or expiration.-To extracardiac noises also belong respiratory noises, arising during heart contraction in adjacent to the heart infiltrated areas of the lungs-cardio-pulmonary (cardiopulmonary noises). In physiological conditions, two tones are heard on the subclavian and carotid arteries: systolic and diastolic. On other arteries, sound phenomena are not heard and only with light pressure is a systolic noise heard on all large and small arteries. This noise is caused by narrowing of the arterial tube due to pressure. In pathological processes in the arterial wall, a systolic noise is heard without pressure on the vessel. In some diseases, mainly in aortic valve insufficiency, with gradual pressure of the stethoscope on the femoral artery, in addition to the normal systolic and a weak diastolic noise are heard-Du Rozier's double noise (see Du Rozier's sign). On the internal jugular vein, a characteristic buzzing noise is sometimes heard-the noise of the devil-see Bruit de diable.

Vascular noises are heard on the abdomen during pregnancy (obstetric examination, umbilical cord). The passage of food through the esophagus and its entry into the stomach causes the appearance of noises (see Swallowing noises). These noises are heard in the angle between the xiphoid process and the left costal arch or in the left interscapular space at the level of the angle of the scapula or the II rib. When the stomach contains both liquid and air, a splashing noise is obtained by tapping it with short, jerky blows. A splashing noise with a metallic tint is obtained with sharp movements in a patient with accumulation of liquid and gases in the abdominal cavity in cases of perforative peritonitis. With intensified intestinal movements, intestinal noises are heard. These noises can reach great intensity and in the form of rumbling can be heard from a distance. In the presence of fibrinous deposits on the surface of the peritoneum, a friction noise is felt at various points of the abdomen, mainly in the area of the liver and spleen. Fibrillar contractions of muscles produce muscle noises, which can sometimes simulate the noises heard in the lungs and heart.