Pericardium

“ During the development of pericarditis the foreign body perforates the reticulum and diaphragm, passing along the middle line of the body, without which it would not come in contact with the pericardium. If the perforation, however, occurs to the right or left of the median plane, the foreign body moves forward just as easily, but it misses the pericardium and passes either into the lung, where it causes fatal pneumonia; or the pleura, where either it sets up septic pleurisy in the subpleural connective tissue or produces an abscess. ”

“ The tearing of it in any disease seems altogether unaccountable, unless we suppose an extraordinary loss of cohesion to have taken place without any mortification. The pericardium is a membrane surrounding the heart, and in a natural state contains some water, condensed from vapour after death. ”

“ There is much uncertainty in the DIAGNOSIS of partially adherent pericardium; for the friction sound may be present, the impulse normal, the heart's action unrestrained, there may be no impeded respiration, and the patient may present none of the physical signs of adhesions. Indeed, under any circumstances the diagnosis of adherent pericardium is not a very trustworthy one. More than one of the physical signs mentioned must exist to warrant anything like a positive opinion, and the disease may be latent. ”

“ Observe whether there are any adhesions between the two surfaces of the pericardium. White patches are often seen on the visceral surface of the pericardium, especially over the ventricles. These have no pathological significance and are due to slight thickenings of the pericardium.
The Heart.—Having passed the hand over the arch of the aorta and noticed whether there is any evidence of aneurism or dilatation, we grasp the heart firmly by the apex, raising and drawing it forward. ”

“ The walls of the heart become soft and flabby, and are consequently weakened; the circulation in the coronary arteries and veins is sluggish.
It is almost invariably a chronic affection, coming on insidiously, and its [p. 790] existence may not be suspected until the disorder is well advanced, when some symptom, suddenly developed, directs attention to the heart.
After death the serous pericardium is found to be opaque, somewhat thickened, and to have an anæmic appearance. The opacity is due either to interstitial deposit or to the swelling of the epithelium. ”

“ The diseases affecting the pericardium by continuity or contiguity of texture are chiefly myocarditis, tubercle of the lung and mediastinal glands, cancer of the same structures, pleurisy, pneumonia, and cancer of the oesophagus. On fibroid disease of the heart pericarditis is a frequent attendant.3 The diseases affecting the pericardium by a special election, and which are remote from the membrane, are, principally, acute articular rheumatism, Bright's disease, inflammation and other diseases of the liver, phlebitis, typhus, typhoid and eruptive fevers, scurvy, and acute alcoholism. ”

“ The pericardium supports the right heart when the weight of a long column of venous blood suddenly bears upon it, as, for example, when a man stands on his head. The abdominal viscera are slung upwards to the spine, while below they are supported by the pelvic basin and the wall of the abdomen, the muscles of which are arranged so as to act as a natural waist-band. ”

“ The two primitive aortae lie at first in the ventral wall of the 644 pericardium, but with the folding over they come to lie in the dorsal wall and gradually bulge into the cavity as they coalesce to form the heart, so that the heart drops into the dorsal side of the pericardium and draws down a fold of the membrane called the dorsal mesocardium. In mammals A. Robinson (Jour. Anat. and Phys., xxxvii. 1) has shown that no ventral mesocardium exists, though in more lowly vertebrates it is present. ”

“ The outer layer hangs loosely around the heart and is continuous with the inner layer at the top. The outer layer also connects at certain places with the membranes surrounding the lungs and is attached below to the diaphragm. Between the two layers of the pericardium is secreted a liquid which prevents friction from the movements of the heart.
Fig. 14—Diagram of section of the pericardial sac, heart removed. A. Place occupied by the heart. B. Space inside of pericardial sac. a. Inner layer of pericardium and outer lining of heart. b. Outer layer of pericardium. ”

“ The writer looks forward to the time when some accomplished yet daring surgeon, getting the right patient at the right time and in the right place, i.e., where conveniences are at hand, shall, in some case of perforating wound of the pericardium or of the heart itself, resect some portion of the anterior thoracic wall, lay open the pericardium, maintaining meanwhile artificial respiration if necessary, and suture a wound in the heart-substance, thereafter closing the pericardium and external wound, and save life which would otherwise be surely sacrificed. ”

“ This membrane closely invests the heart, supports it in its situation, prevents too great dilatation when it is gorged with blood, and too violent action when it is sometimes unduly stimulated. Notwithstanding the confinement of the pericardium, the heart, when under circumstances of unusual excitation, beats violently against the ribs, and, were it not thus tied down, would often bruise and injure itself, and cause inflammation in the neighbouring parts. ”

“ The implication of the fibrous structures of the pericardium and heart and especially of the valvular structures is a common lesion, and to be dreaded more than all others. In all animals this tendency to cardiac lesion is well marked, but especially in solipeds in which the great demands made on the heart during rapid paces, heavy draught, jumping, etc., severely strain the cardiac mechanism. ”

“ Real pain is seldom present unless the pericardium is affected. If the myocardium is much inflamed at the same time, the heart becomes more rapid and the blood tension lowered, and the apex beat diminished in intensity and perhaps not palpable. If there is pain, with or without pericarditis, it is often referred to the epigastrium, especially in children. The patient is often nervous, restless and sleepless. In simple endocarditis emboli rarely occur. ”

“ The heart, which has differentiated muscular walls, becomes secondarily connected at its ends with these blood spaces.
4. The pericardium and epicardium (see p. 83) originate as outgrowths from the archenteron. They may therefore be regarded as enterocoelic spaces. The pericardium becomes completely closed off and separated from the alimentary canal. The epicardium may form paired tubes of great length, and may remain permanently connected with the branchial sac.
5. The cavities of the renal vesicles and of the gonads and ducts are spaces formed in the mesoblast. ”

“ Although the pericardium and heart are situated in the median plane, percussion and auscultation should be performed on the left side, since the anterior and cardiac lobes of the left lung are less developed than those of the right; but the heart can be auscultated on the right side, as is advisable at times. ”

“ But all the unpleasant sensations in the region of the heart are not caused by an increased amount of fluid in the pericardium, as this disease is not of frequent occurrence.
335. The heart is composed of muscular fibres, that traverse it in different directions, some longitudinally, but most of them in a spiral direction. The human heart is a double organ, or it has two sides, called the right and the left. ”

“ As the result of calcification of an old pericarditic exudate the heart may be surrounded by a calcareous sheath (“stony heart,” “petrified heart”) . Hæmopericardium results from the rupture of the heart, aorta, pulmonary artery or coronary vessel. Petechiæ of the peri- and epicardium are found in pyæmia, septicæmia, hæmophilia, scurvy, severe anæmia, leukæmia, chronic nephritis, and death from suffocation and various intoxications. Pneumopericardium may be due to perforating wounds, or to perforations from lungs, stomach or œsophagus, or to infections with gas-forming bacilli. ”

“ TREATMENT OF ACUTE PERICARDITIS In acute pericarditis, absolute mental as well as physical rest is essential. Even if the patient does not appear to be seriously ill and has not much fever, he should not be allowed to have visitors, to discuss business matters, or to carry on any conversation, however little exciting. Anything which increases the heart beat increases the irritation of the inflamed surfaces of the pericardium. He should not be allowed to sit up, either to eat or to attend to the calls of Nature. ”

“ Between these adhesions, which form partitions, are found little cavities filled with sero-sanguinolent, grumous, or caseous liquid. In time the adhesions increase in number, pericarditis obliterates the free space, and the heart becomes wholly adherent to the pericardium.
As in acute pericarditis, the fibrous layer undergoes thickening and hardening processes. The superficial layers of the myocardium undergo sclerous transformation, and the tissues forming the adhesions themselves may assume the characters of fibrous tissue. ”

“ The heart is surrounded by a pericardium, from which at regular intervals a number of dorso-ventral muscles pass, to be inserted into the longitudinal venous sinus on each side. These veno-pericardial muscles are absolutely segmental with the mesosomatic segments, and are confined to that region, with the exception of two pairs in the prosomatic region. ”

“ In all cases of bloody, serous, purulent, or aërial effusions into the pericardium, that present dangerous symptoms of heart failure, operative interference should be undertaken as soon as it is evident that medication is not lessening the embarrassment of the central organ of circulation. ”

“ If it encroaches on the liver, symptoms of hepatic disorder supervene. Its progress through the lung or pleura is marked by objective symptoms of pulmonary or pleural inflammation (crepitation, flatness or percussion, creaking or friction sounds) , but without the customary amount of hyperthermia, and with some evidence of gastric disorder. When the pericardium is reached there are the usual signs of pericarditis, attended by comparatively little fever, and a doughy swelling beneath the sternum is added to the objective signs of exudation in the pericardium. ”

“ The two canals which form the communication between the pericardium and the branchial cavity commence at the receptacle of the lesser cluster attached to the superior branchial arteries, and terminate at the papillæ before mentioned, which are situated at the roots of the branchiæ. The pericardium and these receptacles of the glands, when first laid open, were found filled with a coagulated substance so closely compacted as to require a careful removal, bit by bit, before the contained follicles and vessels could be brought into view. ”

“ What proves it is, that at the death which follows the disease, the serum of the pleura, the pericardium, the peritoneum, &c. varies remarkably. Sometimes it is evidently increased, at others it is almost nothing; this depends upon the time in which the subject died. If it is whilst exhalation is very abundant, we find much serum; it is almost nothing if life has been sufficiently prolonged to allow absorption to take place. ”

“ Whether the pericardium and the ventral sinus are made to expand simultaneously or all the movement is made by one only of the surfaces concerned, must depend on conditions of tension. In any case it is clear that we have in these muscles an apparatus for causing the blood to flow differentially in increased volume into either the pericardium, through the veins leading from the respiratory organs, or from the body generally into the great sinuses which bring the blood to the respiratory organs. ”

“ Treatment. The treatment of pericarditis due to the presence of foreign bodies is at present merely palliative. Often the only thing to be done is to slaughter the animal.
We need not go back to the methods formerly recommended. All are illusory or mischievous, such as the use of purgatives to arrest or reverse the progress of the foreign body, removal of the foreign body after opening the rumen, puncture of the pericardium, etc.
In 1878 Bastin successfully opened the pericardium and extracted the foreign body through a window produced in the thoracic wall. ”

“ On opening the chest, the heart was free from disease, with rather more water in the pericardium than natural; the lungs were completely gorged with grumous blood, and the pleura adherent on the right side. On removing the cranium, which was remarkably thin, and cutting the substance of the brain, numerous red spots presented themselves in the medullary portion ”

“ We find valves for a similar purpose placed at the origin of the pulmonary artery and the aorta, which proceed from the right and left ventricles, and are the channels by which the blood flows through the former to the lungs, through the latter to the general circulation. The chambers of the heart are lined by a smooth membrane of a serous character, called the endocardium, which is often the seat of disease; and the whole is enclosed in a fibro-serous sac, called the pericardium. ”

“ The pulmonary lobe between the heart and chest wall may be thrust upwards and be partially adherent to the pericardium and to the parietal pleura, and at the same time it may be impossible to avoid 386producing operative pneumo-thorax when the cartilages are resected to admit of incising the pericardium. ”

“ The vascular system is very highly developed; the heart consists of a pair of auricles and a ventricle (figs. 12, 28) . Branchial hearts are formed on the afferent vessels of the branchiae. It is not known to what extent the minute subdivision of the arteries extends, or whether there is a true capillary system.
The pericardium is extended so as to form a very large sac, passing among the viscera dorsalwards and sometimes containing the ovary or testis—the viscero-pericardial sac—which opens to the exterior either directly or through the renal organs. ”