Circulation of Blood through the Heart – Location of the Heart – Space over which Normal Dullness is found – Sounds of the Normal Heart – Sounds of the Abdominal Heart.
GENTLEMEN : Before I proceed to describe the Diseases of the Heart, it is proper that we inquire into the method of the circulation of the blood in and through that organ.
The venous blood which is returned by the ascending and descending vena cava, enters the right auricle during its diastole.
Part of it flows on into the right ventricle during the earlier part of its diastole; but the auricle being filled before the ventricle, then contracts, and discharges its contents through the tricuspid valves into the ventricle, which is thus completely distends.
The reflux of blood into the veins during the auricular systole, is impeded by the contraction of their own walls, and by the valves with which they are furnished; but these valves are so formed as not to close accurately, especially when the tubes are distended; so that a small amount of reflux usually takes place, and this is much increased when there is any obstruction to the pulmonary circulation.
Whilst the right ventricle is contracting upon the blood that has entered it, the carneae columnae, which contract simultaneously with its proper walls, put the chordae tendinae upon the stretch, and these draw the flaps of the tricuspid valve into the auriculo-ventricular axis.
The blood then getting behind them, and then being compressed by 2 the contraction of the ventricle, forces the flaps together in such a manner as to close the orifice; but they do not fall suddenly against each other, as is the case with the semi-lunar valves, since they are restrained by the chordae tendinae, whence it is that no sound is produced by their closure.
The blood after having circulated through the lungs, returns as arterial blood by the pulmonary veins to the left auricle; whence it passes through the mitral valve into the left ventricle, and thence into the aorta through its semi-lunar valves, in the same manner as that on the other side.
We will now proceed to describe and determine the
LOCATION OF THE HEART,
and the space in which normal dulness is found.
The heart is situated between the cartilages of the third and sixth ribs. The upper extremity, or base, is defined with sufficient precision by the upper margin of the third rib. The point or apex generally extends to the fifth intercostal space, near the junction of the rib to its cartilage. The organ is situated obliquely within the chest, a line passing through the longitudinal axis, intersects obliquely the clavicle near its acromial extremity. The medial line and the linea mammalis, are convenient landmarks for indicating the space which the heart occupies transversely. The median line divides the heart, leaving about one-third on the right, and two-thirds on the left side. The left margin of the heart, in the male, extends to a point just within the nipple, which is situated on the fourth rib, near the junction of its rib with the cartilage. The apex is about three inches to the left of the median line, and about an inch within the linea mammalis. The right margin extends from half an inch to an inch beyond the sternum, on the right side. Viewing the several portions of the heart in relation to the median line, on the right are situated the right auricle, and about a third of the right ventricle; on the left of this line are situated two-thirds of the right ventricle and the left auricle.
The relations of the heart to the adjacent organs are important with reference to the sign furnished by percussion, also by the other methods of exploration. At the base are the large arteries connected with the ventricles, viz., the aorta and pulmonary artery, which extend up beneath the sternum – the latter to the level of the upper margin of the second, and the former nearly as high as the first rib. The portion of the heart situated on the right of the median line is covered by the right lung. The lower border of the heart, to the left of the median line, lies on the diaphragm which separates it from the left lobe of the liver, and, towards the apex, from the stomach. The portion of the heart lying to the left of the median line, is only partially covered by the left lung – a part is in contact (the pericardium only intervening) with the thoracic walls.
The space on the chest within which the heart is not covered by lung, is called the superficial cardiac region.
The praecordial space within which the heart is covered by lung is called the deep cardiac region.
These names should be remembered, for they will frequently occur.
The boundaries of the superficial cardiac region are thus given: It is bounded on its sides by lung, and on the greater part of one side, viz., the lower, by the liver and stomach, with the diaphragm intervening. The portion of the heart’s surface exposed, is an irregular quadrangle. This space may be embraced within a right angled triangle delineated as follows: The oblique line, or hypothenuse, is drawn by connecting a point at the centre of the sternum on a level with the junction of the fourth costal cartilage, with the point where the apex of the heart comes in contact with the thoracic walls, the latter being usually in the fifth intercostal space, about an inch within the linea mammalis, or about three inches to the left of the median line. the median line extending from the same point on the sternum, and a line extending transversely from the point of the apex-beat to meet the median line, will form the two other sides of the triangle.
The limits to which the deep cardiac region extends have been already defined in giving the boundaries of the space which the heart occupies within the chest.
The dullness over the superficial cardiac region is more decided than over the deep-seated cardiac region, owing to the fact that it is not covered by lung. This dulness can be recognized by light percussion. It requires forcible percussion to mark out the dulness over the deep cardiac region.
[For full and minute directions to examine by percussion, consult Walshe or Flint on Diseases of the Heart.]
If the dulness, found on examination of a patient, exceeds the limits given above, we may conclude that some kind of enlargement exists. The heart, in proportion to its increase in volume, pushes aside the anterior border of the left lung, leaving a large portion of its anterior surface uncovered and in contact with the thoracic walls. The degree of dulness within the superficial cardiac region is greater than in health in proportion to the enlargement. Increased extent and degree of superficial dulness are signs of enlargement of the heart, provided the adjacent organs are healthy. The presence of phthisis, chronic pleurisy, enlargement of the liver, dilatation of the stomach, aneurism of the aorta, enlarged spleen, ascites, pregnancy, may cause difficulty in making a correct diagnosis by means of percussion.
The limits of this work will not permit us to go further into this subject. For full and exact knowledge relating to the physical diagnosis of abnormal conditions discernible by percussion, reference must be had to the works previously alluded to.
THE SOUNDS OF THE NORMAL HEART.
When the ear is applied over the cardiac region, during the natural movements of the heart, two successive sounds are heard, each pair of which corresponds with one pulsation; there is also an interval of silence between each recurrence, and the sound that immediately follows this interval is known as the first sound, the other as the second.
The first sound of the heart is caused by the contraction or systole of the ventricles, and is called the systolic sound. The second sound is caused by the dilation or diastole of the ventricles, and is called the diastolic sound.
The first sound is heard plain, over the apex of the heart, or where the apex-beat is felt.
The second sound is best heard just above the base of the heart, in the intercostal space between the second and third ribs, close to the sternum.
The first sound, over the apex, is longer, lower, and has a “blowing” quality.
The second sound, in the second intercostal space on either side, is shorter, more acute, and has a clicking or valvular quality.
In order to get a clear idea of the heart-sounds,, the stethoscope should be used. The bin-aural stethoscope is considered superior to all others for this purpose.
If the ear is applied to the praecordia, the sounds from different sources are commingled, and they cannot be so well studied separately.
The second sound of the heart varies, as we study it on different sides of the sternum, in the space between the second and third ribs.
On the right side the sound is more acute, more abrupt, louder, and apparently nearer the ear, and is said to be caused by the movements of the semi-lunar valves of the aorta.
On the left side the sound is less acute and emanates from the valves of the pulmonary artery, and due to their expansion succeeding the ventricular systole.
Hale wrote Lectures On Diseases Of The Heart, Materia medica and special therapeutics of the new remedies Volume 1, Materia Medica And Special Therapeutics Of The New Remedies Volume 2, Saw Palmetto: (Sabal Serrulata. Serenoa Serrulata), The Medical, Surgical, and Hygienic Treatment of Diseases of Women, New Remedies: Their Pathogenetic Effects and Therapeutic Application, Ilex Cassine : the aboriginal North American tea, Repertory to the New Remedies with Charles Porter Hart, The Characteristics of the New Remedies, Materia Medica and Special Therapeutics of the New Remedies, The Practice of Medicine, Homoeopathic Materia Medica of the New Remedies: Their Botanical Description etc.