Diseases of the chest and the principles of physical diagnosis . ure while not quite s^mchro-nous, are separatee! normally by too short a time interval to be auditorilyappreciable as separate sounds. When pathologicalh the normal pres-sure differences are exaggerated, a split, second sound is noted, a conditionwhich is more readily appreciable if the first element is the weaker of thetwo. Inasmuch as our auditory impressions of the two elements of thesecond sound are always to some extent fused, it is probable that we canrecognize one as increased over the other only when at least a 2 to 1diff
Diseases of the chest and the principles of physical diagnosis . ure while not quite s^mchro-nous, are separatee! normally by too short a time interval to be auditorilyappreciable as separate sounds. When pathologicalh the normal pres-sure differences are exaggerated, a split, second sound is noted, a conditionwhich is more readily appreciable if the first element is the weaker of thetwo. Inasmuch as our auditory impressions of the two elements of thesecond sound are always to some extent fused, it is probable that we canrecognize one as increased over the other only when at least a 2 to 1difference in intensity prevails. When a marked increase both ofpitch and intensity of the pulmonic second sound is noted, the actual 220 THE EXAMIXATIOX OF CIRCULATORY SYSTEM relative iiiten^^ity is several times greater. In attempting to estimaterelative differences in intensity- auscultation should be practised closeto the sternal margin and not at a distance from it, since the relativedifference tends to become less marked in the process of conduction(Geigel).. Fig. ISO.—Section of the viewed from ix froxt. Systolic (obstructive)aortic murmurs are transmitted in the direction of blood flow, upward into the carotidarteries. Systolic (regurgitant) mitral murmurs are transmitted in the opposite directionto the blood current, toward the left axilla, being conducted thence by the chordae tendineaeand the papillary muscles. A = aorta; P = pulmonary artery; C = carotid arteries; papillary muscle; R = right auricle; 5 = superior vena cava. THE INDIVIDUAL VARIATION OF HEART SOUNDS There is no absolutely normal standard of the heart sounds and acertain allowance must be made for individual peculiarities. As a gen-eral rule such variations can be explained either upon anatomic grounds —the size of the lungs, the depth of the chest, etc., or upon the basis of ageand sex. AUSCULTATION 221 Substernal Sounds.—In a considerable number of perfectly healthyindividuals the hea
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectdiagnos, bookyear1920
