. Diseases of the heart and thoracic aorta. are probably twomurmurs. Thirdly. The direction of propagation must be observed. 182 Diseases of the Heait. \i the murmur is well propag-ated, both upwards over theaorta, and outwards and upwards towards the axilla, thereare in all probability two murmurs. THE DIRECTION IN WHICH THE MURMUR IS PROPAGATED. Murmurs are propagated chiefly in two ways, viz.:—(i) Byconduction, through the structures in which they are ge-nerated, and by the parts which surround those structures.(2) By convection, carried by fluid in the direction in whichit is flo
. Diseases of the heart and thoracic aorta. are probably twomurmurs. Thirdly. The direction of propagation must be observed. 182 Diseases of the Heait. \i the murmur is well propag-ated, both upwards over theaorta, and outwards and upwards towards the axilla, thereare in all probability two murmurs. THE DIRECTION IN WHICH THE MURMUR IS PROPAGATED. Murmurs are propagated chiefly in two ways, viz.:—(i) Byconduction, through the structures in which they are ge-nerated, and by the parts which surround those structures.(2) By convection, carried by fluid in the direction in whichit is flowing. As a matter of practical experience and obser-vation, we know that the different murmurs which representdifferent valvular lesions, are propagated in certain definitedirection^, which are as follows :— Mitral regurgitant {systolic^ murmurs:—These murmursare propagated upwards and outwards towards the left axilla(see fig. 49); and, when organic, are often well heard at theinferior angle of the left scapula. According to Naunyn,. PiG. 49.—Outline figure showing point of differential maximum intensity (*)of the systolic mitral murmur (mitral regurgitation); and the direction in whichit is propagated. The cross + , which is supposed to represent the normal positionof the apex-beat, is placed a little too high. Direction of propagation of Murniiws. i8 o Balfour, and others,^ the systolic murmur, due to mitral regur-gitation, is sometimes heard in the region of the pulmonaryartery, being conducted to that part of the chest through adilated left auricular appendix. Mitral direct {presystolic^ murmur. — This murmur isusually heard over a very limited area. The blood current,v/hich produces it, is flowing directly towards the apex (orvery nearly so) of the heart. (See fig. 50-) We can readilyunderstand therefore why the presystolic murmur is usuallylimited to the position of the apex beat.
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectheart, bookyear1884
