Mitral Disease 173 



unusual strain. Haemorrhage even in such circumstances should be 

 regarded with anxiety, though it may be merely of physiological 

 import. It is probable that the safety arrangement not only insures 

 the right side of the heart against strain, but also against disease. 

 A similar arrangement, desirable though it might seem, could not 

 exist at the left auriculo-ventricular opening, as the lungs would in- 

 evitably suffer by it. 



Murmurs from disease of the pulmonary value are best heard over 

 the third left cartilage, that is over the valve ; they grow fainter 

 towards the apex. They are distinguished from aortic murmurs by 

 their occupying a limited area ; they certainly do not ascend into the 

 neck (p. 171). They are usually the result of congenital malformation. 



When the left aurictilo-ventricular valve (mitral) is narrowed an 

 obstruction-murmur may be heard immediately preceding the ventri- 

 cular contraction. It is the presystolic murmur, and is of compara- 

 tively rare occurrence. When listening for it a finger should be kept 

 on the radial pulse, so that the observer may know exactly when to 

 expect it. The murmur runs with the blood-stream, and is heard over 

 the apex. 



Mitral re gurgitation, a very common defect, occurs when the left 

 ventricle is pumping blood backwards through the incompetent auri- 

 culo-ventricular valve the murmur, of course, takes place with systole. 

 It does not ascend into the large vessels at the root of the neck, as 

 does a systolic aortic murmur, but is loudest heard in those regions 

 where the ear can be approached to the left ventricle without the inter- 

 vention of the right ventricle, as in the neighbourhood of the apex ; also 

 below the left shoulder-blade, and behind the lower middle dorsal 

 vertebrae, the seventh and eighth (p. 166), for there the left ventricle is at 

 the back of the heart, and in that direction the blood is rushing. As 

 the left ventricle lies close over the stomach, a mitral murmur may often 

 be heard in the gastric region, with that peculiar metallic thrill which is 

 due to the vibrations passing across the stomach full of gas (v. p. 164). 



The murmur of aortic obstruction is not best heard over the mid- 

 sternum, that is over the situation of the aortic orifice (p. 169), for at 

 this level the valve is deeply hidden behind the right ventricle and the 

 root of the pulmonary artery ; but the sound, being carried by the 

 blood-stream, is heard where the aorta comes near the surface, as 

 at the second right costal cartilage, behind the manubrium, in the 

 large vessels at the root of the neck, and along the dorsal spine. It 

 occurs with ventricular contraction, and is, therefore, synchronous 

 with the radial pulse. * 



The murmur of aortic regurgitation is not well heard in the neck, 

 for the regurgitant blood is actually rushing away from that region, 

 back into the left ventricle. The carotids, however, which are half- 

 emptied before the ventricle contracts again, fill and throb visibly 

 with systole, especially when the patient sits or stands, as gravity in- 



