MEASUKEMENT OF THE HEART. 219 



— Circumference of the coronary arteries at their origin. 

 General mean of the left in man, 5i lines. 



" " right " 4i " 



— The thickness of the ventricles, which are at birth nearly the 

 same, go on increasing, as life advances, though not in equal 

 proportions. The walls of the right ventricle are arrested in the 

 healthy state at their maximum of thickness, much sooner than 

 those of the left. 



— The volume of the heart, and the greater or less capacity of 

 the right ventricle, have, in the healthy state, but little influence 

 over the thickness of its walls. The thickness, however, is 

 found slightly increased in advanced age. That of the left 

 ventricle increases without cessation. Hence, the assertion of 

 Andral and others, that the natural thickness of the walls of 

 the left ventricle is three or four times as great as that of the 

 right, is applicable only in advanced life. 



— Professor Cruveilhier has asserted, that the thickness of the 

 ventricles beyond which only hypertrophy is to be considered 

 as existing, are seven to eight lines for the left, and four to five 

 lines for the right. The numerous and careful measurements 

 of M. Bisot, have, however, proved this standard to be exces- 

 sive, and that a thickness of seven lines of the left ventricles in 

 man, and six in women, would be a commencement of hyper- 

 trophy, even in the last stages of life ; and that the maximum of 

 thickness in the right ventricle, from 50 to 79 years, in man is 

 but 2,^th lines, and but l\ line in woman. 



— Mean dimensions of the aorta, taken from a large number of 

 subjects at seven different points. 

 — One line on the cardiac side of the arteria innominata. 



Men. Women. 



General mean of circum- 

 ference, from 16 to 79, 33 lines. Do. from 16 to 89, 31 lines. 



Near the left subclavian, 



general mean, 33 " " 24 " 



Opposite the remains of 



the ductus arteriosus, 25 " " 23 " 



Above the cceliac artery, 22i " " 20^ " 



