DIMENSIONS OF THE HEART. 217 



of the heart below, rests upon the bottom of the pericardium, 

 covering the cordiform tendon of the diaphragm. The apex of 

 the heart, formed by the extremity of the left ventricle, is nearly 

 opposite the junction of the fifth rib with its cartilage at true dis- 

 tance of two or three inches from the sternum. 



Dimensions of the Heart. 



The heart was said by Laennec, to be of the size of the closed 

 fist of the same subject. But this is a rule upon which little 

 reliance can be placed. It was found by very accurate ob- 

 servations made by M. Bizot,* on one hundred and fifty- 

 six subjects of ages varying from one to eighty that the 

 heart has no natural limit in regard to size, but increases 

 indefinitely without being diseased, according to the age of the 

 subject. After fifty years, however, the growth is so slow, as 

 to be scarcely noticeable, except it become diseased. 

 In 18 subjects between the ages of 16 and 29, on the average 

 the length was 42 lines; breadth 46; thickness, 17J. In J9, 

 between the ages of 50 and 79, the average length was 46 lines ; 

 breadth 53 ; thickness 18;. In females upon the average at the 

 same ages, the dimensions were each about three lines less. 

 The dimensions of the heart are directly in relation to the 

 breadth of the shoulders, and by careful observations made upon 

 sixty-four subjects, consisting of nearly an equal number of each 

 sex, it was found by M. Bizot, that in individuals of middle 

 stature and under, that the heart was absolutely of greater 

 size, than in those who were distinguished for their tallness. 

 It has been asserted by Andral,f that the four cavities of the 

 heart, in their natural and healthy state, are as near as may be 

 of equal dimensions ; and by M. Beclard,^ that the right ven- 

 tricle as age advances, becomes enlarged in a greater proportion 

 than the left. 



* Mem. de la Societe Med. d'Observation de Paris, 1836. 



f Diet, de Med. nouv. ed. torn. viii. 



| Lieutaud and Sabatier, thought the cavities of the ventricles were equal in 

 the healthy state, and that the cavity of the right was enlarged by the respira- 

 tory struggles at the time of death. It has been proved, however, long since, 

 by Legallois, that the mode of death has no effect in altering the form of the 

 heart. P. 



VOL. II. 19 



