11KA11T. 



581 





(roliiiiniic utrnca, terries lacerti) project from 

 the inner surface. \\e will find that they 

 pliant three different appearances in both 

 ventricles. 1. The more numerous are attached 

 to the walls of the ventricles by their two 

 extremities, so that we can introduce a probe 

 under the middle part. These divide and sub- 

 divide in a variety of ways. 2. Others are 

 attached to the walls of the ventricles by the 

 whole of their external surface, while their 

 internal surface stands in relief from these walls. 

 3. Others are fixed to the walls of the ventricle 

 by their lower extremities, are perfectly free in 

 the rest of their course, and terminate either 

 in a blunt extremity or in several short pro- 

 cesses. These last are few in number, nearly 

 vertical, and have received the name of niuscuti 

 jiapilliires. These columnar carneae form an in- 

 tricate network on the inner surface of the 

 ventricle, and some of them occasionally cross 

 its cavity near the apex. They are more 

 numerous on the anterior and external than on 

 the posterior and internal walls. Two large 

 openings are placed at the base of the ventricle. 

 The larger, oval in the empty, somewhat cir- 

 cular in the distended heart, is the right 

 auriculo-ventricular opening, the upper margin 

 of which was already seen in the right auricle. 

 The smaller is circular, is placed anterior and 

 to the left, is about three-quarters of an inch 

 higher than the larger, and is the orifice of the 

 pulmonary artery. That portion of the ven- 

 tricle from which the pulmonary artery springs 

 is prolonged upwards above the level of the 

 rest of the ventricle. To this prolongation 

 Cruveilhier has given the name of the infun- 

 dibulum.* 



The inner surface, particularly the posterior 

 part of this infuudibulum, is smooth and 

 deprived of columnar carnea,'. Around the 

 auriculo-veiitrirular opening a valve is placed, 

 the fixed margin of which is attached to the 

 circumference of the opening; the free margin 

 projects into the ventricle. This valve, which 

 forms a complete ring at its attachment, termi- 

 nates in several apices, three of which are much 

 more prominent than the rest, and on this 

 account it receives the name of the tricuspid 

 or trlglochin valve (valvula triglucfiis v. tri- 

 cuspis). The anterior of these three portions, 

 which is placed on the side nearest to the orifice 

 of the pulmonary artery, is more prominent and 

 broader than the posterior and internal portions, 

 ami is separated from them by deeper notches 

 than these two are from each other. From this 

 circumstance some are inclined to consider this 

 valve as consisting of two portions only. It 

 contains several small luberclesat its free margin. 



* This part is vory minutely described by Wolff 

 under the term coints arli-riusus. Under the term 

 iiif'm,ilt l 'nlian WoltV included ;i l.irger portion o{ the 

 ventricle, apparently that portion placed above a 

 line drawn ironi the upper and right margin of the 

 ventricle obliquely downwards to the anterior li-^ure. 

 As the upper part of the right ventricle becomes 

 gradually narrower, he supposed that it increases 

 the velocity and impetus of the blood as it is driven 

 from the ventricle. Acia Aoad. Imper. I'ctropol. 

 pro anno 1780, torn. vi. p. 209. 1784. 



Tins valve, like the other valves at the arterial 

 and left auricular orifices, to be afterwards 

 described, is composed of a reduplicatureof the 

 lining membrane containing some tendinous 

 fibres between them. It is translucent and of 

 great toughness. A number of tendinous cords 

 ( flnmla- trndinea) pass between the apices of 

 these valves and the inner surface of the ven- 

 tricle. Though the arrangement of these chordae 

 tendineae is not uniform in all cases, yet it is 

 of importance to remark, as prominently bearing 

 upon the discussions connected with the man- 

 ner in which these valves at the auriculo-ven- 

 tricular opening perform their office, that their 

 general distribution is the same, and evidently 

 intended for a specific pur|x>se.* The greater 

 part of these chordae tendineae spring from the 

 free and blunt extremities of the third kind of 

 columnar carneae (muscitli pupil/ares) which 

 we have described ; some from the other two 

 kinds, and others again from the smooth portion 

 of the septum, and more particularly from the 

 lower part of the smooth surface which leads 

 into the infundibulum. These tendinous cords 

 diverge to reach their insertion, some of them 

 dividing and subdividing two or three times, 

 occasionally crossing each other, and are 

 inserted principally into the apices and margins 

 of the notches which separate the valve into its 

 three portions. A few of these cords pass 

 between the columnae and inner surface of the 

 ventricle without being attached to the valve. 

 The internal lip of the valve has its lower 

 margin tied more closely down to the surface 

 of the ventricle by these cords than the other 

 two lips ; besides several short cords frequently 

 pass between the internal surface of the ven- 

 tricle and the ventricular surface of that portion 

 of the valve. At the exit of the pulmonary 

 artery from the upper, anterior, and left part of 

 the ventricle, three valves are placed (fig. 268). 

 These from their form have received the name 

 of semilunar or sigmoid valves. Their fixed 

 margins are convex,and adhere to the tendinous 

 ring to which the origin of the artery is attached ; 

 their free edges, from the presence of a small 

 triangular tubercle in the middle of each (cor- 

 pus Arantli, corpusculiim JHorgngni, corpus 

 sexiimoideum,) form two slight semilunar curves 

 (7?g.268). Theextremitiesof the curved attached 

 edges look in the course of the artery. When 

 the blood rushes from the ventricle into the 

 pulmonary artery, the valves are laid against 

 the sides of the vessel, and the free edge becomes 

 vertical ; when, on the other hand, a portion of 

 the blood falls back towards the ventricle, the 

 valves are thrown inwards and completely 

 occupy the calibre of the artery. At this time 

 the concave surfaces of the valves are directed 

 in the course of the artery, the convex surfaces 

 towards the ventricle. These valves may be 

 distinguished by the terms anterior, posterior or 

 left, and superior or right. The suggestion of 



* Mr. T. \V~. King states (Guy's Hospital Reports, 

 no. iv. p. 123.) that there is a disposition in the 

 chorda? tendinex from each fleshy column to attach 

 themselves to the adjoining edges of two lips of the 

 valve, as iu the left ventricle. 



