936 



THE OR(;AyS OF rTRC'T'LATlOX 



tricular wall in the adult is nmch thinner than the left, being thickest at the base, 

 and thinnest at the apex. 



The left ventricular wall is about double the thickness of the right; and it is 

 thickest where the ventricle is broadest, being thinner both at its base and apex. 



The Vessels and Nerves 



The arteries. — The two coronary arteries, right and left, arise, the right from 

 the anterior, and the left from the left posterior sinus of Valsalva just above the 

 free borders of the right, and of the left posterior semilunar valves. 



The right coronary artery ])asses fonvards between the pulmonary artery and 

 tlu^ right auricular ajtjxndix. and then winds to the right border of the heart, around 

 whiili it turns to gain its po.sterior surface. In this course it lies in the aurifulo- 



FiG. 5r)5. — Anteeior View of the Heart, showing its Arteries and Veins. 



Innomiiiati' 



Right jiulinoriari/ vein 



RIGHT AURICLE 

 RIGHT AURICLE APPENDIX 



liiffht loronary 



Btanrh lo anterior wall 

 of right ventricle (pre- 

 venlricn/or) 



Riff/it inarginnl artery 

 and vein {rein of Galen) 



Lfft carotid 

 Lej'l snbclarian 



Lfft jjiilnioiiiiri/ vein 



LEFT AURICULAR .WENDIX 



Left DKirginal artery 



A nlerior interrenlricnlar 

 lirunch of the great cnr- 

 •tiac vein 



[.■ft coronary (interven- 

 tricular) 



'iininteucing radicles of 

 posterior interventric- 

 ular vein 



ventricular groove. At the commencement of the posterior interventricular groove 

 it divides into its two main branches, one of which, still i>assing onwards in the 

 auiiculo-ventricular groove, anastomoses with the left coronary, whilst the other 

 ( interventricularj descends in the furrow between the ventricles towards the 

 apex, near whicli it anastomoses with branches derived from the left coronary 

 artery which have reached the posterior surfa(;e of the heart after passing around 

 its apex. In this course the right coronary artery sup])lies branches to the riglit 

 auricle ( auricular j and roots of the pulmonary artery and aorta, as well as one 

 that descends near the right border of the heart (right marginal), and a second 

 (preventricular) to the anterior Avail of the right ventrick-. It supplies both 

 ventricles and the septum. 



The left coronary artery passes for a short distance forwards, between the 

 pulmonary artery and tliu left auricular a{)pendix, and then divides into two prin- 

 cipal branches, one of whicli descends in the interventricular groove to the apex of 



