224 PRACTICAL ANATOMY. 



Name and give the importance of the openings of the right ventricle. 



The auriculo-ventricular opening, guarded by valves of like name ; the 

 pulmonary opening, at the beginning of the pulmonary artery, guarded by the 

 pulmonary semilunar valves, three in number. 



What are the sinuses of Valsalva and u'/iere do yon find them in practical 

 anatomy / 



They are pouches or dilatations behind the semilunar valves of both the 

 aorta and pulmonary artery. 



What are the c alumna carnece / 



They are muscular columns found in the ventricles of the heart. They are 

 mechanical devices for -strengthening the cardiac walls. They also give a 

 yielding attachment to the auriculo-ventricular valves. 



What are the chordce tcndime / 



Strong, glistening, tendinous threads attached by one extremity to the 

 auriculo-ventricular valves, by the other to the walls of the ventricle by the 

 medium of the columneae carneae. They inhibit the movement of the valve 

 during systole and aid recoil of the valve in diastole of the ventricles. 



Describe the blood-supply of the heart. 



The heart is supplied with blood by two arteries, called the left and right 

 coronary arteries. These arteries arise from the sinuses of Valsalva of the aorta. 

 The left arises from the posterior sinus, the right from the anterior sinus. The 

 auriculo-ventricular grooves and the interventricular grooves are where you 

 will find the main trunks of the arteries that supply the heart. 



Two anastomotic circles, a horizontal and a vertical, corresponding to the 

 grooves separating the auricles from the ventricles, and the ventricles from each 

 other respectively, may be traced out. The right coronary artery divides into 

 two main branches : the horizontal occupies the right auriculo-ventricular groove ; 

 the vertical, the right interventricular groove. The left coronary artery divides 

 likewise into two branches: the horizontal one occupies the left auriculo-ventricular 

 groove, and the vertical the left interventricular groove. In these grooves the 

 opposite arteries anastomose. 



HOT.V is blood returned from the heart / 



Veins called coronary accompany the arteries just described, and open into 

 the right auricle by the coronary sinus, which is guarded by the coronary valve. 

 This opening is between the inferior vena cava and the auriculo-ventricular 

 opening. 



