THE AORTIC ARCH. 



333 



itself, and crosses obliquely behind the sternum, approaching at the same 

 time more nearly to that bone. Having gained the level of the upper 



Fig. 249. VIEWOFTHE 

 AORTA FROM BEFORE, 

 WITH THE FIRST PART 

 OF ITS PRINCIPAL 

 BRANCHES DISSECTED 

 OUT OF THE BODY 

 (from R. Quain). \ 



1, commencement of 

 the aorta at the place 

 where it has been sepa- 

 rated from the left ven- 

 tricle, showing below the 

 semilunar valves closed, 

 in front and at the sides 

 the dilatations corre- 

 sponding to these valves, 

 or sinuses of Valsalva, 

 and above these the 

 origin of the right and 

 left coronary arteries ; 

 2, the ascending part of 

 the arch, with the dilata- 

 tion termed sinus of the 

 arch ; 3, the back of the 

 arch, or termination of 

 its descending portion ; 



4, innominate artery ; 



5, left carotid ; 6, left 

 subclavian ; 7, hollow 

 of the arch ; and, far- 

 ther down the aorta, 

 7, 7, indicate two out 

 of the series of inter- 

 costal arteries : the ceso- 

 phageal arteries are also 

 seen rising from the 

 front of the thoracic 

 aorta; 8, 8, right and 

 left renal arteries ; 9, 

 9, right and left com- 

 mon iliac arteries ; 10, 

 middle sacral artery ; 

 H, marks one of the 

 inferior diaphragmatic 

 arteries ; + , the coeliac 

 axis ; 12, the gastric 

 artery ; 13, the hepatic; 

 14, the splenic; 15, 

 superior mesenteric ; 



16, inferior mesenteric ; 



17, 17, right and left 

 spermatic arteries. 



Fig. 250. VIEW OF THE 

 AORTA FROM BEHIND, 

 WITH ITS PRINCIPAL 



BRANCHES (from R. 



Quain). 



The numbers have the same signification as in Fig. 249. The origin of the right and 

 left intercostal arteries close to each other and near the middle of the aorta posteriorly is 

 shown. 



