AKCH OF THE AOETA. 



887 



inferior vena cava. Its lower part is in direct relation, on the right side, with the inferior 

 vena cava. On the left side, the left crus of the diaphragm with the left cceliac ganglion, 

 and the terminal portion of the duodenum, are in close relation with its upper part, whilst 

 in the lower portion of its extent the peritoneum and some coils of the small intestine 

 are in contact with it. Lumbar lymph glands lie around it, on all sides. 



Branches. The branches form two groups, visceral and parietal, and each group 

 consists of paired and unpaired vessels, as follows : 



Visceral. 



Unpaired. 



Paired. 



Cceliac 



Superior mesen- 



teric 

 Inferior mesen- 



teric 



Suprarenal 

 Renal 



Testicular or 

 ovarian 



Parietal. 



Unpaired. 



Middle sacral (which 

 is the original 

 continuation) 



Paired. 



Inferior phrenic 



Lumbar (four pairs) 

 Common iliac 



BRANCHES OF THE ASCENDING AOKTA. 



ARTERLE; CORONARI^E. 



The coronary arteries are two in number, a right and a left ; they are distributed 

 almost entirely to the heart, but give also some small branches to the roots of the 

 great vessels, and to the pericardium (Figs. 750, 751, and 754). 



The right coronary artery springs from the anterior aortic sinus. It runs 

 forwards, between the root of the pulmonary artery and the auricle of the right 

 atrium, to the coronary sulcus, in which it passes downwards and to the right to 

 the junction of the right and inferior margins of the heart. There it turns to the 

 left, in the inferior part of the coronary sulcus, as far as the posterior end of the 

 inferior interventricular sulcus, where it gives off its interventricular branch 

 and then ends by anastomosing with the circumflex branch of the left coronary 

 artery. It is accompanied by branches from the cardiac plexus and the right 

 coronary vein. 



Branches. The interventricular branch runs forwards in the inferior interventricular 

 .sulcus ; it supplies both ventricles, and anastomoses, at the apex of the heart, with the inter- 

 ventricular branch of the left coronary artery. 



Aortic and pulmonary twigs are distributed to the roots of the aorta and pulmonary artery 

 respectively. A right atrial branch passes upwards on the anterior surface of the right atrium, 

 tween it and the ascending aorta ; one or more anterior ventricular branches, of small size, 

 descend on -the anterior surface of the right ventricle ; a branch of larger size, the right 

 marginal artery, runs along the inferior margin of the heart and gives branches to both 

 surfaces of the right ventricle. 



The left coronary artery arises from the left posterior aortic sinus. Its short 

 trunk runs forwards, between the root of the pulmonary artery and the auricle of the 

 left atrium, to the coronary sulcus at the upper end of the anterior interventricular 

 groove, where it divides into a circumflex and an interventricular branch. 



Branches. The circumflex branch runs to the left margin of the heart, and there turns to 



the inferior surface where it comes into relation with the coronary sinus ; it ends by anastomos- 



ith the right coronary artery. It supplies branches to the left atrium, the left margin of 



heart, and the posterior part of the inferior surface of the left ventricle. The inter - 



icular terminal branch passes down the anterior interventricular sulcus to the apex of 



i heart, where it anastomoses with the interventricular branch from the right coronary ; it 



s both ventricles, and is accompanied by cardiac nerves and by the great cardiac vein. 

 A left atrial branch or branches of small size pass to the wall of the left atrium, and small 

 rtic and pulmonary branches are also given to the roots of the aorta and pulmonary artery. 



BRANCHES OF THE ARCH OF THE AORTA. 



The branches which arise from the arch of the aorta supply the head and neck, 

 i upper extremities, and part of the body wall. 



57c 



