COMMON BRACHIOCEPHALIC TRUNK OR ANTERIOR AORTA 



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BRANCHES OF THE THORACIC AORTA 

 I. CORONARY ARTERIES 



The two coronary arteries, right and left, are chstributed ahiiost entirely to 

 the heart, but send some small twigs to the origins of the great vessels. 



The right coronary artery (A. coronaria dextra) arises from the anterior sinus 

 of the aorta. It passes forward between the conus arteriosus and the right auricle 

 (appendix) to the coronary groove, in which it curves around to the right and back- 

 ward. It then descends in the right ventricular groove almost to the apex of the 

 heart. 



The left coronary artery (A. coronaria sinistra) arises from the left posterior 



Pulmonary veins 



Right coronary 

 artery 



Descending branch of 

 left coronary artery 



Great coronary vein 



jjf Great coronary 



vein 

 Left coronary 

 artery, circumflex 

 branch. 



Fig. 427. — Cardiac Vessels of Horse, Left Side. 

 The dotted lines indicate part of the left coronary artery which is concealed by the left auricle. 



sinus of the aorta, passes to the left behind the origin of the pulmonarj- artery, 

 and divides into two branches. The descending branch (Ramus descendens) 

 passes down the left ventricular groove toward the apex. The circumflex branch 

 (Ramus circumflexus) runs backward in the coronary groove, in which it winds 

 around to the right side. 



2. COMMON BRACHIOCEPHALIC TRUNK OR ANTERIOR AORTA 



The common brachiocephalic trunk or anterior aorta (Truncus brachiocephali- 

 cus communis) is a very large vessel which arises from the convexity of the arch 

 of the aorta within the pericardium. It is directed forward and upward. Its 

 length in horses of medium size is usually about two inches (ca. 5 to 6 cm.), but 

 it is sometimes only half an inch or less (ca. 1 cm.). It is crossed on the left by the 

 left vagus and cardiac nerves, and the left recurrent nerve runs between it and 



