THE POSTEEIOn AORTA. 527 



luediastinum, one above, the other below the oesophagus, which they accompany 

 for a short distance, from before to behind, to the extremity of that canal. 



The superior oesophageal artery, much more voluminous than the inferior 

 inosculates with a branch of the gastric artery. In its course it gives descend- 

 ing branches to the oesophagus, and ascending ones to the mediastinum. 



The inferior oesophageal artery also anastomoses with a branch of the 

 gastric ; most frequently with that noticed above. It likewise furnishes 

 ascending and descending divisions; the latter, however, going to the 

 mediastinum, and the former to the oesophagus. 



• Innominate Eamuscules. — The innominate ramuscules of the broncho- 

 oesophageal trunk do not all come directly from it ; there being always 

 a certain number which emerge from the bronchial or oesophageal arteries. 

 They are more particularly distributed to the trachea, to that portion 

 of the oesophagus which is in contact with the posterior extremity of this 

 cartilaginous tube, to the bronchial glands, the mediastinum, and the 

 pulmonary pleura. Those destined for the latter form on the surface of 

 the lung, along with the divisions of the pleural branch furnished by the 

 gastric artery, a beautiful plexus. 



2. Goeliac Artery or Trunk (or Axis). 



This artery arises at a right angle from the inferior face of the aorta, 

 immediately on the entrance of that vessel into the abdominal cavity. 

 After a course of from half to three-fourths of an inch at most, in the 

 middle of the solar plexus, and beneath the superior face of the pancreas, this 

 trunk separates into three branches : a middle, the gastric artery ; a right, 

 the hepatic artery ; and a left, the splenic artery. 



1. Gasteio Artery (the cm-onaria ventriculi of Man.) — This artery 

 descends on the large tuberosity of the stomach, extends to near the 

 insertion of the oesophagus, and then divides into two branches : the anterior 

 and posterior gastric. The first passes behind and to the right of the 

 oesophagus, and crossing the small curvature of tlie stomach, gains the 

 anterior face of that viscus, where it separates into flexuous and divergent 

 branches which run beneath the serous membrane, and are carried more 

 particularly towards the left cul-de-sac and around the cardia. The second 

 vessel is distributed in the same manner to the posterior wall of the organ, 

 but chiefly to the right sac. 



Independently of these two arteries, the gastric trunk gives off a third 

 and constant branch, which often comes from one of the two branches 

 of this trunk, and sometimes also from the coeliac artery itself, or from the 

 splenic. This branch accompanies the oesophagus, along with the right 

 pneumogastric, crosses the opening of the right pillar of the diaphragm to 

 enter the pectoral cavity, and then divides into two branches, each of which 

 anastomoses with one of the oesophageal arteries, and is then thrown over 

 the posterior extremity of pulmonary lobe, which it covers with a magnifi- 

 cent subpleural reticular arborisation. This gastro-pulmonary artery often 

 anastomoses with the superior oesophageal branch only, and goes exclusively 

 to the right lung ; for the left lung and the inferior oesophageal artery, 

 in this case there is a special branch which emanates from the anterior 

 gastric. It is not rare to meet with varieties of another kind, but of which 

 it is not necessary to speak ; inasmuch as in these pleural ramifications we 

 find a disposition common to the whole arterial system : distribution almost 

 invariable, origin very inconstant. 



2. Splbnio Artery. — The largest of the three branches of the coeliao 



