8 



diameter, lined by a smooth cellular membrane, invested with a layer of 

 epithelium, and presenting no distinct opening into it. The right inno- 

 minate artery is about two inches and a half in length, forming a curve 

 concave to the right ; it gives off the carotid and subclavian branches, 

 the latter being small and passing outwards, the former ascending. 



In connexion with the carotid artery is a large, brownish, glandular 

 mass, about an inch in diameter, supplied by many arteries, and emitting a 

 large number of veins : this and its fellow of the left side are the lateral 

 lobes of the thyroid body without an isthmus. The left innominate is 

 similar to the right in most respects. Prom the commencement of the 

 subclavian a small cervical branch — the vertebral — passes upwards into 

 the posterior portion of the neck. The pulmonary artery arises from 

 the infundibulum of the right ventricle, is about two and a half inches 

 long,- and one inch and a half in diameter ; it passes upwards, 

 backwards, and to the left, and then divides into right and left 

 branches. The trunk lies in front of the aorta, and its bifurca- 

 tion corresponds to the front of the termination of the trachea. The right 

 branch passes through the grasp of the arch of the aorta, is rather smaller 

 than the left, runs downwards, backwards, and to the right side, lying 

 above the right bronchus. The cardiac nerves of the right side run pa- 

 rallel to its upper border as far as the anterior part of the root of the aorta, 

 where they end in forming the coronary plexuses to supply the muscu- 

 lar substance of the heart. The left pulmonary artery is larger, more an- 

 terior, and superior, than the right, but nothing of importance is discerni- 

 ble in its course. The great veins are three in number — two superior 

 cavse, and one inferior: the left superior cava is formed by the union of the 

 jugular and subclavian veins with several smaller vessels from the thoracic 

 parietes. This vessel lies posterior and external to the sterno-tracheal 

 muscle, and internal to the furculum. The length of this vein before it is 

 joined by the azygos is three inches, and this latter vessel unites with it 

 just as it is passing into the pericardium, and an inch and a half from 

 its entrance into the auricle. This vein runs downwards, backwards, 

 and to the right side. The left vena azygos begins in the abdomen, 

 at the upper border of the ovaries, passes over the diaphragm, and runs 

 obliquely on the side of the pericardium, behind the left lobe of the liver, 

 and terminates in the left superior cava. The right superior cava is 

 double the size of the left, with which it corresponds in many points, 

 its orifice being separated in the auricle from the inferior cava by a 

 membranous valve, the great Eustachian, which guards the mouth of 

 the latter : as this vessel is passing downwards, and to the left side, it 

 receives the right vena azygos, a very small vessel, scarcely admitting 

 an ordinary probe, which passes between the pleura and pericardium on 

 the right side, and passes behind, and to the right of the auricle. The 

 pulmonary veins are two in number, one on either side ; the left is the 

 longest, and is placed below the bronchus, and was in the female 

 plugged up by a firm fibrinous coagulum. These vessels coalesce as they 

 approach the auricle. 



"When these various organs are removed, a complex system of 

 septa is exposed; of these there are five portions — one transverse, a 



