the 



THE ABDOMINAL CAVITY. 1155 



muscular coat by the submucosa, it is thrown into a series of longitudinal folds when 

 the oesophagus is empty and contracted ; hence the stellate lumen often seen in sections 

 of the gullet. 



Glands. Numerous racemose mucous glands, the glandulas cesophageae, large enough 

 to be seen distinctly with the naked eye, are found in the submucosa. They are pretty 

 evenly distributed over the whole tube, and do not appear to be more numerous towards 

 either end. In addition to these, other glands, resembling closely those of the cardiac end 

 of the stomach, are found in the mucous membrane of certain portions of the oesophagus. 

 They are entirely confined to the mucosa, and do not extend beyond the lamina muscularis 

 mucosee. These glands are specially numerous at both the upper and lower ends of 

 the tube. 



Vessels and Nerves. Its arteries consist of numerous small branches derived, in the neck, 

 from the inferior thyreoid, in the thorax, from the bronchial arteries and thoracic aorta, and in 

 the abdomen, from the left gastric artery, and also from the left inferior phrenic. 



The veins form a plexus on the exterior of the oesophagus, from which branches pass, in 

 the lower part of the tube, to the coronary vein of the stomach, and, higher up, to the azygos, 

 and thyreoid veins. There is thus established on the lower part of the oesophagus a free com- 

 munication between the portal and systemic veins. 



The lymph vessels pass to the inferior set of deep cervical glands in the neck, and to the pos- 

 terior mediastinal glands, many of which, of large size, are seen around the tube, in the thorax. 



The nerves are derived from the recurrent, and from the cervical sympathetic in the neck, 

 the vagus and sympathetic nerves in the thorax. 



THE ABDOMINAL CAVITY. 



As the remaining parts of the digestive system lie within the abdomen it will 

 be necessary to describe that cavity, and to refer briefly to its lining membrane 

 the peritoneum before passing on to the consideration of the viscera which are 

 contained within it. 



The abdomen is that portion of the trunk which lies below the diaphragm. It 

 consists of a wall, composed in part of bones, muscles, tendons, fascia, etc., enclosing 

 a large cavity, in which lie the greater part of the digestive, urinary, and generative 

 systems of organs, as well as blood-vessels, nerves, and other structures. The greater 

 part of the wall of the cavity, and the surfaces of the viscera, are clothed by a 

 continuous smooth membrane, the peritoneum. The cavity is completely filled by the 

 'organs mentioned. They lie in contact with one another, and when they are in situ 

 ' the so-called cavity is merely a potential space between the peritoneal surfaces of 

 adjacent viscera. When air is admitted, as, for instance, by opening the abdominal 

 ( wall in any place, the viscera fall away from one another and a space is formed, in 

 , place of the capillary interval which exists under normal conditions between them. 



In the following description, the term abdomen or abdominal cavity is used to 

 .indicate the region enclosed by the muscular and bony walls, and the term 

 peritoneal cavity the potential space inside the peritoneal membrane between the 

 viscera. 



Shape. In general shape the cavity is of a somewhat oval form, with the 

 long axis directed vertically. The superior end is wider than the inferior. It is 

 strongly flattened from before backwards, and is encroached upon in the median 

 plane posteriorly by the projection forwards of the vertebral column. 



On transverse section, it will be noticed that the front of the vertebral column 

 lies at no great distance from the back of the anterior abdominal wall (usually 

 2J- to 3 inches), while on each side of the vertebral column there is a deep recess, 

 3ccupied by the kidneys and portions of the intestine. 



The abdominal cavity is divisible into the abdominal cavity proper and the 

 pelvis minor. Vertical section of the trunk shows that the pelvis minor (O.T. true 

 pelvis) lies below and behind the abdominal cavity, of which it forms a funnel-shaped 

 termination. The long axis of the funnel is directed downwards and backwards. 



As the walls of these two regions are markedly different, the boundaries will be 

 Considered separately. 



Boundaries of the Abdomen Proper. The cavity is limited above by the concave 

 vault of the diaphragm, which is dome-shaped and presents a right and a left cupola 



