THE (ESOPHAGUS. THE ABDOMEX. 823 



Minute papillae are seen upon this mucous membrane, placed at some 

 distance from each other, and the whole is covered with a thick squamous 

 epithelium, which can be traced as far as the cardiac orifice of the stomach, 

 where it suddenly passes into one of a different character, as will be here- 

 after noticed. 



The gullet is provided with many small compound racemose glands, named 

 cesophageal glands, which are especially numerous at the lower end of the 

 tube. 



Dilatations occasionally occur in the course of the oesophagus. Diverticular pouches 

 are also sometimes found, but appear in all cases to be of hernial origin. Duplicity 

 of the oesophagus in part of its extent, without other abnormality, has been recorded 

 (Blaes, quoted by Meckel). 



THE ABDOMINAL PORTION OF THE DIGESIIVE OEGANS. 



As that part of the digestive canal which is found beneath the diaphragm, 

 and consists of the stomach and intestines, is situated within the cavity 

 of the abdomen, and occupies, together with the liver (the secretion of 

 which it receives), by far the greater part of that cavity, the topographic 

 relations of the abdominal viscera may here be briefly explained. 



THE ABDOMEN. 



The abdomen is the largest cavity in the body, and is lined by an exten- 

 sive and complicated serous membrane, named the peritoneum. 



It extends from the diaphragm above to the levatores ani muscles 

 below, and is subdivided into two parts : an upper and larger part, the 

 abdomen, properly so called ; and a lower part, named the pelvic cavity. 

 The limits between the abdominal and pelvic portions of the cavity are 

 marked by the brim of the pelvis. 



The enclosing Avails of this cavity are formed principally of muscles and 

 tendons which have been already described (p. 248). They are strengthened 

 internally by a layer of fibrous tissue lying between the muscles and the 

 peritoneum, the different parts of which are described under the names 

 of fascia transversalis, fascia iliaca, and anterior lumbar fascia (p. 257). 

 These walls are pierced by several apertures, through which are transmitted 

 the great vessels and some other parts, such as the several diaphragmatic 

 apertures for the aorta, vena cava, and oesophagus, and the femoral arches 

 and inguinal canals. In the median fibrous substance of the anterior wall 

 lies the umbilical cicatrix. The cavity of the pelvis is also lined with strong 

 fasciae (p. 260), and partially by peritoneum, and at its lower part it presents 

 the apertures for the transmission of the rectum and the genito-urinary 

 passages. 



For the purpose of enabling precise reference to be made to the situation 

 and condition of the contained organs, the abdomen proper has been arti- 

 ficially subdivided into certain regions, the boundaries of which are indicated 

 by lines drawn upon the surface of the body. Thus, two horizontal lines 

 drawn round the body divide the cavity into three zones : viz. an upper, a 

 middle, and a lower. One of these lines, commencing at the most prominent 

 point of the lower costal cartilages of one side, is drawn across to the cor- 

 responding point on the opposite side, and thence horizontally round the 

 back to the place at which it began. The other line, proceeding from the 

 crest of the ilium of one side, extends to that of the other, and so round the 

 body, as in the former instance. Each of these zones again is subdivided 



