PRACTICAL CONSIDERATIONS : THE LARGE INTESTINE. 1683 



to catarrhal enteritis, favoring the formation of concretions, or at least impairing 

 the protective power of the intestinal epithelium ; (b) the relatively greater length 

 of the appendix in young persons (in infants one-tenth and in adults one-twentieth 

 the length of the large intestine, according to Ribbert) increasing the difficulty of 

 drainage ; and possibly (c) the tendency to shrinkage or obliteration after middle 

 life, a process to be expected in a rudimentary organ. 



6. It must not be forgotten, in interpreting the foregoing anatomical facts as to 

 (a) the rudimentary character of the appendix, () the scantiness of its mesentery, 

 {c} its dependence for its blood-supply upon one vessel, (</') its imperfect drainage, 

 and (^) the profusion of its lymphoid tissue, that these are but predisposing causes 

 in most cases of serious appendix disease, and that the congestion, catarrh, distention, 

 or ulceration occasioned by them occurs invariably in the presence of micro-organ- 

 isms capable of great virulence, which exist in increased numbers in this portion of 

 the intestinal tract (page 1680), and which, as has been abundantly proved, are 

 ready to take on pathogenic action in the presence of either mechanical or chemical 

 irritation of the intestinal tissues, especially if there is deficient drainage of the early 

 products of such irritation or of the resultant inflammation. The proximity of the 

 appendix to areas of abdominal or pelvic infection, as in typhoid fever, intestinal 

 tuberculosis, dysentery, or salpingitis, is a factor of minor but definite importance. 



Anatomical Points relating to the Symptoms of Appendicitis. i. Pain. This is 

 at first general and diffused because the superior mesenteric plexus of the sympathetic, 

 which supplies the appendix, also largely supplies the intestines, and because irrita- 

 tive nerve-pain is apt to be referred to the peripheral extremities of nerves ; next and 

 within a very short time felt in the umbilical region, because as such pain increases 

 in intensity it is often referred to the nearest nerve-centre, and the great sympathetic 

 ganglia of the abdomen are situated in proximity to that region. 



At this time the pain is often colicky in nature, and a discussion has arisen as to 

 whether or not the circular muscular fibres in the appendix are of sufficient strength 

 to cause it. The question seems unimportant, as appendix irritation may result in 

 colicky spasm of neighboring portions of either small or large intestine. The pain of 

 the later stages of appendicitis may be partly due to peritoneal swelling causing 

 traction upon the peritoneal attachments. 



2. Tenderness. After a few hours the pain is felt in the right iliac fossa, 

 because it has then become a neuritis of sufficient grade to cause tenderness on press- 

 ure. It is localized tenderness in all the varieties of appendicitis, because, while the 

 appendix itself is movable, it always arises from the same part of the caecum, and 

 the mobility of the latter is more restricted. The point of pain on pressure indicates, 

 therefore, with moderate accuracy, the base, not the tip, of the appendix, and is 

 rarely absent even in gangrenous cases, because that portion of the appendix is 

 usually the last to be affected by interference with the blood-supply. This point 

 is where the omphalo-spinous line (drawn from the umbilicus to the anterior superior 

 iliac spine) meets the outer border of the rectus, or a point on that line from 5-7.5 

 cm. (2-3 in.) from the iliac spine (McBurney's point). In the majority of instances 

 the base of the appendix lies beneath a circle two inches in diameter, having this 

 point as its centre. Its situation must obviously vary with that of the caecum and is 

 not uncommonly lower, i. c. on the interspinous line. Undue diagnostic value has 

 been placed upon tenderness at this precise position. The chief tenderness may be 

 lumbar if the appendix is post-caecal in position, or close to Poupart's ligament or to 

 the median line, or best elicited by rectal touch if the appendix lies in the pelvis. 



3. Rigidity of the right rectus m^lscle, and later of the other abdominal muscles 

 over the right iliac fossa, is often, but perhaps not necessarily, due to peritonitis, 

 and in any event arises from the fact that those muscles receive their nerve-supply 

 partially from the six lower intercostals, while the superior mesenteric plexus gets 

 its contribution from the spinal system through the splanchnics, derived from some 

 of the same intercostals. 



4. Vomiting commonly follows, has little relation to gastric conditions, is ordi- 

 narily reflex and due to reversed peristalsis, and is apt to be associated with moderate 

 fever and slightly increased pulse-rate due to autotoxaemia. 



Other and later symptoms are mentioned in the next section. 



