J300 THE ORGANS OF DIGESTION 



tenderness in appendicitis. The origin of the appendix varies with the type of 

 cecum present. These variations are shown in Fig. 1036. The movable portion 

 of the appendix may be met with in different situations. It may pass upward and 

 in front of the cecum and colon, upward and behind the cecum, and even behind 

 the colon between the two layers of the mesocolon; upward and to the inner side 

 or upward and to the outer side of the cecum and colon. It may pass to the left 

 under the ileum and mesentery, upward and to the left or downward and to the left 

 into the true pelvis. It may pass directly downward under the cecum. It may 

 pass to the right in front of or back of the cecum. It may occupy any one o'f the 

 cecal fossae (p. 1267), but most often enters the ileocecal fossa. When the cecum 

 is mobile the appendix may be found almost anywhere within the abdomen. 

 When the cecum is undescended, the appendix of course shares in the failure to 

 descend, and may be below the gall-bladder or in front of the right kidney, and may 

 pass in several directions upward behind the cecum, to the left behind the ileum 

 and mesentery; or downward and inward into the true pelvis. It varies from one- 



ILEOCOLIC ARTERY 



ANTERIOR ILEO- 

 CECAL ARTERY 



ANTERIOR OECAL 

 ARTERY 



APPENDICULAR 

 ARTERY 



APPENDIX 

 VERMIFORMIS 



FIG. 1037. Arteries of the cecum and of the appendix vermiformis and of the terminal portion of the ileum. 



(Poirier and Charpy.) 



half an inch to nine inches in length (1.25 to 22.5 cm.) its average being about 

 three inches (7.5 cm.). Its diameter is from one-eighth inch to one-quarter inch 

 (3 to 6 mm.). The operating surgeon may occasionally fail to find an appendix 

 buried in one of the cecal fossae, and may conclude that the diverticulum is absent. 

 In rare instances the appendix has been found absent. It is retained in position 

 by a fold of peritoneum derived from the left leaf of the mesentery, which forms 

 a mesentery for it, and is called the mesoappendix (p. 1265 and Figs. 991 and 992). 

 This fold, in the majority of cases, is more or less triangular in shape, and, as a 

 rule, extends along the entire length of the tube. In color the healthy appendix 

 is yellowish-pink and is soft and smooth to the touch. The canal of the appendix 

 is small and extends throughout the whole length of the organ. The walls of the 

 healthy diverticulum are thick, and the diameter of the lumen is usually trivial 

 as compared with the diameter of the appendix itself. The lumen of the appendix 

 communicates with the cecum by an orifice which is placed below and behind the 

 ileocecal opening (Fig. 1042). It is sometimes guarded above and to the left side 

 by a semilunar fold of mucous membrane, the valve of Gerlach (valvula processus 

 vermiformis}. The valve is inconstant, and is never perfect. It is stated that 

 the lumen of the appendix tends to undergo obliteration as an involution change 

 in a functionless organ. The lumen rarely contains foreign bodies after death, 

 but often contains fecal concretions. Certain it is that in 25 per cent, of necropsies 

 upon adults or elderly people the lumen is found to be partially or completely 

 occluded. 



