THE GFCUM 



1303 



of the large intestine (Fig. 1043), the invaginated portion of the wall of the small 

 intestine uniting with a corresponding portion of the wall of the large intestine. 

 Each segment of the valve is formed by a reduplication of the mucous membrane 

 and of the circular muscle fibres of the intestine, the longitudinal fibres and peri- 

 toneum being continued uninterruptedly 

 across the one portion of the intestine to 

 the other. 



The surface of each segment of the 

 valve directed toward the ileum possesses 

 villi, and presents the characteristic 

 structure of the mucous membrane of the 



ORIFICE OF 

 APPENDIX 



FIG. 1042. Ileocecal valve of the circular type. 

 (Poirier.) 



FIG. 1043. Vertical section through the cecum and 

 ileocecal valve. (Gegenbaur.) 



small intestine; while that turned toward the large intestine is destitute of villi, 

 and marked with the orifices of the numerous tubular glands peculiar to the mucous 

 membrane of the large intestine. These differences in structure continue as far 

 as the free margins of the 

 valve. When the cecum is 

 distended it is supposed that 

 the margins of the opening 

 are approximated so as to 

 prevent reflux into the ileum. 

 It is known, however, that a 

 very large enema which dis- 

 tends the cecum and colon 

 may in part enter the ileum, 

 being driven there by waves 

 of reversed peristalsis. The 

 valve resists, but a certain 

 amount of pressure over- 

 comes it. Some believe that 

 the so-called ileocecal valve 

 is not a valve, but a distinct 

 sphincter. This has been 

 demonstrated to be true in 

 cats and dogs, but lacks dem- 

 onstration in man (p. 1314). 



Applied Anatomy. The vermiform appendix is very liable to become inflamed, the condi- 

 tion being known as appendicitis. The condition may be set up by a catarrhal inflammation 

 arising in the appendix or derived from the colon. It may remain catarrhal and then subside. 

 It may become purulent or may be purulent from the beginning. Anything which lessens vital 



SUPERIOR 

 SEGMENT 



INFERIOR 

 SEGMENT 



LONG MUSCU- 

 LAR FIBRES 

 FROM ILEUM 



ANTERIOR 



T/ENIA 



CUL-DE-SAC 

 OF CECUM 



POSTERIOR 



TXENIA 



FIG. 1044. Cecum and vermiform appendix; ileum cut through. 

 (Sappey.) 



