THE ABDOMEN 



79-: 



Ileo-caecal or Ileo-colic Valve (valve of Tulpius). — This valve is 

 situated at the point where the terminal part of the ileum opens into 

 the junction between the caecum and ascending colon. The orifice, 

 as seen from the interior of the large intestine, has the form of a 

 slightly oblique cleft about h inch long, and rimning in an antero- 

 posterior direction. It is boimded above and below by the two 

 segments which form the valve, and which project into the large 

 intestine. The upper or ileo-colic segment is prominent, and occu- 

 pies an almost horizontal plane. The lower or ileo-ccecal segment, 

 longer than the upper, is concave superiorly, and occupies an oblique 

 plane. The anterior part of the cleft is rounded off, whilst the 



Ascending Colon 



Frenum of Ileo-caecal VaWe 



Frenum of IIeo-_, 

 caecal Valve 



Ileum 



Orifice of Vermiform ' 

 Appendix 



Venniform Appendix 



Pi^*- 343- — The Interior of the Cjecum and the Ileo-c^cal Valvk. 



posterior part tapers to a point. The segments meet in front of 

 and behind the cleft, and form two prominent folds, which are 

 prolonged round the wall of the bowel for some distance. These 

 folds are known as the frena or retinaciila of Morgagni. Each 

 segment is composed of two layers of mucous membrane, one of 

 which belongs to the ileum, and the other to the caecum or colon 

 as the case may be. These two layers are continuous with each 

 other at the free margin of the segment, and they contain between 

 them submucous areolar tissue and circular muscular fibres, both 

 of which are derived partly from the ileum and partly from the large 

 intestine. The longitudinal muscular fibres and the serous or 

 peritoneal coat take no part in the formation of the segments, 

 being continued uninterruptedly from the ileum to the large 



