ABDOMINAL CAVITY 331 



with peritoneum, and is supplied with blood by branches 

 derived from the loop between the termination of the superior 

 mesenteric artery and its ileo-colic branch. 



Processus Vermiformis (O.T. Vermiform Appendix). The 

 vermiform process springs from the medial and posterior 

 aspect of the caecum, about 25 mm. (i inch) below the ileo- 

 crecal junction. It passes either upwards and to the left, 

 towards the left hypochondrium, or downwards into the pelvis 

 minor, across the right external iliac artery, or upwards behind 



Frenulum of valv 



Anterior taenia coli 



Upper segment 

 of valve 



Frenulum of valv 



Orifice of ileum 



Inferior segment 

 of valve 



Ileum 



Orifice of vermiform process 



FIG. 153. Caecum which has been distended with air and dried, and then 

 opened to show Ileo-Caecal Opening and Colic Valve. (Birmingham.) 



the caecum and the ascending colon. It usually occupies the 

 last position if a retro-colic pouch is present. It is attached, 

 by the mesentery of the vermiform process, to the posterior 

 surface of the lower part of the mesentery of the ileum. 



Dissection. Turn the caecum upwards ; remove the peri- 

 toneum from the wall of the iliac fossa behind it, and take away 

 the extra-peritoneal fat. Note that the peritoneum and fat 

 separate the caecum from the right psoas and iliacus muscles, 

 and from the femoral nerve (O.T. anterior crural) which lies in 

 the angle between the muscles. The anterior surface of the 

 caecum is in relation with the anterior wall of the abdomen, or is 

 separated from it by the lower part of the greater omentum. 



Cut away a portion of the right lateral wall of the caecum 

 and examine the ileo-caecal orifice and the orifice of the vermi- 

 form process from the interior of the intestine. 



