CLECUM AND VERMIFORM PEOCESS. 



1213 



Nerves. The nerves come from the superior mesenteric plexus, an offshoot of the coeliac 

 plexus, and from the inferior mesenteric, a derivative of the aortic plexus. The arrangement is 

 similar to that of the nerves of the small intestine. 



INTESTINUM (LECUM AND PROCESSUS VERMIFORMIS. 



Intestinum Caecum. After leaving the pelvic cavity, as already described, 

 terminal portion of the small intestine passes upwards, backwards, and to 

 right, and opens, by the ileo- 

 csecal orifice, into the large in- 

 testine some 2J inches from its 

 lower end. The portion of the 

 large gut which lies below the 

 level of this orifice is known as 

 the intestinum caecum. In shape 

 (Fig. 951) it is a wide, asym- 

 metrical, or lop-sided cul-de-sac, 

 furnished with the tsenise and 

 sacculations usually found in the 

 large intestine. Its lower end 

 o? fundus is directed downwards 

 and medially, and usually rests 

 on the right psoas major muscle, 

 close to the brim of the pelvis ; 

 whilst the opposite end is 

 directed upwards and laterally, 

 and is continued into the ascend- 

 ing colon. 



the 

 the 



Colon ascendena 

 A. ileocolica 



Plica ileocsecalis 

 Fossa ileo- 

 ctucalis 



Pelvic colon 

 Mesenteriolum 

 proc. verm. 

 Processus 

 vermiformis 



Vesica urinaria 

 Urachus 



FIG. 951. THE C^CUM AND VERMIFORM PIIOCESS FROM THE FRONT. 



Its asymmetrical form is due to the 

 fact that the lateral and medial por- 

 tions of the organ undergo an unequal 



development in the child. The medial (or medial and posterior) section lags behind, whilst the 

 lateral (or lateral and anterior) division grows much more rapidly, and, projecting downwards, 

 soon comes to form the inferior end or fundus of the caecum. As a result the original extremity 

 of the giit, with the vermiform process springing from it, is hidden away behind and to the 

 medial side of the fundus. 



In length the distended csecum usually measures about 2J inches (60 mm.) ; 

 whilst its breadth is usually more, and averages about 3 inches (75 mm.). 



Position. It is usually situated almost entirely within the right iliac 

 region of the abdomen, immediately above the lateral half or third of the inguinal 

 ligament ; but its inferior end projects medially in front of the psoas major and 

 reaches the hypogastrium (Fig. 951). On the other hand, it is sometimes found 

 high up in the right lumbar region (owing to the persistence of the foetal position), or 

 hanging over the pelvic brim and dipping into the pelvic cavity to a varying extent. 



In the great majority of cases the csecum is completely covered with peri- 

 toneum on all aspects, and lies quite free in the abdominal cavity. In a 

 small proportion, namely, about 6 or 7 per cent, of bodies, the posterior surface 

 (probably as a result of adhesions) is not completely covered, but over a 

 greater or less portion of its extent is bound down to the posterior abdominal 

 wall by connective tissue. 



Relations. Posteriorly, the csecum rests on the ilio-psoas muscle ; generally, too, 

 on the vermiform process and the femoral nerve. Anteriorly, it usually lies in 

 contact with the omentum and anterior abdominal wall ; but when the csecum 

 is empty, the small intestine intervenes. Its lateral side is placed immediately 

 above the lateral half or third of the inguinal ligament (Fig. 951), whilst the medial 

 side has the termination of the ileum lying in contact with it. On the medial 

 and posterior aspect, but more on the former than the latter, the small intestine 

 joins the csecum. On the same aspect, and usually from 1 to 1J inches (25 to 

 37 mm.) lower down, the vermiform process comes off. 



