1216 THE DIGESTIVE SYSTEM. 



has been found in almost every possible situation in the abdomen which its length 

 and the extent of its mesentery would allow it to attain. In every case the 

 anterior taenia of the caecum, which is always distinct, offers the surest guide to 

 the vermiform process, and its base can be located with certainty by following 

 this taenia to the back of the caecum (Fig. 954). 



Its size is almost as variable as its position. Taking the average of numerous 

 measurements, its length may be given as about 3J inches (92 mm., Berry), and 

 its breadth as J inch (6 mm., Berry). On the other hand, it has been found as 

 long as 9 inches (230 mm.), and as short as f inch (18 mm.). Even its absence 

 has been recorded (Fawcett), but this must be looked upon as an extremely rare 

 occurrence. 



Its lumen or cavity is variable in its development, and is found to be totally 

 or partially occluded in at least one-fourth of all adult and old bodies examined. 

 This is looked upon as a sign of degeneracy in the process of gradual oblitera- 

 tion, which it is by many considered to be undergoing, in the human species. It 

 opens into the cavity of the caecum on its medial, or medial and posterior aspect 



ANT 

 GAECAL 



FIG. 954. THE BLOOD-SUPPLY OP THE C^CUM AND VERMIFORM PROCESS. 



The illustration to the left gives a front view ; in that to the right the caecum is viewed from behind. In the 

 latter the artery of the process, and three taeniae coli springing from the base of the vermiform process 

 should be specially noted. (Modified from Jonnesco). 



(Fig. 952), at a point 1 to 1 inches (2*5 to 3*8 cm.) below, and somewhat posterior to 

 the ileo-caecal orifice. These are the relative positions of the two orifices, as seen 

 from the interior of the caecum ; viewed from the exterior, the base of the vermiform 

 process is within f inch of the lower border of the ileum. This apparent difference 

 is due to the fact that the ileum adheres to the medial side of the caecum for a 

 distance of nearly 1 inch before it opens into it. 



Sometimes the orifice of the vermiform process has a crescentic fold or valve, 

 the valvula processus vermiformis, placed at its superior border ; but it is probably of 

 very little functional importance, for the aperture of the process is usually so 

 small that its cavity is not likely to be invaded by the contents of the caecum. 



The vermiform process is completely covered with peritoneum, and has a con- 

 siderable mesentery, the mesenteriolum processus vermiformis (O.T. meso-appendix), 

 which extends to its tip as a rule, and connects the process to the inferior surface of 

 that part of the mesentery proper which goes to the inferior extremity of the ileum. 



The vermiform process is relatively, to the rest of the large intestine, longer in the child at 

 birth than in the adult, the proportion being about 1 to 16 or 17 at birth and 1 to 19 or 20 in 

 the adult. (The difference is certainly not as great as stated by Ribbert, who makes the 

 proportion 1 to 10 at birth and 1 to 20 in the adult.) The process attains its greatest length and 

 diameter during adult and middle age, and atrophies slowly after that time. It is said to be 

 slightly longer in the male than in the female. 



Total occlusion of its cavity is found in 3 or 4 per cent, of bodies ; it is then converted into a 

 fibrous cord. Partial occlusion is present in 25 per cent, of all cases, and in more than 50 per cent. 



