THE CHCUM AND APPENDIX. 1029 
breadth as } inch (6 mim., Berry). On the other hand, it has been found as long as 
9 inches (250 muin.), and as short as ?} inch (18 mm.). Even its absence has been 
recorded (Fawcett). 
Its /wmen 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, which is by many 
considered to be undergoing a gradual obliteration in the human_ species. 
It opens into the cavity of the cecum on its inner, or inner and posterior aspect 
(Fig. 693), at a point 1 to 12 inches (2°5 to 3-8 em.) below, and somewhat behind 
the ileo-czecal orifice. These are the relative positions of the two orifices, as seen 
from the interior, of the cecum; viewed from the exterior, the base of the appendix 
is within ? inch of the lower border of the ileum. This apparent difference is due 
to the fact that the ileum adheres to the inner side of the cecum for a distance of 
nearly 1 inch before it opens into it. 
Sometimes the orifice of the appendix has a crescentic fold or valve (valvula 
processus vermiformis) placed at its upper border; but 1t is probably of very little 
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Fic. 696.—THE BLOOD SUPPLY OF THE C#CUM AND VERMIFORM APPENDIX. 
The illustration to the left gives a front view, in that to the right the cecum is viewed from behind. In the 
latter the artery of the appendix, and the three tenia coli springing from the base of the appendix, 
should be specially noted (modified from Jonnesco). 
functional importance when present, for the aperture of the appendix is usually so 
small that its cavity is not likely to be invaded by the contents of the cecum. 
The vermiform process is completely covered by peritoneum, and has a con- 
siderable mesentery, the meso-appendia (mesenteriolum processus vermiformis), 
which extends to its tip as a rule, and connects the process to the under surface of 
that part of the mesentery proper which goes to the lower end of the ileum. 
The appendix 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 shghtly 
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 
of those over 60 years old, whilst it is unknown in the child. This frequency of occlusion, the 
physiological atrophy which takes place after middle life, the great variations in length, and other 
signs of instability, have been considered to point to the retrogressive character of the appendix. 
A vermiform process is found only in man, the higher apes, and the wombat, although in 
certain rodents a somewhat similar arrangement exists. In carnivorous animals the caecum is very 
slightly developed ; in herbivorous animals (with a simple stomach) it is, as a rule, extremely large. 
It has been suggested that the vermiform process in man is the degenerated remains of the 
herbivorous cecum, which has been replaced by the carnivorous form. Another and perhaps 
more probable view regards the appendix as a lymphoid organ, having the same functions as 
Peyer’s patches, and like these undergoing degeneration after middle life (Berry). 
