1026 THE DIGESTIVE SYSTEM. 
behind, whilst the outer (or outer and anterior) division grows much more rapidly, and, pro- 
jecting downwards, soon comes to form the lower end or fundus of the cecum. As a result the 
original extremity of the gut, W ith the vermiform process springing from it, is hidden away 
behind and to the inner side of the fundus. 
Dal 
“9 
In length the distended cecum usually measures about inches (60 mm.); 
whilst its breadth is usually more, and averages about 3 inches (75 mm. ). 
Position.—It is situated, when ities almost entirely within the right ilae 
region of the abdomen, immediately above Poupart’s ligament; but its lower end 
projects inwards in front of the psoas and reaches the hypogastrium (Fig. 699). 
On the other hand, it is sometimes found, even when quite healthy, 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 varying extents. 
In the great majority of cases the 
cecum 1s completely covered by peri- 
toneum on all aspects, and lies quite 
Upper 
segment 
of valve 
Orifice of 
valve free in the abdominal cavity. Ina 
ister small proportion, namely, about 6 or 7 
segment per cent of bodies, the posterior surface 
Frenulum 
of valve 
(probably as a result of adhesions) is 
en not completely covered, but over a 
passed ereater or less portion of its extent is 
through 
orifice of 
hound down to the posterior abdominal 
Ee wall by connective tissue. 
Relations.—Aehind, the czecum rests 
on the ilio-psoas muscle; generally, too, 
: on its own vermiform process and the 
Upper 5 
segment” external iliac artery. In front, it 
Orifice usually les im contact with the anterior 
Frenulum————— abdominal wall; sometimes, however, 
when the cecum is empty, the small 
intestine intervenes. Its outer side is 
placed immediately above the outer half 
of Poupart’s ligament (Fig. 699), whilst 
the inner side has the termination of the 
ileum lying in contact with it. On the 
inner and posterior aspeet, but more on 
the former than the latter, the small 
intestine joins the cecum. On _ the 
same aspect, and usually about 14 inches 
(31 mm.) lower down, the vermiform 
process comes off. 
The interior of the cecum corre- 
sponds in general appearance to that 
of the large intestine; but it presents 
two special features on the posterior 
part of its inner wall, namely, the ileo- 
cecal orifice, guarded by the ileo-cecal 
valve, and below this the small opening 
of the vermiform appendix, both of which 
Lower 
seginent 
Orifice of 
appendix 
Upper Dos 
segment — 
Oritice—— 
Lower 
Segment ~—_| 
Orifice of 
appendix ~ 
Fic. 694.—THREE ForMs oF ILEO-caCAL VALVE, from 
bodies hardenel by intravascular 
formalin, 
The hardening was not so complete in the case of the 
highest of the three valves represented. In each 
a bristle is passed through the orifice of the vermi- 
form appendix. 
injec tions of 
eall for further notice. 
Tleo-cecal Valve (valvula coli).— 
Where the ileum enters the large in- 
testine, the end of the small out ig.as 
it were, thrust through the wall of the 
large bowel, carrying with it certain 
layers of that wall, which project into the cecum in the form of two folds, lying 
respectively above and below its orifice, and constituting the two segments of the 
ileo-ceecal valve (Fig. 695). 
The condition may be compared to a partial inversion 
a 
