THE PERITONEUM 



m\ 



Varieties. — Tlic jn-incipal iK-ouliarity is due to the presence of supplementary 

 spleens (lieneuli), found in tlie u;astro-splenic omentum, or less often in the jrreat 

 omentum. From one to twenty of these small l)odies may he met with. They 

 are red and n^und, of the same structure as the spleen, and vary in size from a ]i('a 

 to a walnut. 



Structure. — Bene-atli the eoverinj^ of ])eritoneum is a thin but tough aipMik of 

 areolar tissue, ealh'd tlie tunica propria, which is very adherent to the serous mem- 

 brane. It is remarkably elastic. It sends a jjrolongation in at the hilum, which 

 follows and sup})orts the vessels to their termination. Within the ea])sule is the 

 •pulp. This is a very soft frialile tissue of a dark reddish-brown color, not unlike 

 grumous blood in color and consistence. It can be squeezed out from the cut 

 s{)leen, and then it will lie seen that the whole organ is pervaded by a network of 

 tine fibres which support the pulp. The larger of these come off directly from tlie 

 fibrous capsule, and are called trabecule. 



In* Front. 

 Stomach ; splenic flexure of colon. 



Outer Side. 



Diaphragm ; ninth to eleventh 

 ribs between axillary line. 



GENERAL RELATIONS 



OF 



THE SPLEEN 



Inner Ride. 



Stomach; pancreas; left kidney 

 and capsule. 



Behind. 

 Diaphragm. 



Blood-supply. — The si^leen receives its lilood from the splenic artery, which is 

 very large in i)roportion to the body it is going to supply. It divides before 

 entering into about six branches. The artery is very tortuous. The vein, on tiie 

 other hand, is straight, and lies below the artery. 



. The lymphatics are divided into a superficial and a deep set. The former 

 forms a ])lexus beneath the peritoneum. The latter are derived from fine peri- 

 vascular spaces in the adenoid tissue around the vessels. They join at tlie hilum, 

 and ])ass l)etween the layers of the gastro-hepatic omentum to the glands in that 

 neighI)ourliood. 



The nerves are from the solar plexus. They pass in along the splenic artery. 



THE EVOLUTION OF THE PERITONEUM AND AX EXPLANATION 

 OF ITS ARRANGEMEXT IX THE HUMAX BODY 



The peritoneum is a serous membrane, and is identical with other like-named 

 membranes which are less complicated in their disposition. It differs in no 

 essential ])articular from the ])leura. from the pericardium. fr<jm the tunica vagi- 

 nalis, from the synovial mend)rane of a joint, or from the simph' vaginal sheath of 

 a tendon. In all there is practically a closed sac of thin membrane, which is so 

 disposed as to both line a cavity and to invest the structures which encroach upon 

 tiiat cavity. 



Imagine a pleiu'al cavity from which the lung ha<l vanished without disturbance 

 of parts. The membrane lining it would ajtpear as a simjjle ser<»us bag. Xext 

 conceive the lung gradually budiling towards tliis sac. It would ]»usli the mem- 

 l>rane before it, and as it did so it would both encroach upon the cavity lined liy 

 the mend)rane, and be itself covered or invested l»y it. 



AVhen the lung had attained nearly to the dimensions of the rigid cavity it was 

 occupying, the serous lining would i)e found to invest the whole of it exce]>ting 

 only its pedich — tlie stalk of the original bud — the root of tlie lung. 



