1000 



THE ORGANS OF DIOESTIOX 



represents the ori<;iiial attaehment of the ])riuntiv(^ median fold. All other lines 

 of reflexion must l)e regarded us acquired or secondarv. 



The meso-gaster. — It now remains to consider what becomes of the upper 

 part of the simple primitive fold of peritoneum — the meso-gaster (m-g, tig. 598). 



The stomach enlarges, assumes more of its characteristic outline, and becomes 

 less vertical. 



The liver may be regarded as an outgrowth from the duodenum. Its connec- 

 tions with the great veins of the heart cause it to extend upwards and to the right 

 side. As it grows it se])arates the layers of the highest part of the peritoneal fold, 

 and from this memljrane it receives a covei'ing. The remains of the primitive 

 mesial fold persist in the form of tlie falciform ligament (tigs. 593, 595, and 599). 



The gastro-hepatic omentum. — The connection of the liver to the stomach is 

 intimate, partly througli the association of the great gland Avith the duodenum, and 

 partly through certain blood-vessels which pass to the stomach and liver from the 

 aorta. As the stomach enlarges, its duodenal end is drawn towards the right side; 

 the viscus becomes transverse, the left wall becomes anterior, and the right poste- 

 rior. The layer of peritoneum which stretches between the two organs is called the 

 gastro-hepatic or lesser omentum. The right or free margin of this omentum was 



Fig. 600. — Diageabi to show the Formation of the Great Omextum. 



qastro-}ie]iat. om 



ME50- 

 W7 RECTUM 



originally anterior, and the whole fold is directly derived, with but little dis- 

 turbance of the membrane, from the upper part of the primitive meso-gaster (figs. 

 593, 595). 



The great omentum. — The formation and disposition of the great omentum 

 are a little ditticult to follow in the adult human species, and the student's concep- 

 tion of the right character of this fold may l)e a little distorted by a study of certain 

 diagrams which show the omentum from one point of view only. In mammals and 

 in the human fo'tus the dis})osition of the great omentum is readily appreciated. 



This fold ai)pears as a bulging of the meso-gaster forwards and to the left. 

 When the stomach has assumed its final position, this bulging of the membrane is 

 of course entirely in the direction forwards. 



At first the great omentum forms a shallow and wide-mouthed bag. Its appear- 

 ance is such as could be produced in imagination if the fingers were to be pressed 

 against the right (pf)sterior ) side of the meso-gaster, and were to force a l)ag of the 

 yielding membrane Ijeforethem. The pendulous bag-like projection could be seen 

 from th(^ left side of the "meso-gaster and the wide opening into the V)ag from the 

 right (tig. ()00). Here the bag is re})resented as cut away. An arrow passing from 

 right to left, i.e., from behind forwards, shows the direction of the ])r()trusion. 



