ABDOMEN AND PELVIS 



463 



The following folds of peritoneum, connecting the intestinal tract with 

 the anterior and posterior abdominal walls, should be noted (cf. Fig. 241) : 



(a) Ventral mesentery (mesenterium anterius). What is its extent? 



(b) Dorsal mesentery (mesenterium posterius). Note its extent and 



divisions. 



Note that, while these structures are found in the embryo, they 

 persist in part in different forms and relations in the adult. 



(c) Duodenal loop (ansa duodenalis). 



FIG. 241. 



Ramus hepaticus 

 Ramus coronarius 

 A. gastrica sinistra 

 A. lienalis 



A . gastro-epiploica sin. 



A. codiaca 



A. hepatica 



A. gastrica dextra 



A. gastro-epiploica dextra 



A. hepatica propria 



A. pancreaticodaod. sup. 



A. mesenterica sup. 



Aorta 



Aa. intestinales 



A. colica dextra 



A. mesenterica inferior 



Oesophagus 



Diaphragma 

 Cardia 



A. haemorrhoid. sup. 

 A. sacralis media 



Ventriculus 



Omentum minus 



Hepar 



Lig. falciforme hepatis 



Ant. abdom. wall 



Pylorus 



Duodenum 



Descending limb of the 

 ansa umbilicalis 



Ascending limb of the ansa 



umbilicalis 

 Vitelline duct 



Intestinum terminate 



Primitive mesovesica 

 Pedicle of the allantois 



Cloaca and anus 



Schematic section of the abdomen of an embryo in which the segments of the alimentary canal 

 have been differentiated. The section is made in the sagittal plane and is to the right of the median 

 plane. The right face of the mesenterium commune dorsale and of the mesenterium ventrale is shown. 

 The liver is represented isolated from the anterior abdominal wall and the diaphragm. Star with 8 

 points, territory of the A. coeliaca ; star with 6 points, territory of the A. mes. sup. ; star with 4 points, 

 territory of the A. mes. inf. ; 1, 2, 3, Aa. colicae dextra, media et sinistra ; g, m, d, Aa. sigmoideae ; 

 cross, mesenterium ventrale. (From Fredet in Poirier et Charpy, Traits d'Anat. hum., Paris, 1901, 

 2 ed., t. iv. p. 881, Fig. 455.) 



(d) Intestinal loop (ansa intestinalis or umbilicalis). The summit of 

 this ansa is in communication with the vitelline duct and 

 this determines its convexity anteriorly. This ansa is 

 divided into two segments: 



(da) Superior descending or proximate segment, forming an 



obtuse angle with the ansa duodenalis (flexura duodeno- 

 jejunalis of the embryo). 



(db) Inferior or ascending segment. This is prolonged to the 



