DISSECTION OF THE DOG 



21 



right colic flexure (flexura coli dextra) ; (2) the second part of the colon, the 

 transverse colon (colon transversum) , like the first, is generally very short. It 

 crosses the median plane immediately cranial to the root of the mesentery, and, 

 arriving on the left side of the abdomen, curves in a caudal direction at the left 

 colic flexure (flexura coli sinistra) ; (3) the descending colon (colon descendens) 



Vena cava caudaZis 



m. Uio-coslcUis 



m. obliquus 

 abdominis internus- 



m. obliquus 

 abdominis externus' 



m. transversus abdominis 



Colon descendens^ 



Colon ascendens 



m. rectus abdominis 



Duodenum 



3?ig. 6. — Transverse section through the abdomen on a level with the first lumbar 

 vertebra. Sections of small intestine are not named. 



forms by far the greater part of the whole tube. In order to expose it, it is neces- 

 sary to turn the mass of small intestine over to the right. The descending colon 

 will then be revealed to the left of the median plane in the form of a fairly 

 straight tube running towards the pelvis from the left colic flexure. On approach- 

 ing the pelvis, a gradual slope towards the right causes the intestine to disappear 

 into the pelvic cavity about the middle line. In the female the colon gains the 

 pelvis by passing dorsal to the uterus ; in the male, dorsal to the urinary bladder. 



c 3 



