2 5 o PRACTICAL ANATOMY. 



6. The round ligament of the liver, you will remember, extends from the 

 umbilicus to the liver. It is in the free border of the broad ligament of the liver. 

 It is the fuetal remains of the umbilical vein. (Fig. 176.) You will remember 

 that in the child before birth, the placenta purifies the blood, as do the lungs, 

 after birth. The blood is taken in an impure state to the placenta by the hypogas- 

 tric arteries, and returned pure by the umbilical vein. (Fig. 15 5-) 



7. Tlircc amenta are the gastro-hepatic, or small ; the gastro-colic, or great ; 

 the gastro-splenic. You learned to define omentum as peritoneal folds connect- 

 ing organ to organ. In your dissection you saw the great omentum as a heavy, 

 fatty veil, covering in all the small intestine, and hanging down even into the true 

 pelvis. This may even become a hernia, an amentocelc, and appear at any one 

 of the four fossae described in the foregoing review. 



8. The Colon and Its Subdivisions ( Fig. 175). The point where differentiation 

 takes place is usually in the right iliac fossa ; still, it may occur above this point. 

 You will see on your work two flexures in the colon the hepatic, at the lower 

 margin of the right lobe of the liver ; the splenic, at the lower margin of the 

 spleen. The transverse colon lies between these two flexures. The descending 

 colon is below the splenic ; the ascending, below the hepatic flexure. 



9. You will examine and recall the nature of the colic attachments. That of 

 the ascending, and also of the descending, is in the nature of one structure 

 adherent to another ; their meso-colons, in other words, are short ; hence you 

 are not able to move them freely from place to place, as you can move the 

 transverse colon. On the other hand, the meso-colon of the transverse colon is 

 very long, due to which fact the transverse is the most movable part of the 

 colon. Also recall the definition for mesentery : peritoneal folds binding organ 

 to wall. The meso-sigmoid is also long. 



10. Diagnostic of large intestine, you will remember, are the three longitudinal 

 muscular bands of fibres ; the consequent sacculations produced by these ; the 

 fatty masses called appendices epiploica. The latter are variable in size ; in one 

 case they may be very large, in another quite small ; they are always present 

 on large intestine. Any one of the three bands will lead to the appendix. 



1 1. As you will remember, you inflated the duodenum and studied the third 

 part of this organ as it passed behind the superior mesenteric vessels. The 

 remaining part of the small intestine is arbitrarily divided into an upper two-fifths, 

 called jejunum, and a lower three-fifths, called ileum. Jejunum means empty or 

 hungry, and ileum means coiled. There is no practical histological difference 

 between the two. They are held by their mesentery to a line extending from the 

 left side of the body of the second lumbar vertebra, to the right sacro-iliac 

 synchondrosis. In its course it lies upon, as you will presently see, the aorta, 

 vena cava inferior, transverse part of the duodenum, and vertebral column. You 

 will see, then, that the mesentery of the small intestine forms a partition between 

 the right iliac fossa and the true pelvis ; that fluid to the left of this partition 

 would be directed into the pelvis, to the right of the same, into the right iliac 

 fossa. Make this experiment. 



You will now, by dissection, analyze the following localities and structures : 



1. The foramen of Winslow. 



2. The root-structures of the liver. 



3. The lesser cavity of the peritoneum. 



4. The greater cavity of the peritoneum. 



5. The ascending, descending, and transverse duodenum. 



