Practium IV. The Peritoneum. 25 



e. If time and opportunity permit, compare with the human diaphragm as seen in 

 the manikin, the wax model, and the preparations of young individuals. 



5. Opening the Abdomen. Place the specimen on its right side. 

 Compare with Plates II and IX. At about the middle of the abdomen 

 (pbQ\\\.\\\t N of ABDOMEN \VL PI. 2) pinch up a fold and slit for 2-3 

 cm. (about one inch). With the scissors cut thence, without wounding or 

 displacing the viscera, to about i cm. of the meson ; thence cephalad to 

 about the same distance of the diaphragm ; thence along it to near the 

 spinal muscles. Return to the meson and cut thence to the pelvis and 

 dorsad to the spinal muscles. The flap of abdominal parieles may then 

 be turned dorsad. 



a. The best instrument for dividing the abdominal wall without cutting the viscera 

 is a probe-pointed bistoury. 



6. The Peritoneum. Note that the ental surface consists of a 

 smooth serosa, the PERITONEUM ; also that there are recognizable at least 

 two layers of muscle, the fibers of the ectal having the direction indicated 

 in PI. 2, those of the next layer extending caudo-laterad at an acute 

 angle with them, i. e., nearly parallel with the fibers of the Latissimus 

 and the great skin muscle ; PI. II. By an incision with scissors along 

 the lateral border of the spinal muscles the flap of parietes may be removed 

 as in PL IX. 



7. General View of the Viscera. Compare the specimen with PI. 

 IX ; identify organs and features as far as possible without dislocating 

 them permanently. 



$8. The Omentum (known among the butchers as the "caul") is a membranous 

 "apron" spread more or less completely over the abdominal viscera; sometimes it has 

 been displaced in preparing the specimen, but usually it is recognized without difficulty ; 

 it is traversed by blood-vessels, and in well-nourished animals is commonly streaked with 

 fat ; through the transparent areas between the fat masses may be dimly seen the folds of 

 the intestine. 



a. Make a small slit in the omen turn and blow at the cut edge until 

 the air enters between two layers and inflates the omen turn as a loose bag. 

 In reality each of the two layers thus separated consists of two closely 

 united layers of the peritoneum reflected from the viscera ; for details see 

 the manuals of Human Anatomy and Anatomical Technology, pp. 278, 

 280. 



b. Lift the caudal free border of the omentum and gently draw it 

 sinistro-cephalad, taking care not to displace the viscera ; with the scis- 

 sors cut it off and remove. 



9. The Umbilicus. From the LIVER extends caudad at the meson 

 a fold of peritoneum ; a similar one extends cephalad from the BLADDER ; 

 in young cats, at some point between the ends of these two folds, look for 

 a mesal spot differing more or less in color or texture from the surround- 

 ing parts ; this is the UMBILICUS or navel, the place of attachment of the 

 FUNIS or umbilical cord by which the unborn kitten is connected with the 

 mother. 



a. Before and shortly after birth, could have been traced to it from the liver a vein of 

 which the maternal blood reached the fetus, and from the bladder a pair of arteries carry- 

 ing the fetal blood in the opposite direction ; also a hollow cord, the URACHUS, continuous 

 with the bladder itself. The relations and significance of these parts are presented in the 

 larger works on Anatomy and Physiology and in one of the Lectures. The human umbili- 

 cus is obvious through life from the ectal surface also. 



10. Place the specimen on its back. Look at the prepared skeleton 

 or at the diagram for the XIPHISTERNUM, the caudal extension of the 

 sternum ; it may be felt at the meson, opposite the lobe of the liver 

 marked /, especially if the cut end of the sternum be moved a little ; cut 



