PHYSIOLOGY FOR BEGINNERS 



CHAP. 



like muscles of the flanks and of the anterior wall, and below 

 is the pelvis or girdle of bone formed by the two hip bones, to 

 which the thigh bones are attached. Of the sheet-like muscles 

 there are three placed on one another, and all united together 

 into a white band of tendon running down the middle of the 

 anterior wall. On each side of this white band there is a 

 narrow band-like muscle running parallel with it. Thus the 

 front and side walls of the abdomen are made up by four 



d.m. 



Intest 



_J* 



FIG. 2. Diagram to show how the wall of the abdomen is made up, and how 

 the mesentery supports the intestine. 



The body is supposed to be cut across, and the intestine is represented as the 

 section of a straight tube. In reality the space between the intestine and the 

 body wall is filled by the coils of the intestine and by other organs. 



Vert, vertebra; d.>n, muscles of back ; sk, skin; /', >;/-, *, the three muscle 

 layers \pcrit, peritoneum ; ines, mesentery ; infest, intestine ; 6.7', blood-vessels. 



distinct muscles on each side of the middle line, these being 

 covered by a layer of fat, and then by the skin. The inner side of 

 the layer of muscles is covered by a thin transparent membrane, 

 called the peritoneum. This membrane covers also the 

 muscles and spinal column at the back, and the under surface 

 of the diaphragm above, as well as the pelvic bones and muscles 

 on the inner side of the pelvic bones below, forming, in fact, a 

 continuous and closed lining for the abdominal cavity. From 

 the vertebral column the peritoneum passes out into the cavity 



