212 HANDBOOK OF ANATOMY 



spine of the tenth dorsal vertebra ; this line crosses the eighth 

 rib at the side and the tenth rib at the back. 



The pleura is a little larger than the lungs, especially inf eriorly.. 



The Heart. 



The surface markings of the heart are already given on p. 137- 



The Abdomen. 



The abdomen is most prominent in the region of the umbilicus, 

 which is situated normally below the mid-point between the 

 infrasternal] notch (formed by the seventh costal cartilage and 

 lower border of sternum) and the symphysis pubis, a little below 

 the level of the highest part of the iliac crest and opposite the 

 fourth lumbar vertebra; in obese or pendulous abdomens it 

 may be considerably below this level. 



The anterior abdominal wall is limited above by the infra- 

 sternal notch and costal margin, and below by the fold of the- 

 groin and crest of the pubes. 



In a spare subject the recti and supra-umbilical portion of 

 the linea alba are easily seen; if the outline of the rectus is- 

 obscured by fat, the outer border is indicated by a line drawn 

 from the tip of the ninth costal cartilage down as far as the um- 

 bilicus, then curving forward to the pubic spine. In the angle 

 between the outer border of the rectus and the ninth costal 

 cartilage on the right side lies the gall-bladder. 



The abdomen is arbitrarily divided into nine regions, by two- 

 vertical and two horizontal planes. 



The mid-clavicular lines, continued downwards, cut Poupart's 

 ligament in the mid-point between the anterior superior iliac 

 spine and the pubic symphysis. (Note that this point is not the- 

 mid-point of Poupart's ligament.) In the abdomen these are 

 called the Poupart planes. 



The upper (infracostal) plane is at the level of the lowest part 

 of the tenth costal cartilage, and passes through the third 

 lumbar vertebra. 



The lower (inter tubercular) plane is at the level of the tubercles- 

 of the iliac crests, and passes through the fifth lumbar vertebra, 



,The subdivisions of the upper zone are called the epigastric 



