THE THORAX. 107 



found in works specially devoted to the subject, it is 

 proposed merely to point out the chief anatomical bear- 

 ings of the contained viscera. 



The Lungs. Presuming the body to be normal, their 

 position with regard to the thoracic walls is as follows : 

 The apices lie beneath the scalenus anticus muscle and 

 the subclavian artery, separated by the oesophagus, tra- 

 chea, and anterior portion of the bodies of the first and 

 second dorsal vertebrae. The bases of each are separated 

 from the abdominal viscera by the diaphragm, that of 

 the right being considerably hollowed out by the bulg- 

 ing upwards of the liver, as far up in the thorax as the 

 fifth rib ; that of the left is hollowed out to a less degree 

 by the projection of the stomach, spleen, and left lobe of 

 liver. 



The inner margin of the right lung passes vertically 

 down the middle of the sternum, with a slight inclina- 

 tion to the same side, as far as the sterno-xiphoid articu- 

 lation. 



The inner margin of the left lung lies parallel with that 

 of the right, about as far as to the fourth costal carti- 

 lage, where it passes outwards along this cartilage for a 

 short distance, and then descends obliquely downwards 

 and backwards, a little internal to the nipple, nearly as 

 far as the seventh rib. 



The Heart. The heart lies obliquely, and during ex- 

 piration is nearly horizontal, its base being to the right 

 and apex to the left side. The base corresponds to the 

 interval between the fifth and eighth dorsal vertebrae, 

 and its apex to a little below the left fifth rib, to the 

 left of its junction with its cartilage, while the impulse 

 is to be felt in the interspace between the cartilages of 

 the fifth and sixth ribs, internal to the nipple. Its 



