128 Anatomy Applied to Medicine and Surgery. 



the original direction, until it reaches the junction of the 

 sixth costal cartilage with the sternum, where it changes 

 its direction, and becomes the inferior border. This passes 

 outwards, and crosses the lower border of the sixth 

 rib in the mammary line, the eighth rib in the midaxillary 

 line, and the tenth in the scapular line, and then termi- 

 nates behind at the level of the tenth dorsal spine. On 

 the left side, after the line for the anterior margin leaves 

 the sternum at the level of the fourth cartilage, it passes 

 downwards and outwards, along the lower border of this 

 cartilage for about one and a half inches. It then drops 

 downwards, for .about half an inch, to the upper border of 

 the fifth cartilage, then inwards, towards the sternum, for 

 a distance of half an inch along the fifth cartilage, and 

 then, downwards, half an inch to the sixth, after which it 

 continues outwards in a manner similar to, though at a 

 slightly lower level than, the line already described for 

 the lower border of the right lung. ( Fig. 6. ) The posterior 

 border of the lung corresponds to a line starting at a point 

 opposite the seventh cervical spine, and, at a distance of 

 about one inch from the midspinal line and then passing 

 downwards, to terminate about the level of the tenth dorsal 

 spine. The greater fissure of the right lung may be re- 

 presented by a line drawn from the third dorsal spine, 

 downwards and forwards, to where the sixth rib is cross- 

 ed by the inferior border of the lung, i.e., to the point 

 where the mammary line meets the sixth rib. Another 

 landmark for this fissure is the situation of the posterior 

 border of the scapula, when the arm is raised so that the 

 hand rests on the back of the head. ( Fig. 8. ) The lesser fis- 

 sure of the right lung agrees, fairly well, with a line drawn 

 from the point where the greater fissure crosses the midax- 

 illary line, to the junction of the fourth costal cartilage, on 

 the right side, with the sternum. The fissure of the left lung 



