UPPER EXTREMITY AND THORAX, ANTERIOR. 255 



THE UPPER EXTREMITY AND THORAX, 

 Anterior. 



THE LANDMARKS. 



In the median line there is the suprasternal or interclavi- 

 cular notch between the large rounded ends of the clavicles. 

 This notch is always easily felt even in very fleshy people, 

 and is therefore a very valuable reference point. The notch 

 is directly in front of the disk between the second and third 

 dorsal vertebrae, and two and one-half inches from it. 

 About two inches below the notch is a prominent transverse 

 ridge marking the articulation of the first and second por- 

 tions of the sternum. This ridge is also a guide to the 

 second ribs and cartilages which join the sternum at this 

 place. At the lower end of the sternum is the ensiform 

 appendix, which can be felt on pressure, also the transverse 

 ledge or jog which marks where the appendix unites with 

 the second piece of the sternum. This place receives the 

 cartilages of the seventh ribs, and is therefore a guide to 

 them. The tip of the ensiform is in front of the body of 

 the ninth dorsal vertebra. 



For the remarks concerning the lower margin of the 

 thorax, see page 432. The nipples are usually given as 

 points from which to reckon distances and relations. Their 

 position is so variable, especially in the female, as to scarcely 

 deserve mention ; however, it will be given here. As a 

 rule, in both sexes they are found over the fourth interspace, 

 in males about three and one-half inches, and in females 

 four inches, from the median line, or about one inch ex- 

 ternal to the junction of the ribs and cartilages. 



The clavicles are distinct, and extend outward and slightly 

 upward from the lateral margin or angle of the manubrium 



