SURFACE MARKINGS OF THE THORAX 



L30< 





line would cut the sternum in front between the fourth and fifth ribs, the fifth rib 

 in the nipple line, and the ninth rib at the vertebral column." (Treves). 



Diaphragm. -The shape and variations, of the diaphragm as seen by skiag- 

 raphy have already been described (page 407) . 



Surface Lines. For clinical purposes, and for convenience of description, the 

 surface of the thorax has been mapped out by arbitrary lines (Fig. 1220). On the 

 front of the thorax the most important vertical lines are the midsternal, the middle 

 line of the sternum; and the mammary, or, better midclavicular, which runs verti- 

 cally downward from a point midway between the center of the jugular notch and 

 the tip of the acromion. This latter line, if prolonged, is practically continuous 

 with the lateral line on the front of the abdomen. Other vertical lines on the front 

 of the thorax are the lateral sternal along the ternal margin, and the parasternal 

 midway between the lateral sternal and the mammary. 



On either side of the thorax the anterior and posterior axillary lines are drawn 

 vertically from the corresponding axillary folds; the midaxillary line runs down- 

 ward from the apex of the axilla. 



On the posterior surface of the thorax the scapular line is drawn vertically 

 through the inferior angle of the scapula. 





Fio. 1216. Front of thorax, showing surface relations of bones, lungs (purple), pleura (blue), and heart (red 

 outline). P. Pulmonary valve. A. Aortic valve. /J. Bicuspid valve. T. Tricuspid valve. 



Pleurae (Figs. 1216, 1217). The lines of reflection of the pleurae can be indicated 

 on the surface. On the right side the line begins at the sternoclavicular articulation 

 and runs downward and medialward to the midpoint of the junction between the 

 manubrium and body of the sternum. It then follows the midsternal line to the 

 lower end of the body of the sternum or on to the xiphoid process, where it turns 

 lateral ward and downward across the seventh sternocostal articulation. It crosses 

 the eighth costochondral junction in the mammary line, the tenth rib in the mid- 

 axillary line, and is prolonged thence to the spinous process 'of the twelfth thoracic 

 vertebra. 



