THORACIC CAVITY 



37 



diaphragm ascends higher than the left, the basal concavity 

 of the right lung is deeper than that of the left lung. The 

 lateral and posterior parts of the basal margin of the lung 

 are thin and sharp and extend downwards into the phrenico- 

 costal sinus of the pleura, which intervenes between the 

 diaphragm and the wall of the thorax. This margin reaches a 

 much lower position posteriorly and laterally than anteriorly, 

 but in all situations it falls considerably short of the bottom of 

 the sinus. The mediastinal part of the basal margin, which 

 lies along the lower border of the pericardium, is more 

 rounded. 



The diaphragm separates the base of the right lung from 



Right vagus nerve 



Righ 

 subclavian artery 



Right 

 innominate vein 



Innominate^ 

 artery 



Trachea 



Oesophagus Left subclavian artery 



Sulcus subclavius 



Left 



vagus nerve 



FIG. 15. Cervical Domes of the Pleural Sacs, and parts in relation to them. 



the upper surface of the right lobe of the liver, and the base 

 of the left lung from the left lobe of the liver, the stomach, 

 the spleen, and, in some cases, from the left extremity of the 

 transverse colon. 



The costal surface of the lung is very extensive and convex. 

 It lies in relation with the costal pleura, which separates it 

 from the ribs and intercostal muscles, the transversus thoracis 

 and the sternum, and it bears the impressions of the costal 

 arches. 



The medial surface is separable into an anterioror^^VzsftVfO/ 

 portion and a posterior or vertebral portion. The vertebral 

 portion lies against the sides of the bodies of the vertebrae. 

 The mediastinal part is applied against the mediastinal 

 partition and presents markings which are the exact counter- 

 parts of the inequalities of the corresponding lateral surface 

 n36 



