THORACIC CAVITY 



the fact that the lung is ensheathed in visceral pleura. Next, 

 placing his fingers on the inner surface of the parietal pleura 

 behind the costal cartilages, he should carry them upwards 

 towards the head, and he will find that they pass upwards into 

 the root of the neck for a distance of from one to two inches 

 above the level of the anterior part of the first rib, but, on 

 account of the oblique position of the rib, only to the level of 

 its neck posteriorly. The apex of the sac, therefore, lies in 



Sternum 



Discus articularis 

 Clavicle 



Internal mammary 

 artery 



Innominate artery 

 Right innominate 

 vein 



Trachea 



Right vagus 

 Right recurrent 

 nerve 



First thoracic sym- 

 pathetic ganglion 

 Superior intercostal 

 artery 



Third ihoracic 

 vertebra 



Second intercostal 

 nerve 



First rib 



Phrenic nerve 



Right subclavian 



vein 



Right vertebral vein 



Ansa subclavia 

 Right subclavian 51 

 artery ~ 



Eighth cervical - 

 nerve # 



Anterior branch of 

 first thoracic nerve 



Anterior branch of 



second intercostal 



nerve 



Lateral branch of 



second intercostal 



nerve 



Cut lower edge of 

 pleura 



Third rib 



FIG. 5. Structures in relation with the apex of the pleural sac, 

 - seen from below. 



the root of the neck, and by carefully palpating its inner 

 surface, the dissector will be able to distinguish the subclavian 

 artery which passes across its anterior surface below the highest 

 point, and, possibly, he may be able to locate the internal 

 mammary and costo-cervical arteries (O.T. superior inter- 

 costal). The first descends from the subclavian trunk 

 anterior to the apex of the sac, and the second passes first 

 upwards to the apex and then posteriorly above it. After the 

 dissector has examined the position and relations of the 



