4 8 



THORAX 



of the same side. In addition, the right innominate vein 

 receives the right lymph duct, or lymph vessels from the 

 head and neck, the upper extremity and the right half of 

 the thorax of the same side; and the left innominate vein 

 receives (a) the left superior intercostal vein, (b) some peri- 

 cardiac and thymic veins, and (<r) the thoracic duct. 



Dissection. After the innominate veins and their tributaries have been 

 studied the left vein may be pushed aside, or, if necessary, it may be cut 

 in order to display the three great branches of the arch of the aorta. 



Left innomi- 

 nate vein 

 Innominate 

 artery 



Phrenic nerve 



Left common 



carotid artery 



Vagus nerve 



Left subclavian 



artery 



Recurrent nerve 



Mediastinal 



pleura 



Thoracic duct 



Cartilage of 



j first rib 

 $1 Internal mam- 



r ( mary vessels 

 Right innomi- 

 nate vein 

 Phrenic nerve 



Trachea 



Vagus 



Oesophagus 



Mediastinal 

 pleura 



FIG. 22. Transverse section through the Superior Mediastinum 

 at level of the third thoracic vertebra. 



Arteria Anonyma. The innominate artery is the largest 

 of the three great branches of the aortic arch. It com- 

 mences, from the upper border of the arch, posterior to the 

 centre of the manubrium, passes upwards and to the right, 

 and terminates, posterior to the upper border of the right sterno- 

 clavicular articulation, by dividing into the right common 

 carotid and the right subclavian arteries. Anterior to it are 

 the manubrium sterni, with the attachments of the sterno- 

 hyoid and thyreoid muscles, the right sterno-clavicular joint, 

 the remains of the thymus gland, and the left innominate vein. 



