286 ANATOMY IN A NUTSHELL. 



pneumogastric nerve, (4) Left phrenic nerve, (5) Superficial cardiac nerves 

 (6) Left superior intercostal vein. 



Behind. — (1) Trachea, (2) Deep cardiac plexus, (3) Oesophagus, (4) 

 Thoracic duct. (5) Left recurrent laryngeal nerve. 



The Relations of the Thoracic Aorta are: (Plate CXXVIII.) 



I\ Front. — (1) Root of left lung, (2) Pericardium, (3) Oesophagus, (4) 

 ] Haphragm. 



Behind. — (1) Vertebral column, (2) Superior and inferior azygos minor 

 veins. 



Right Side. — (1) Oesophagus (above), (2) Vena azygos major, (3) Thorac- 

 ic dud. 



Left Side. — (1) Pleura, (2) Left lung, (3) Oesophagus (below.) 



The ascending aorta has the right coronary and the left coronary artery 

 which have been described with the heart. The branches of the arch of the 

 aorta arc (1) innominate, (2) left common carotid, (3) left subclavian. The 

 branches of the thoracic aorta are (1) pericardiac, (2) bronchial, (3) oesopha- 

 geal. (4) posterior mediastinal, (o) intercostal. 





LESSON LXXX. 



The innominate artery often called brachio-cephalic has its beginning 

 opposite the fourth dorsal vertebra just in front of the left common carotid. 

 It is the largest of the branches of the arch of the aorta. At the upper border 

 of the right sterno-clavicular articulation it divides into the right common 

 carotid and the right subclavian. It is from an inch and a half to two inches 

 long and has no branches as a rule, but the thyroidea ima may arise from it. 



The Relations of the innominate artery are as follows; 



1\ Front. — (1) Sternum. (2) Sterno-hyoid and (3) Sterno-thyroid muscles, 

 (4) Remains of the thymus gland. (5) Left innominate vein, (6) Right inferior 

 thyroid vein, (7) Inferior cervical cardiac branch from right pneumogastric 

 nerve. 



Behind. — Trachea. 



Right Side. — (1) Right innominate vein, (2) Right pneumogastric nerve. 



Pleura. 



Left Side. — (1) Remains of thymus gland. (2) Left carotid artery, (3) 

 Lef1 inferior thyroid vein, (4) Trachea. 



The rijrht common carotid artery (Plates CXVI-CXVII) arises from the 

 innominate at the upper border of the right sterno-clavicular articulation. It 

 passes obliquely upward and divides into the external carotid and internal 

 carotid at the upper border of the thyroid cartilage opposite the fourth cervical 

 vertebra. 



The left common carotid artery comes from the highest part of the arch of 

 the aorta and passes upward behind the left slerno-calvicular articulation to 

 divide into the external carotid and internal carotid at the upper border of the 

 thyroid cartilage opposite the fourth cervical vertebra. These arteries are 

 enclosed in a common sheath of cervical fascia with the internal jugular vein 



