DISSECTION OF THE VASCULAR SYSTEM. 57 



5. The Brachio-cephalic {innominate) Veins- The 

 two large veins which unite to form the prae-cava. 

 Each after a short course divides into the sub-clavian 

 and external jugular. 



6. The Sub-clavian Vein brings back blood from 

 the arm, shoulder, etc. Beyond the point where it 

 joins the external jugular it receives the siib.-scapular 

 vein. Followed into the arm it will be found to re- 

 ceive a number of muscular branches. 



7. The External Jugular passes toward the head, 

 lying just below the skin in its course through the 

 neck. Near the level of the larynx the jugular 

 divides into two branches, t\\Q facial "mx^ the temporal, 

 brincringf back blood from the head. The sub-maxil- 

 lary gland lies between these two veins and sends a 

 small vein to each of them. The facial veins of the 

 two sides are united by a wide cross-branch — the 

 tra7isvcrse vein. 



8. The Internal Jugular. Near the junction of the 

 external jugular and s.ub-clavian the former receives 

 the internal jugular, which has a deeper course along 

 the side of the trachea. It brings back blood from 

 the brain. 



E. THE ARTERIES OF THE ANTERIOR POR- 

 TION OF THE BODY. 



1. The Arch of the Aorta. Clean the fat, etc., from 

 the arch. The following branches are given off from it : 



2. The Brachio-cephalic {innominate) Artery, given 

 off nearest to the heart. 



3. The Left Sub-clavian Artery, given off separately, 

 and distributed to the left arm, shoulder, etc. 



4. The Common Carotid Arteries. Dissect out the 

 brachio-cephalic trunk. The two common carotids 



