576 



DISSECTION OF THE NECK. 



clavian artery. It is bounded in front by the sterno-mastoid, above 

 by the posterior belly of the omo-hyoid, _and below by the clavicle. 



FIG. 210. PART OF THE POSTERIOR TRIANGLE OF THE NECK is HERE DIS- 

 PLAYED, BUT THE STUDENT SHOULD CARRY THE DISSECTION AS HIGH AS 

 THE HEAD, so AS TO LAY BARE THE WHOLE OF THAT SPACE. 



7. Third part of subclavian 

 artery. 



8. External jugular vein joining 

 the subclavian below. 



. Brachial plexus. 



1. Sterno-mastoid. 



2. Trapezius. 



3. Posterior belly of omo-hyoid. 



4. Anterior scalenus, with the 

 phrenic nerve on it, exposed by the 

 shrinking of the sterno-mastoid. 



5. Middle scalenus. 



6. Levator anguli scapulse. 



10. Spinal accessory nerve. 

 (Blandin's Surgical Anatomy. ) 



Extent of 

 the space. 



Trunks of 

 vessels and 

 nerves. 



This space measures commonly about two inches from before 

 backwards, and about one inch from above downwards at its base. 



Crossing the area of this space, rather above the level of the 

 clavicle, is the trunk of the subclavian artery (fig. 210, ; ) which 



