6 4 



PR A CTICA L ANA TO. U ) . 



The Hyo-glossus Muscle (Pig. 32). This is the muscle that separates 

 the hypoglossal nerve from the lingual artery. It arises from the body and 

 greater and lesser cornua of the hyoid bone. It passes to the tongue. It is the 

 most deeply located muscle in this region. 



The great branches from the transverse part of the arch of the aorta may be 

 reviewed. In fact, you can not study them and their relations too much. The 

 innominate has been seen dividing into the right subclavian and right common 

 carotid. You may now dissect the branches of the subclavian artery and vein. 



The Subclavian Artery and Vein. The subclavian artery has three stages : 



1. From its beginning to the inner border of the scalenus anticus. 



2. The artery behind the scalenus anticus. (Fig. 36.) 



3. From the scalenus anticus to the lower border of first rib. 



Stylo-glossus 



Hyo-glossus 



Mylo-hyoid 



Anterior belly _ 

 of digastric 



Raplie of mylo- - 

 byoid 



Thyro-hyoid 

 Inferior constrictor 



Anterior belly of 

 omo-hyoid 



Sterno-hyoid 



Sterno-thyroid - 



Scalenus posticus 



mft Posterior belly of 

 omo-hyoid 



I.'K;. 3$. ANTKRIOR ANI> LATKKAI. CKKVICAJ. Mus< i i -. 



Find the scalenus anticus muscle inserted into the scalene tubercle of the first 

 rib. In a groove in front of this tubercle find the ntbclavian vein ; behind the 

 tubercle find the subclavian artery. Behind the artery find the scalcnns incdius 

 muscle inserted into the first rib. Above the artery observe the anterior primary 

 divisions of the fifth, sixth, seventh, and eighth cervical nerves and first dorsal 

 nerve between the scalenus anticus and scalenus medius forming the brachial 

 plexus, 



The subclavian arteries differ on the two sides ; the stages and branches, how- 

 ever, are the same in each as to name. The first stage of the left subclavian is 

 longer than the first stage of the right. 



The right subclavian artery begins behind the right sterno-clavicular articula- 

 tion, at the bifurcation of the innominate artery. The artery lies very deeply. In 



