59G 



DISSECTION OF THE NECK. 



branches. Large lymphatic vessels from the left side of the head and neck,j 



and from the left upper liml>, open into the upper part of the duct, 

 and sometimes separately into the veins ( 10 ). 



The ANTERIOR PRIMARY BRANCHES OF THE CERVICAL NERVES 



spring from the common trunks in the intervertebral foramina, and 

 appear on the side of the neck between the intertransverse muscles. 

 position and These nerves are eight in number, and are equally divided between 

 the cervical and brachial plexuses ; the upper four being combined 

 in the former, and the remaining nerves in the latter plexus. 

 Close to their origin they are joined by offsets of communication 

 from the sympathetic cord. 



To this general statement some addition is needed for the first 

 two nerves, the peculiarities of which will be noticed later. 



Cervical 



number. 



First two 



FIG. 215. DIAGRAM OF THE ENDING OF THE RIGHT LYMPHATIC DUCT ANI> 

 THE THORACIC DUCT IN THE VEINS. 



1. Upper vena cava. 



2. Right, and 3, left innominate 

 vein. 



4. Left, and 5, right internal 

 jugular. 



6. Left, and 7, right subclavian 



8. Thoracic duct. 



9. A lymphatic trunk joining the 

 right lymphatic duct, as this is about 

 to end in the subclavian vein. 



10. A lymphatic trunk opening 

 separately into the left subclavian 



Brachial 

 plexus, 



formed by 

 five nerves. 



Disposition 

 of nerves in 

 the plexus. 



BRACHIAL PLEXUS (fig. 216). The lower four cervical nerves 

 and the larger part of the first dorsal are blended in this plexus ; 

 and a fasciculus is added to them from the lowest nerve entering 

 the cervical plexus. Thus formed, the plexus reaches from the 

 neck to the axilla, where it ends in nerves for the upper limb. 

 Only the part of it above the clavicle can now be seen. In the 

 neck the nerves lie at first between the scaleni muscles, opposite 

 the four lower cervical vertebrae, and afterwards in the posterior 

 triangular space. The arrangement of the nerves in the plexus is 

 as follows : 



The fifth and sixth nerves unite near the vertebra), forming an 

 upper primary trunk ; the seventh remains distinct and constitutes 



