ANATOMY OF THE NERVOUS SYSTEM. 



165 



From the fourth and fifth cervical nerves on each side, small 

 branches arise and unite to make the phrenic nerve (4', Fig. 

 72) which runs down through the chest and ends in the 

 diaphragm. 



The anterior primary branches of the dorsal nerves, except 

 part of the first which enters the brachial plexus, form no 



FIG. 72. The cervical and brachial plexuses of the left side of the Body. 



plexus, but each runs along the posterior border of a rib and 

 supplies branches to the chest- walls, and the lower ones to 

 those of the abdomen also. 



The anterior primary branches of the four anterior lumbar 

 nerves are united by branches to form the lumbar plexus. 



