128 



THE HUMAN BODY 



branches arise and unite to make the phrenic nerve (4', Fig. 63) 

 which runs down through the chest and ends in the diaphragm. 



The ventral primary branches of the thoracic nerves, except 

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



IU 



FIG. 63. The cervical and brachial plexuses of the left side of the Body. 



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 ventral primary branches of the four anterior lumbar 

 nerves are united by branches to form the lumbar plexus. It sup- 



