718 



THE NEKVOUS SYSTEM. 



lumbar nerve in the psoas muscle. It may communicate also with the ilio-hypogastric nerve, as 

 they lie together in the abdominal wall. 



Inter-communications of the Thoracic Nerves. It has been noted already that the belts or 

 areas of skin supplied by the branches of the thoracic nerves are also innervated by adjacent 

 nerves on either side which invade the area supplied by a given nerve. Communications also 

 take place between the branches of the nerves supplying the intercostal muscles, whereby the' 

 muscles of a given space derive their innervation from more than one intercostal nerve. 



SYMPATHETIC 



LATERAL CUTANEOUS 

 NEKVE OF THE THI 



WHITE RAMUS 

 S3 



WHITE RAMUS 

 S4 



SCIATIC 



FIG. 624. NERVES OF THE LUMBO-SACRAL PLEXUS. 



PLEXUS LUMBOSACRALIS. 



The lumbo-sacral plexus is formed by the union of the anterior rami of th 

 remaining spinal nerves five lumbar, five sacral, and one coccygeal. Frequently 



