374 NEUROLOGY, OR ANATOMY OF NERVOUS SYSTEM 



The external runs under the extensor brevis digitorum, and 

 supplies it as well as the neighboring joints. 



The internal accompanies the dorsal artery of the foot to 

 the first interosseous space, and supplies the skin of the great 

 and second toes, joining a branch of the musculocutaneous. 

 Both these nerves send interosseous branches to the metatarso- 

 phalangeal joints. 



THE SYMPATHETIC NERVOUS SYSTEM 



The sympathetic nervous system consists of a series of ganglia, 

 cords, and plexuses, with their communicating and distrib- 

 uting nerve fibers. Its nerves supply all the viscera and the 

 coats of the bloodvessels. 



There are two principal gangliated cords, lying one on each 

 side of the spine from the base of the skull to the coccyx. They 

 consist of a series of ganglia connected by short single or 

 double cords. The number of the ganglia corresponds in general 

 to that of the vertebrae in the several regions, except in the 

 neck, where there are but three. 



Below, these cords end on the front of the coccyx by a loop 

 on which is the ganglion impar, and above they are connected 

 with the carotid plexus in the carotid canal. 



The ganglia are connected with the spinal nerves by gray and 

 white fibers, the former passing from the ganglia to the spinal 

 nerves, and the latter rice rrrsd. The ganglia are also connected 

 together by gray and white fibers, the latter being continuous 

 with the fibers of the spinal nerves prolonged to the ganglia, 



There are three great plexuses, consisting of nerves and 

 ganglia, They are single and lie in front of the spine in the 

 thoracic, abdominal, and pelvic regions, and each is named, 

 from above downward, the cardiac, epigastric, and hypogastric 

 plexus. 



THE SYMPATHETIC NERVES OF THE NECK 



The cervical part consists of three ganglia, named superior, 

 middle, and inferior, on each side. 

 The superior ganglion, opposite the second and third cervical 



