94 ANATOMY AND PHYSIOLOGY. 



from being distributed principally to the lungs and stomach. These 

 are large nerves that run behind the carotid arteries in the neck. 

 Although they have been very frequently experimented on, their 

 functions are still a subject of dispute. There seems no doubt that 

 they give motor branches to the top of the windpipe, the pharynx, 

 the oesophagus, and probable also to the lungs, and they also seem 

 to furnish us with some of the sensations from the lungs. When 

 the pneumogastric nerves are cut below the branches to the wind- 

 pipe, the effect is, as formerly mentioned, generally, though not 

 uniformly, to suspend the process of digestion, the food remaining 

 in the stomach nearly unaltered. It was to these nerves that Dr. 

 Philip, under these circumstances, applied galvanism, and found 

 that the power of digestion was then restored. 



No. 8" (Fig. 32) is called the spinal accessory, and is considered 

 to be a motor nerve. It is distributed to the muscles of the neck 

 and shoulder. This is called by some anatomists the third branch 

 of the eighth pair, the glossopharyngeal and pneumogastric being 

 considered its first and second branches. The next or hypoglossal 

 nerves, in this way, come to be called the ninth pair. 



No. 9 (Figs. 32 and 33) is a nerve of motion, called the hypo- 

 glossal from going to the muscles, and consequently producing the 

 movements of the tongue. 



No. 10 (Figs. 32 and 33) is called the suboccipital nerve, from 

 coming out immediately below the occiput or back of the head. It 

 goes to the back of the neck, &c., and belongs to the strictly regu- 

 lar nerves, or those which have both sensiferous and motor roots. 

 All the spinal nerves below this, as seen in Figs. 32 and 33, also 

 have sensitive and motor roots. They become interwoven in their 

 course, forming, in different parts, what is called a plexus. The 

 principal of these are, 1st, the cervical plexus (Fig. 33, ra), which 

 gives off, among others, two important nerves, one of which goes 

 to the diaphragm, and is called the phrenic or internal respiratory 

 nerve, and the other, from being also concerned in respiration, is 

 called by Sir Charles Bell the external respiratory nerve, g, Fig. 

 33, is called the brachial plexus, from supplying nerves to the arm. 

 Below this are the dorsal nerves (/), the lumbar nerves (TI), and the 

 sacral plexus (&), which last furnishes the large nerves that go to 

 the lower extremity. 



It is evident that the influence of the will is confmetf to the 

 nerves, and does not extend to the arteries or other solid parts of 

 the body. 



