FUNCTIONS OF THE CEPHALIC NERVES. 181 



[Fig. 41. 



The course and distribution of the Hypo-Glossal or Ninth pair of nerves; the deep-seated nerves of the 

 neck are also seen; 1, the hypo-glossal nerve ; 2, branches communicating with the gustatory nerve; 3, a 

 branch to the origin of the hyoid muscles ; 4, the descendens noni nerve; 5, the loop formed with the branch 

 from the cervical nerves; 6, muscular branches to the depressor muscles of the larynx; 7, a filament from 

 the second cervical nerve, and 8, a filament from the third cervical, uniting to form the communicating 

 branch with the loop from the descendens noni; 9, the auricular nerve; 10, the inferior dental nerve; 11, its 

 mylo-hyoideau branch; 12, the gustatory nerve; 13, the chorda-tympani passing to the gustatory nerve ; 

 14, the chorda-tympani leaving the gustatory nerve to join the sub-maxillary ganglion ; 15, the sub-maxil- 

 lary ganglion ; 16, filaments of communication with the lingual nerve; 17, the glosso-pharyngeal nerve; 

 18, the pneumogastric or par vagum nerve; 19, the three upper cervical nerves; 20, the four inferior cer- 

 vical nerves ; 21, the first dorsal nerve ; 22, 23, the.brachial plexus ; 24 ; 25, the phrenic nerve ; 26, the carotid 

 artery ; 27, the internal jugular vein.] 



243. The character of the Cephalic nerves, as distinguished from the 

 Spinal, is a point of much interest, when considered in relation to Compara- 

 tive Anatomy, and to Embryology. It appears, from what has heen already 

 stated, that the Par Vagum, Spinal Accessory, Glosso-pharyngeal, and Hypo- 

 glossal nerves, may be considered nearly in the light of ordinary Spinal 

 nerves. They all take their origin exclusively in the Medulla Oblongata ; 

 and the want of correspondence in position, between their roots and those of 

 the Spinal nerves, is readi]y accounted for,^by the alteration in the direction 

 of the columns of the Spinal Cord, which, as long since pointed out by 

 Rosenthal, and lately stated prominently by Dr. Reid, not only decussate 

 laterally, but, as it were, from behind forwards ( 171). The Hypoglossal, as 

 just stated, not unfrequently possesses a sensory in addition to its motor root. 

 The Glosso-pharyngeal, which is principally an afferent nerve, is stated by 

 Arnold and others to have a small motor root ; at any rate, the motor fibres 

 which belong to it are to be found in the Par Vagum. That the Par Vagum 

 and a portion of the Spinal Accessory together make up a spinal nerve, has 

 been already stated as probable. Leaving these nerves out of the question, 



author by Dr. W. Budd, in which the hypoglossal nerve was completely divided on one 

 side; and yet the tip of the tongue, when the patient was desired to put it out, was some- 

 times directed from and sometimes towards the palsied side ; showing that the muscles 

 of either half are sufficient to give any required direction to the whole. 

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