THE NINTH NERVE, OR GLOSSO-PHARYNGEAL 6lQ 



portion from a line intermediate between the anterior and posterior nerve 

 roots as far down as the sixth or seventh cervical spinal nerves. 



The combined glosso-pharyngeal-accessory-vagus nucleus appears to con- 

 sist of two parts, viz., one median or common origin, having conspicuous 

 nerve cells of moderate size, and three lateral origins, having but few cells of 

 small size. These are: i, the nucleus ambiguus, which lies on the lateral side 

 of the reticular formation and is the motor origin of the glosso-pharyngeal, 

 the vagus, and the spinal accessory; 2, the fasciculus solitarius, situated in 

 the bulb, ventral and a little lateral to the combined nucleus, is also called the 

 ascending root of the glosso-pharyngeal nerve or the respiratory bundle; and 

 3, the spinal portion, which takes origin from a group of cells lying in the ex- 

 treme lateral margin of the anterior cornu. This is the origin of the spinal 

 accessory; it corresponds to the antero-lateral nucleus of the bulb, and the 

 lateral part of the gray matter of the spinal cord. 



The fibers of the spinal origin of the nerve pass from these cells through 

 the lateral column to the surface of the cord. The fibers from the median 

 part pass in a ventral and lateral direction through the reticular formation, 

 then ventral to or through the gelatinous substance and strand of fibers 

 connected with the fifth nerve, to the surface of the bulb. 



The fibers from the nucleus ambiguus join the combined nerve, chiefly 

 the vagus and the glosso-pharyngeal. 



The bundles of fibers of the fasciculus solitarius start in the lateral gray 

 matter of the cervical cord and higher in the reticular formation of the bulb, 

 run longitudinally forward, to pass into the roots of the ninth nerve. It is 

 composed of sensory fibers, chiefly of the glosso-pharyngeal, and of the 

 pars intermedia of the facial. 



The glosso-pharyngeal nerve gives filaments through its tympanic branch 

 (Jacobson's nerve), to the fenestra ovalis and fenestra rotunda, and the Eu- 

 stachian tube; also to the carotid plexus, and through the petrosal nerve, to 

 the spheno-palatine ganglion. After communicating with the vagus and, 

 soon after it leaves the cranium, with the sympathetic, with the digastric 

 branch of the facial, and the accessory nerve, the glosso-pharyngeal divides 

 into the two principal divisions indicated by its name. These divisions 

 supply the mucous membrane of the posterior and lateral walls of the 

 upper part of the pharynx, the Eustachian tube, the arches of the palate, 

 the tonsils and their mucous membrane, and the tongue as far forward 

 as the foramen cecum in the middle line, and to near the tip at the sides and 

 inferior part. 



Functions. The glosso-pharyngeal nerve contains some motor fibers, 

 together with fibers of common sensation and the sense of taste. 



Motor fibers are distributed to the palato-pharyngeus, the stylo-phar- 

 yngeus, palato-glossus, and constrictors of the pharynx. 



Sensory fibers of touch and of common sensation are distributed to the 



