THE GLOSSO-PALATINE NERVE 947 



glosso-pharyngeal nerve and suggest that it may be considered an aberrant portion 

 of that nerve. 



The sensory portion is much greater than the motor. Its fibres arise from cells 

 situated in the geniculate ganglion which thus corresponds to a spinal ganglion. 

 The central processes from these cells pass medialward in the facial canal (aqueduct 

 of Fallopius) enclosed in the sheath of the facial nerve, which they leave in passing 

 through the internal auditory meatus, to turn slightly downward in the posterior 

 fossa of the cranium and enter the medulla at the inferior border of the pons, be- 

 tween the attachments of the facial and vestibular nerves. They course through 

 the reticular formation of the medulla, medianward and dorsalward to terminate 

 about cells which comprise a superior extension of the nucleus of termination 

 of the glosso-pharyngeal nerve (nucleus of ala cmerea). The peripheral processes 

 from the geniculate ganglion are distributed chiefly to the epithelium covering the 

 soft palate, portions of the glosso-palatine arches, and the anterior two thirds of 

 the tongue. 



The geniculate ganglion is so named from the fact that it is embedded upon the 

 anterior border of the external genu {geniculum, great bend) of the facial nerve, 

 behind the hiatus Fallopii. It is somewhat triangular in form. From its supero- 

 medial angle leave the central processes of its cells, the root of the nerve; from its 

 infero-lateral angle leave the fibres which later leave the sheath of the facial as the 

 chorda tympani, and its anterior angle is connected with the great superficial 

 petrosal nerve (figs. 738 and 741). The geniculate ganglion contains a rel- 

 atively large number of cell-bodies of sympathetic neurones many of whose 

 processes run in this latter nerve, a relation mentioned below with the gangliated 

 cephalic plexus. 



The motor portion of the glosso-palatine consists for the most part of visceral 

 efferent fibres, chiefly secretory. These arise in the medulla oblongata from a 

 small group of cells scattered in the reticular formation dorso-medial to the 

 nucleus of the facial and in line with the dorsal efferent nucleus of the vagus 

 below. It is called the salivatory nucleus. The fibres course ventralward and 

 lateralward to their exit, mingle with the entering sensorj^ fibres of the glosso- 

 palatine in the sheath of the facial and, through the branches of the glosso- 

 palatine, pass to terminate in sympathetic ganglia of the head, large and small. 

 These ganglia send axones which terminate in the smooth muscle of vessels and 

 about the cells of the glands of the lingual and palatine mucous membrane and of 

 the salivary glands proper. Some of the motor fibres of the nerve terminate in 

 contact with the sympathetic cells remaining in the geniculate ganglion and which 

 give rise to sympathetic fibres issuing from it. Most of the motor fibres pass 

 into the great superficial petrosal nerve and the chorda tympani to terminate in 

 (chiefly) or pass through the spheno-palatine and submaxillary ganglia re- 

 spectively. Some may pass by the geniculo-tj'mpanic branch and tympanic 

 plexus to end in the otic ganglion. Many no doubt end in the smaller ganglia 

 involved in the various sympathetic plexuses. It is suggested that the motor 

 part carries secretory impulses destined chiefly for the sub-maxillary and sublin- 

 gual glands. A small gangliated plexus on the capsule of the medial side of the 

 parotid gland has been frequentty dissected and found to communicate freely with 

 twigs from the facial nerve and twigs concerned with the trigeminus. It is 

 possible that some glosso-palatine visceral motor fibres terminate in these ganglia 

 for secretory impulses to the parotid gland as well. 



Central connections. — The nucleus of termination of the glosso-palatine nerve (superior 

 extension of the nucleus of termination of the sensory portion of the glosso-pharyngeal) is 

 associated with the somaesthetic area of the cerebral cortex of the opposite and same sides by 

 way of the medial lemniscus, and with the salivatory nucleus and motor nuclei of other cranial 

 Berves by way of the reticular formation and medial longitudinal fasciculus. The nucleus of 

 origin of the motor portion (salivatory nucleus) may be associated not only with the nucleus 

 of termination of the sensory part, but with the nuclei of termination of other cranial nerves, 

 and perhaps with the motor area of the cortex of the opposite side by way of the pyramidal 

 fasciculi. 



Branches and communications. — ^Aside from its two or three small collateral 

 twigs of communication, the fibres of the glosso-palatine course in two main 

 branches or nerves: (1) the great superficial petrosal nerve, continued tlirough 

 the Vidian nerve, and extended through and beyond the spheno-palatine ganglion 

 as the palatine portion of the glosso-palatine (palatine nerve) ; (2) the chorda tym- 



