THE GLOSSO-PHARYXGEAL NERVE. 



555 



front of the others, this nerve is contained in a groove, or in a canal in 

 the lower border of the petrous portion of the temporal bone, and 

 presents, successively, two ganglionic enlargements, — the jugular gano-- 

 lion, and the petrous ganglion. 



After leaving the skull, the glosso-pharyngeal nerve appears between 

 the internal carotid artery and the jugular vein, and is directed down- 

 wards over the carotid artery and beneath the styloid process and the 

 muscles connected with it, to the lower border of the stylo-pharyngeus 

 muscle. Here, changing its direction, the nerve curves'inwards to the 

 tongue, on the stylo-pharyngeus and the middle constrictor muscle of 

 the pharynx, above the upper laryngeal nerve ; and, passing beneath 

 the hyo-glossus muscle, ends in branches for the pharynx, the tonsil, 

 and the tongue. 



The jugular ganglion, the smaller of the two ganglia of the glosso- 

 pharyngeal nerve, is situated at the upper part of the osseous groove in 

 which the nerve is laid during its passage through the jugular foramen. 

 Its length is from half a line to a Ime, and the breadth from half to 

 three-fourths of a line. It is placed on the outer side of the trunk of 

 the nerve, and involves only a part of the fibres,— a small fascicidus 

 passing over the ganglion, and joining the nerve below it. 



Fix. G46. 



Fig. 346. — Sketch of the Tympanic 

 Branch of the Glosso-Phartn- 



OEAL JS'eRVE, and ITS CONNECTIONS 



(from Breschet). 



A, squamous part of the left tem- 

 poi'al bone ; B, petrous part : C, in- 

 ferior maxillary nerve ; D, internal 

 carotid artery ; a, tensor tympani 

 muscle ; 1, carotid plexus ; 12, otic 

 ganglion ; 3, glosso-pharyngeal nerve ; 

 4, tjTnpanic nerve ; 5, twigs to the 

 carotid plexus ; 6, twig to fenestra 

 rotunda ; 7, twig to fenestra ovalis ; 

 8, junction with the large superficial 

 petrosal nerve ; 9, small superficial 

 petrosal; 10, twig to the tensor tym- 

 pani muscle; 11, facial nerve; 12, 

 chorda tympani ; 13, petrous ganglion 

 of the glosso-pharyngeal ; 14, twig to 

 the membrane of the Eustachian 

 tube. 



The petrous ganglion is 

 contained in a hollow in the 

 lower border of the petrous 

 part of the temporal bone 

 (receptaculum ganglioli petrosi), and measures about three lines in 

 length. This ganglion includes all the filaments of the nerve, and 

 resembles the gangliform enlargement of the facial nerve. From it 

 arise the small branches by which the glosso-pharyngeal is connected 

 with other nerves at the base of the skull ; these are the tympanic 

 nerve, and the branches which join the pneumo-gastric and sympathetic. 

 Connecting branches, and tympanic branch. — From the petrous ganglion 

 spring three small connecting filaments. One passes to the auricular branch of 

 the pneumo-gastric, one to the upper ganglion of the sympathetic or vice vcrna. 



