GLOSSO-PIIARYNGEAL,) and one or more be tween it and the spinal accessory.§ From the lower and external part of this ganglion a small nerve arises, (rainus auricularis nervi vogi,) which is seen joined by another small branch from the lower part of the ganglion petrosum of the glosso-pharyngeal.* The ramus auricularis proceeds outwards and a little back wards anterior to the jugular vein, and lies in a groove in that portion of the petrous portion of the temporal bone which assists in forming the fossa jugularis, perforates the osseous partition between the fossa jugularis and the aqueduct of Fallopius, and enters the internal side of the latter about one or two lines above its lower termination in the stylo-mastoid foramen. It now divides itself into two branches, a small ascending twig which joins the panic) dura nerve, and a larger portion which enters a canal on the external side of the aqueduct of Fallo pins, proceeding outwards and a little back wards through that portion of the spongy por tion of the temporal bone which forms the lower wall of the external meatus. The larger branch subdivides into two other branches as it lies in this canal. One of these emerges upon the external surface of the cranium through a small opening between the mastoid process and the posterior margin of the meatus auditorius, and divides into two or three twigs, which pass through openings in the cartilage of the pavillon of the external ear, and are ultimately distri buted upon the tegumentary covering of the internal surface of the concha and meatus audi torius externus. The other branch of the nerve passes through the mastoid process and joins itself to the auricular branch of the portio dura, and along with it is distributed upon the pos terior surface of the pavilion of the external. earl- The trunk of the spinal accessory is closely connected to the posterior surface of the superior ganglion of the vagus by cellular 4ssue, and immediately below the lower end of the ganglion it throws a considerable branch into the vagus. The exact place and manner in which these auxiliary fibres from the accessory join the vagus differ in different individuals, and sometimes in the two sides of the same individual, but most generally the spinal acces sory divides itself at the lower part of the fora men lacerum into two branches, the internal and external branches of the spinal accessory. The internal branch runs immediately into the anterior and outer part of the vagus, and while one portion of its fibres goes to form a part of the suierior_pharyngeal branch of the vagus, the other portion joins itself to the trunk of the vagus, and accompanies it clown the neck.
Sometimes the fibres of the internal branch of the accessory are arranged in two bundles, and in such cases the one generally joins itself to the vag,us a little below the other. The exter nal branch of the accessory proceeds downwards and outwards, perforates the upper part of the sterno-cleido-mastoid muscle, and ultimately terminates in the travezius muscle.
The superior ganglion of the vagus was known to Ehrenritter.* It appears also to have been well known to Wutzer, for it is both mentioned and figured by him in his monograph De Cor poris Humani Gangliorum Fab. et Usu, 1818. Wutzer has in fig. vii. certainly represented it as being placed somewhat inferior to the gan glion petrosum of the glosso-pharyngeal, instead of being rather above it : yet as lie terms it ganglion primum n. v. and fio-ures the ganglion .
secundum in its proper position, there can be no doubt that lie was well aware of its exist ence. It has been supposed by some that Lobsteint had also pointed out the existence of this ganglion, while others maintain that his description is not sufficiently explicit to enable us to decide whether it refers to the upper or lower ganglion of the vagus. It appears, how ever, much more probable that it is the superior ganglion, for after mentioning that the vagys presents a reddish appearance, similar to a ganglion, (rubella parum quasi ganglion men tiretur,) he describes the superior pharyngeal branch of this nerve as arising below it. Miillert has attempted to shew that Comparetti was the first anatomist who described this ganglion, and that he was even acquainted with the ramus auricularis of the vagus; but Arnold,§ on the other hand, maintains, and we think justly, that the description of Comparetti applies equally well, if not bettei, to the ganglion petrosum of the glosso-pharyngeal. Desmoulins and Ma gendiell observed the superior ganglion of the vagus in the carnivorous Mammalia and in the Ituminantia, and also a branch passing from it to join the portio dura, but denied that this ramus auricularis exists in man. euvier5 had also previous to this pointed out the ramus auricularis in the calf. It was not, however, until Arnold's description of this ganglion had been made public, that it became generally known to anatomists, and its true nature and its anatomical relations exactly ascertained.** Ar nold was the first who described the ramus auricularis in the human species.