478 NERVOUS SYSTEM. 



hind the. internal carotid artery, forms a ganglion, which, for 

 the purpose of description, may be considered as the first of the 

 series. This ganglion is the superior cervical. 



The nervus motor externus oculi, in passing through the ca- 

 vernous sinus, and the Vidian nerve, in passing by the point of 

 the petrous bone, both send a filament downwards through the 

 carotid canal; which two filaments unite to form a single cord, 

 that runs into the superior extremity of this ganglion. The 

 filament from the Vidian nerve is, as mentioned, the deep pe- 

 trous nerve. The common view taken by anatomists of this 

 nervous connexion is, that it is the beginning of the sympathe- 

 tic, though, by Bichat, it is described as the termination, or one 

 of its extremities. The distinction, though important physiolo- 

 gically, is less so when the object is simply to describe the course 

 and anatomical relations of this nerve, as they may be equally 

 understood by either mode of description. 



The branch from the deep Petrous most frequently forms, on 

 the external face of the internal carotid, in the cavernous sinus, 

 or more generally in the carotid canal, a ganglion, (Ganglion 

 Cavernosum, Caroticum,) discovered by Laumonier. Some ana- 

 tomists consider this ganglion to arise from one or more fila- 

 ments, from the motor externus.* From the ganglion caverno- 

 sum, it has, of late, been ascertained that filaments may bef 

 traced to the ganglion of Gasser, (Plexus Gangiiformis,) of the 

 trigeminus, to the pituitary gland, to the infundibulum ; and, 

 moreover, a fasciculus which, according to H. Cloquet, forms a 

 plexus around the ophthalmic artery, and may be traced along 

 all its branches, even the central artery of the retina. This 

 plexus anastomoses with the lenticular ganglion, and conse- 

 quently establishes a direct nervous communication between the 

 sympathetic, and the first branch of the fifth pair. The know- 

 ledge of this connexion has caused anatomists to locate the len- 

 ticular ganglion and the ciliary nerves in the ganglionic system 

 of the sympathetic, as forming a part of the latter. 



The sympathetic, in descending the neck, is placed behind 



* M. Lobstein, in his Essay on the Sympathetic, a work of much merit, has 

 attributed this ganglion to the deep petrous nerve, in which I thought for many 

 years lie was mistaken, though renewed observations have now convinced me of 

 his correctness. Paris, 1823. 



