CAROTID BRANCH AND PLEXUS. 689 



a reddish tint, seeming to be in some degree a prolongation of the ganglion 

 itself. In its course to the skull, it is concealed by the internal carotid 

 artery, with which it enters the carotid canal in the temporal bone, and it is 

 then divided into two parts, which are placed one on the outer, the other on 

 the inner side of the vessel. 



Fig. 452 



Fig. 452. CONNECTIONS OP THE SYMPATHETIC NERVE THROUGH ITS CAROTID BRANCH 



WITH SOME OP THE CRANIAL NERVES. 



The full description of this figure will be found at p. 602. The following numbers 

 refer to sympathetic nerves and their connections : 6, spheno-palatine ganglion ; 7, 

 Vidian nerve ; 9, its carotid branch ; 10, a part of the sixth nerve, receiving twigs from 

 the carotid plexus of the sympathetic; 11, superior cervical sympathetic ganglion; 12, 

 its prolongation in the carotid branch ; 15, anastomosing nerve of Jacobson ; 16, twig 

 uniting it to the sympathetic. 



The external division distributes filaments to the internal carotid artery, 

 and, after communicating by means of other filaments with the internal 

 division of the cord, forms the carotid plexus. 



The inner division, rather the smaller of the two, supplies filaments to 

 the carotid artery, and goes to form the cavernous plexus. The terminal 

 parts of these divisions of the cranial cord are prolonged on the trunk of the 

 internal carotid, and extend to the cerebral and ophthalmic arteries, around 

 which they form secondary plexuses, those on the cerebral artery ascending 

 to the pia mater. One minute plexus enters the eye-ball with the central 

 artery of the retina. 



It was stated by Ribes (Mem. de la Socie"te Med. d'Emulation, torn. viii. p. 606,) that 

 the cranial prolongations of the sympathetic nerve from the two sides coalesce with 

 one another on the anterior communicating artery, a small ganglion or a plexus 

 being formed at the point of junction; but this connection has not been satis- 

 factorily made out by other observers. 



CAROTID PLEXUS. The carotid plexus, situated on the outer side of the 

 internal carotid artery at its second bend (reckoning from below), or between 

 the second and third bends, joins the fifth and sixth cranial nerves, and 

 gives many filaments to the vessel on which it lies. 



Branches. (a) The connection with the sixth nerve is established by means of one 

 or two filaments of considerable size, which are supplied to that nerve where it lies 

 by the side of the internal carotid artery. 



