426 



SYMPATHETIC NERVE. 



Krause describes branches as passing across 

 the bodies of the vertebrae, forming a com- 

 munication between the ganglia of opposite 

 sides. 



IV. Sacral portion of the Gangliated Cord. 

 The sacral portion of the sympathetic cord 

 is situated towards the inner side of the 

 sacral foramina. The ganglia are commonly 

 four in number, are smaller than those in the 

 lumbar region, and decrease in size from above 

 downwards : the cords of opposite sides con- 

 verge as they pass to the lower extremity of 

 the sacrum, and unite together in front of 

 the coccyx, there being frequently present at 

 their point of union a small ganglion, from 

 which one or two filaments of communica- 

 tion pass to the fifth sacral and coccygeal 

 nerves. The branches connected with the 

 sacral ganglia are communicating brandies 

 with the spinal nerves, commonly two in 

 number for each. Several delicate filaments 

 are also sent to the inferior hypogastric 

 plexus. 



PLEXUSES OF THE SYMPATHETIC. 



A. In the Head. The chief plexuses of 

 the sympathetic which exist in the head are 

 the internal carotid plexus, cavernous, and 

 external carotid. There are also present in 

 different parts of the head several ganglia : 

 the principal of these are the ciliary ganglion, 

 spheno-palatine, otic, and submaxillary. These 

 ganglia have been already described in this 

 work in the articles on the different nerves 

 with whose branches they are connected. 



1. Internal Carotid Plexus. The internal 

 carotid plexus is formed by the ascending 

 branches of the superior cervical ganglion, and 

 surrounds the internal carotid artery during 

 its passage through the carotid canal. The as- 

 cending branch of the superior cervical gan- 

 glion, as was already stated, divides into two 

 portions, one of which passes along the outer 

 and anterior aspect of the artery, while the 

 other lies on the inner and posterior aspect of 

 the same vessel. The external portion is chiefly 

 concerned in the formation of the carotid 

 plexrs, the inner in forming the cavernous 

 plexus. The carotid plexus is thus situated 

 chiefly on the outer side of the artery between 

 its second and third bends. The branches 

 connected with the plexus are, 



() Two or three filaments of communica- 

 tion with the sixth pair of nerves ; they join 

 the nerve as it passes along the cavernous 

 sinus. One of these, stronger than the others, 

 was formerly regarded as one of the roots of 

 the sympathetic nerve. One filament is said 

 sometimes to run only a short distance with 

 the sixth nerve, when it leaves it and passes 

 to the ciliary ganglion, or to the spheno-pala- 

 tine. 



(6) Great or deep Pctrosal Nerve. This 

 branch, commonly termed the deep branch of 

 the Vidian nerve, may be regarded as passing 

 from the fifth pair to the sympathetic, or vice 

 versa. Regarding it as the latter, it may be 

 described as passing out by the superior ori- 



fice of the carotid canal, traversing the car- 

 tilaginous substance which occupies the an- 

 terior lacerated foramen to reach the pterygoid 

 canal, where it becomes associated with the 

 cranial division of the Vidian, along with 

 which it traverses the canal from behind for- 

 wards, and terminates in the ganglion of 

 Meckel. In the interior of the pterygoid 

 canal, the two nerves are merely placed side 

 by side witli each other, and after leaving the 

 canal are connected separately with the gan- 

 glion. The greater or deep petrosal nerve 

 was formerly regarded as the second of the 

 two roots by which the sympathetic was sup- 

 posed to begin. 



(c) From three to five delicate short branches 

 pass through the outer wall of the cavernous 

 sinus and join the Oasserian ganglion on its 

 inner surface. One or two of these have been 

 described as passing backwards to the ten- 

 torium cerebelli, and have been traced by 

 Arnold to the walls of the transverse sinus. 

 The filaments to the Gasserian ganglion are 

 sometimes supplied by the cavernous plexus. 



2. Cavernous Plexus. This name is applied 

 to the plexus formed around the internal 

 carotid artery as it lies in the cavernous sinus; 

 it is situated rather towards the inner surface 

 of the vessel, at the point where it makes its 

 highest turn. 



The branches which leave the cavernous 

 plexus are the following: (a) Filaments 

 which join the third nerve; they are two or 

 three in number, and become united with the 

 nerve before its entrance into the orbit. Hirzel 

 regards the communication as rare, having 

 found it only in ten bodies ; in some cases he 

 found that the supposed nerve filaments con- 

 sisted merely of cellular tissue. Bock, Longet, 

 and others regard it as constant. (6) Branches 

 of communication to the fourth nerve ; they 

 are either derived from the cavernous plexus 

 or from the carotid, and join the nerve as it 

 lies in the cavernous sinus, (c) Communi- 

 cating filaments with the ophthalmic ganglion, 

 one or two in number, emerge from the an- 

 terior part of the cavernous plexus, and enter 

 the orbit on the inner side of the ophthalmic 

 division of the fifth nerve, either ending di- 

 rectly in the posterior border of the ophthalmic 

 ganglion, or joining the long root derived from 

 the nasal branch of the ophthalmic. Occa- 

 sionally one filament enters the posterior bor- 

 der of the ganglion, the other along with 

 the long root derived from the nasal branch. 

 ((/) One or two delicate filaments have been 

 observed by Fontana, Hirzel, and Arnold to 

 pass from the cavernous plexus to the pituitary 

 body. As this body is said to receive filaments 

 from the sympathetic cords of either side, 

 it has been supposed to hold the same rela- 

 tion to these as the ganglion impar or coccy- 

 geal ganglion at the opposite extremity of the 

 trunk. Bock regards the filaments, however, 

 which have been described as entering the 

 pituitary body, as solely destined for its ves- 

 sels, terminating in their coats. Weber states 

 that he has examined with the greatest care 



