274 



FIFTH PAIR OF NERVES. 



apparently contrary to analogy ; they are dis- 

 tinguishable into anterior and posterior, but 

 they descend, the anterior to the posterior, and 

 the posterior to the anterior columns. The an- 

 terior cord is by much the larger, and is pro- 

 longed through the inferior peduncle of the 

 cerebellum, until at the inferior extremity of 

 the bulb it is continued into the longitudinal 

 fasciculi of the corresponding posterior column 

 of the spinal marrow ; it is situate along the 

 outer side of the olivary body, but separated 

 from it by a slight interval, nor does it seem 

 to have any connection with that body : it is 

 imbedded in the substance of the superior part 

 of the peduncle, situate, however, nearer to its 

 anterior than its posterior surface, and laid 

 obliquely across its fibres as they pass outward 

 toward the hemisphere of the cerebellum; but 

 as it proceeds it becomes gradually more super- 

 ficial, gains the outer side of the peduncle, and 

 at the lower extremity of the bulb is actually at 

 its surface almost immediately behind the lateral 

 fissure of the cord and the posterior roots of the 

 superior cervical nerves. The existence and 

 course of this cord have been first established 

 and described by Rolando in his "Saggio sopra 

 la vera Struttura del Cervello," and also in a 

 memoir upon the Anatomy of the Medulla 

 oblongata, published in the fourth volume of 

 the Journal of Physiology. 



The posterior cord is much smaller than the 

 former ; it descends behind the inferior pedun- 

 cle of the cerebellum, as it passes outward 

 into the hemisphere, and upon the posterior 

 aspect of the spinal bulb ; enters the posterior 

 fissure of the bulb, between the posterior py- 

 ramids, and can be traced some way down- 

 ward, in the bottom of the fissure, along the 

 back of the anterior column of the same side, 

 into which it appears to be ultimately con- 

 tinued. (Figs. 140, 141, 13.) 



The preceding account of the encephalic 

 connections of the fifth nerve differs very much 

 from that adopted by some of the highest 

 modern authorities. It is not necessary to 

 allude to the opinions entertained upon the 

 point, before the course of the nerve had 

 been particularly inquired into; but, accord- 

 ing to some of the most recent, the nerve 

 arises from the groove between the restiform 

 and olivary bodies, and from the olivary bodies 

 themselves. Such is the view given of the 

 origin of the nerve by Gall and Spurzheim 

 in their fifth plate of the brain, in which the 

 nerve is represented breaking up, on the out- 

 side of the olivary body, into several fasciculi, 

 which plunge obliquely into it. In their 

 account* of the course of the nerve into the 

 brain they state, " on peut aisement suivre son 

 cours entier jusq'au dessous du cot^ exteVieur 

 des corps olivaires ;" this might be, perhaps, 

 interpreted to mean beyond the olivuries, 

 reference being had to the relations of those 

 bodies in the erect posture ; but from the 

 representation given it is obvious that the in- 

 tended meaning is, that the nerve can be fol- 



* Anatomic et Physiologic du Systcme Ner- 

 vmx, torn. i. p. 107. 



lowed to beneath, i. e. underneath, their outer 

 side, the brain being placed in the manner 

 ordinarily adopted for dissection, in which 

 the anterior aspect of the olivaries is rendered 

 superior; indeed their representation is alto- 

 gether incompatible with the opinion that they 

 had traced the nerve beyond the bodies. 



Such also is the opinion of J. F. Meckel,* 

 according to whom the nerve " passes under 

 the posterior peduncle of the cerebellum, 

 along the outer side of the pons, toward the 

 groove between the olivary and restiform bo- 

 dies, where it arises in part from the groove 

 and in part from the olivary eminences." 

 Cloquetf likewise states the nerve to arise 

 between the olivary and restiform bodies, and 

 has adopted and copied, in his late work,} 

 the view given of its origin by Gall and Spurz- 

 heim. Further, the discovery of this origin of 

 the nerve has been attributed by Meckelj and 

 others to Santorini. 



It is a hardy thing to contradict such au- 

 thorities as have been quoted, and the influence 

 which they justly carry with them has made 

 the author hesitate before adopting a contrary 

 opinion ; but if reference be made to the work|| 

 of Santorini on the point, it will be found that 

 he nowhere, in his account of the origin of the 

 nerve, assigns the groove between the restiform 

 and olivary bodies as its situation in the spinal 

 bulb, as will appear from the following extract, 

 the only paragraph of his account in which he 

 particularizes it, and in which he supposes it 

 to be situate between the olivary and pyramidal 

 bodies : " Unde in interiorem medulla ob- 

 longatse caudicem conjectus, fere inter olivaria 

 et pyramidalia corpora locatus, quo demum 

 pergat, cum tenuium fibrarum implexus, turn 

 earumdem mollitudo, ne consequerer, omnino 

 prohibuere ;" from which it is plain, as has 

 been stated, that he supposed the nerve to be 

 between the two latter bodies ; and also that 

 he had not been able to trace it to any particular 

 destination, although, in a succeeding para- 

 graph, he conjectures the olivary body to be 

 its source : hence there is reason to conclude 

 that succeeding anatomists have assumed his 

 conjecture to be an established fact, and have 

 modelled their accounts and representations 

 accordingly. Moreover, since the olivary bodies 

 do not exist in the lower classes of animals, 

 it is not likely that they should be points of 

 origin or attachment for nerves ; in fine, the 

 author has so uniformly succeeded in tracing 

 the nerve to the destination which has been 

 described, that he is satisfied of the accuracy 

 of it, in which he is confirmed by the fact that 

 the account here given accords with the opinions 

 of Santorini, Sremmerring, and Rolando, so 

 far as that of the first has been determined to 

 be accurate, or as those of the others extend : 

 the particulars in which it differs from, or rather 

 in which it goes beyond these, rest upon the 

 author's authority and remain to be confirmed, 



* Manuel d'Anatoroie, French edit, 

 t Traite d'Anatomie descriptive. 

 J Anatomic de 1'Homme, 

 4 See note 5, p. 82, op. cit. vol. <i. 

 || Observations Anatomicx. 



