CHAP. XXIII.] 



OF THE HUMAN BRAIN. 



463 



be made up by the centripetal prolongations of the Audi- 

 tory Nerve ; the fibres of which are traceable from its own 

 ' external nucleus ' to the ' nucleus du toit ' of Stilling on 

 the same and on the opposite side. But the outer portion 

 of the Pedun- 

 cle, Meynert 

 says, is de- 

 rived from the 

 opposite ' pos- 

 terior column' 

 of the Cord in 

 the following 

 manner. The 

 fibres of the 

 posterior me- 

 dian column 

 ( ' funiculus 

 cuneatus et 

 gracilis ') en- 

 ter or come 

 into relation 

 with the gang- 

 lion cells of 

 the corres- 

 ponding ' oli- 

 vary body ' ; 

 thence they 

 cross the me- 

 dian line of 

 the Medulla, 

 behind the 



* anterior pyramids,' to pass round the opposite olivary 

 body before emerging in the form of ' arcuate fibres ' at 

 the posterior and lateral region of the Medulla. Here they 



FIG. 166. The Middle Cerebellar Peduncles and. Pens, 

 with Contiguous Parts. (Sappey, after Hirschfeld.) 1, 

 Optic Commissure ; 2, Tuber Cinereum and Pituitary ped- 

 icle ; 3, Corpora mammillaria ; 4, Inter-peduncular space ; 

 5, Cerebral peduncle ; 6, 6, Median groove on Pons, with (7) 

 a slight prominence on each side; 8, origin of the trige- 

 minus ; 9, superior transverse fibres of the Pons ; 10, 10, its 

 median fibres ; 11. its lower fibres dipping beneath the for- 

 mer; 12, 12, middle Cerebellar peduncles, formed by the 

 union of these three sets of fibres; the left peduncle is 

 divided near its origin, the right is in part dissected out. 

 13, Spinal Cord ; 14, median furrow of the Medulla ; 15, 15, 

 decnssation of the pyramids (16) ; 17, Olivary body ; 18, Arci- 

 form fibres. 



