PEDUNCLES OF THE CEREBELLUM 



811 



olive of the same and opposite side of the meduUa oblongata; (3) fibres from the nuclei of the 

 funiculus gracUis and cuneatus of the same and opposite sides; (4) fibres to and from the 

 olive of the opposite side; (5) fibres to the nuclei of the motor cranial nerves; (6) fibres 

 descending to the ventral horn cells of the spinal cord. The ascending or afferent fibres of the 

 spino-cerebellar and cerebeUo-ohvary fasciculi are the principal components of the inferior ped- 

 uncle; the existence of fibres (5) and (6) is not weU estabhshed. Of these, the fibres of the direct 

 cerebellar tract terminate in the cortex of the superior vermis of both sides of the mid-fine, but, 

 for the most part, in that of the same side. The olivary fibres end in the cortex of both the su- 

 perior vermis and .the adjacent cortex of the hemispheres, and some of them terminate in the 

 nucleus dentatus. 



The brachium pontis or the middle peduncle is the largest of the three cere- 

 bellar peduncles. In it the pons fibres pass slightly downward and into the cere- 

 bellar hemisphere, between the lips of the anterior part of the horizontal fissure, 

 entering lateral to the inferior peduncle. 



Fig. 638. — Transparency Drawing Showing the Origin, Course, and Connections op the 

 Superior Cerebellar Peduncles (Brachia Conjunctpva) in the Formation op 

 'Stilling's Scissors.' 



Thalamus 

 -\- - Internal capsule 



Brachium conjunctivum 

 "^^_~ " (superior peduncle) 



Bundle from red nu- 

 cleus to thalamus 



«• Bundle from red nucleus to 



internal capsule 

 * Red nucleus 

 Decussation of brachia conjunctiva 



Inferior peduncle 

 (restiform body) 



Bundle to cerebellar 



cortex 

 — Dentate nucleus 



It consists of the transverse fibres of the pons, and within the cerebellum its fibres are dis- 

 tributed in two main groups — the upper transverse fibres of the pons apparently pass downward 

 to radiate in the lower portion of the hemisphere, while the lower transverse fibres pass upward 

 and medialward to radiate in the superior part of the hemisphere and vermis. For the most 

 part the fibres of the middle peduncle ma}^ be considered as commissural fibres, passing from 

 one side of the cerebellum to the other. Each peduncle contains fibres coursing in opposite 

 directions. Many of these fibres are interrupted in their course to the opposite side by cells 

 scattered throughout the pons, nuclei of the pons, and, therefore, in each brachium pontis some 

 of the fibres are processes of the cells of the cerebellum and course toward the opposite side, 

 while others are processes of the cells of the pontine nuclei and course to the cerebellar hemis- 

 phere of the same side. Many cell-bodies of the nuclei of the pons whose axones terminate 

 in the cerebellum receive impulses from fibres descending from the cerebral cortex of the opposite 

 side — -cortico-pontine fibres. Furthermore, there are evidences after degeneration that the 

 brachium pontis also contains a few fibres from the cerebellum to the structures of the brain- 

 stem and spinal cord. 



