THE STRUCTURE OF THE MEDULLA OBLONGATA 



which becomes split up into several bundles (Fig. 103). They form an im- 

 portant group of internal arcuate fibers, which run through the restiform body 

 to the cerebellum and constitute the olivocerebellar tract (Fig. 104). 



The restiform body or inferior cerebellar peduncle is a large and prominent 

 strand of fibers which gradually accumulate along the lateral border of the 

 caudal part of the fourth ventricle. It forms the floor of the lateral recess of 

 that cavity and then turns dorsally into the cerebellum (Figs. 88, 89, 103). It 

 is composed for the most part of two large and important fascicles: (1) the 



-'Restiform body 

 - -Olivocerebellar tract 

 'Lateral reticular nucleus 



Medulla oblongata < 



Spinal cord 



""Arcuate fibers from arcuate 

 nucleus 



Dorsal external arcuate fibers 



Dorsal spinocerebellar tract 



Fig. 104. Diagram showing the fiber tracts which enter the restiform body from the medulla 



oblongata. 



olivocerebellar fibers, both direct and crossed, but chiefly from the inferior olivary 

 nucleus of the opposite side; and (2) the dorsal spinocerebellar tract, from the 

 nucleus dorsalis of the same side of the spinal cord (Fig. 104). In addition, 

 there are fibers in smaller number from other sources: (3) the dorsal external 

 arcuate fibers from the gracile and cuneate nuclei of the same side; and fibers 

 (4) from the arcuate nucleus, (5) from the lateral reticular nucleus, and possibly 

 also from other cells scattered through the reticular formation (Van Gehuchten, 

 1904). 



