

THE STRUCTURE OF THE BRAIN STEM 

 spending to the anterior basis bundle, i.e. that Dart of tl 

 occupied chiefly by intra-spinal fibres,' is thus ffi1 

 final y comes to he immediately beneath the grey matter of the to of the 

 fourth ventricle. Immediately dorsally to the fillet is to be seen 1 othe 



;='C.OI. Fibres 



FIG. 184. Diagram to show the sources of the fibres making up the restiform body. 



Ar.N, arcuate nucleus; Ar fibres, arcuate fibres; Pyr, pyramid; C.Sp. 

 Tract, direct cerebellar tract; C.01 fibres, cere bello-oli vary fibres; Pl.B, 

 posterior longitudinal bundle ; DN, nucleus of Deiters ; NB, nucleus of Bech- 

 terew ; Ro.N, roof nuclei ; Vest. N, vestibular nerve. 



well-marked bundle of longitudinal fibres, known as the posterior longi- 

 tudinal bundle. These fibres, which serve to connect the nuclei of many of 

 the cranial nerves, can be regarded as analogous to the constituent fibres of 

 the anterior basis bundle in the cord, and can in fact be traced into this part 

 of the anterior columns in the first and second cervical segments of the cord. 



The fourth ventricle is covered in by the cerebellum, which is 

 attached to the axial part of the brain by three peduncles, the inferior 

 peduncles or restiform bodies, the lateral peduncles, which form the great 

 mass of transverse fibres known as the pons Varolii, and the superior 



