t3S2 



A MANUAL OF ANATOMY 



of the opposite side, of which they form the inner and larger part. 

 The nerve-funiculi of the crossed pyramidal tract of the other side 

 are disposed in a similar manner. The ventral grey comu of 

 either side is thus broken up by the corresponding crossed pyra- 

 midal tract. Its basal pari remains on the ventral and lateral 

 aspects of the central canal, but its caput is detached and displaced 

 laterally by the pyramid and olive of the same side. 



The dorsal cornu of grey matter is gradually displaced laterally 

 and ventralwards, in the lower or closed part of the bulb, by the 

 funiculus gracilis and funiculus cuneatus. Its basal part remains 

 on the dorsal and lateral aspects of the central canal; its cervix is 

 broken up into a network by intersecting nerve-fibres ; and its caput 

 is thereby detached. The caput lies close to the detached caput 

 of the ventral cornu of grey matter, but does not blend with it. 



Substantia or Formatio Reticularis. — ^The grey matter of the de- 

 tached caput of the ventral grey cornu is broken up into a network 



Fasciculus Solitaritif 



Tola Cboroidea 



Corpus 

 Restiforme 



Formatio Reticu- 

 laris Grisea 



Formatio Reticularis Alba 



Spinal Trigeminal 

 Tract 



Rudiment of Middle Accessory Olivary 

 Nucleus 



Fig. 565. — Transverse Section of Medulla Oblongata (Keibel and 



Mall) . 



by intersecting nerve-fibres, which run longitudinally and trans- 

 versely. This reticulum, augmented by the network formed in 

 the cervix of the dorsal grey cornu, constitutes the substantia or 

 formatio reticularis of the bulb. It lies deeply within the bulb, 

 dorsal to the olive and pyramid of the same side, and it consists of 

 grey matter, longitudinal and transverse nerve-fibres, and some 

 nerve-cells. 



The funiculi of the hypoglossal nerve, as they pass forwards to 

 the ventro-lateral sulcus of the bulb, divide the formatio reticularis 

 into two parts — ^lateral and mesial. The lateral portion is situated 

 behind the olive, and is called the formatio reticularis grisea, from 

 the large amount of grey matter, with nerve-cells, which it con- 

 tains. The mesial portion is situated behind the pyramid, and is 



