THE MEDULLA OBLONGATA AND TEGMENTUM OF THE PONS. 209 



the facial nerve curves backward, and the entrance of the direct 

 sensory cerebellar tract into the cerebellum. In sections made 

 at this level the anterior cerebellar peduncles begin to appear. 



After the facial, the acoustic, and the abducens have left the 

 tegmentum, its conformation naturally becomes much simpler. 



We are approaching the source of the trigeminus. First, 

 in the prolongation of the nucleus of the facial, but somewhat 

 more dorsad, appears the motor nucleus of the trigeminus. From 

 it arises the motor root, the portio minor, which also takes a 



FIG. 126. 

 Section at the point where the internal division of the restiform body enters the cerebellum. 



Bindearm, Sup. cerebellar peduncle. Dir. Sena. Cer. B., Direct sensory cerebellar tract. 



slightly-curved course. This root supplies the muscles of masti- 

 cation. Probably this root also contains fibres from the opposite 

 motor nucleus which have crossed in the raplte. 



Other fibres leave the pons, together with the trigeminus, 

 which do not arise in the motor nucleus, but high up in the 

 quadrigeminal region, where a few cells at the side of the aque- 

 duct give off this descending root of the fifth nerve. (See 

 Fig. 72, above and to the left.) 



These cells are continued caudad in the lateral walls, and 

 we can see a large collection of them shining through the thin 



