636 



STRUCTURE OF THE BULB, PONS, AND MID-BRAIN [CH. XLIV. 



are connected with fibres of the trapezium, while some of their axons 

 pass into the adjacent lateral part of the fillet. 



The nucleus of Deiters (n. VIII, fig. 464) begins to appear in the 

 upper part of the bulb, and extends into the pons ; it lies near the 

 floor of the ventricle, a little mesial to the restiform body. The 

 nerve-fibres connected with its cells pass towards the middle line, 

 and enter the posterior longitudinal "bundle, which is more clearly seen 



vm 



FIG. 464. Section across the pons, about the middle of the fourth ventricle, py., pyramidal bundles ; 

 po., transverse fibres passing po l behind, andpo ? , in front of py; r., raphe ; o.s., superior olive; 

 a. V., bundles of motor root of V. nerve enclosed in a prolongation of the substance of Rolando; t, 

 trapezium ; VI., the sixth nerve, n. VL, its nucleus ; VII., facial nerve; VII. a., intermediate por- 

 tion, n. VII., its nucleus; VIII. , auditory nerve, n. VIIL, Deiters' nucleus formerly called the 

 lateral nucleus of the auditory. (After Quain.) 



in the two next sections (fig. 465). This bundle of fibres connects 

 Deiters' nucleus, the nucleus of the third and sixth nerves, and the 

 anterior horn cells of the spinal cord. The fibres which pass into it 

 from Deiters' nucleus bifurcate, one branch passing upwards to 

 arborise around the cells mainly of the oculo-motor nucleus of the 

 opposite side ; the other extends downwards through the bulb into 

 the cord, where they are found in the antero-lateral descending tract 

 of each side. They terminate by synapses around the anterior horn 

 cells. 



This bundle receives in addition to the fibres from Deiters' nucleus, other fibres 

 from the sensory nucleus of the fifth nerve, and from large cells in the reticular for- 

 mation of mid-brain, pons, and bulb. 



The nerves which are connected with the grey matter of this 

 region of the pons are the sixth, seventh, and eighth, as shown in the 

 diagram. The nuclei in connection with the fifth nerve are higher 



