152 



THE NERVOUS SYSTEM 



nucleus of Bechterew (Fig. 108), (4) the spinal or descending vestibular nucleus 

 (Fig. 103). These are represented diagrammatically in Fig. 136. 



The medial longitudinal fasciculus is an important bundle which extends 

 from near the floor of the third ventricle to the spinal cord, and is especially 

 concerned with the reflex control of the movements of the head and eyes. A 

 large proportion of its fibers are derived from the lateral vestibular nucleus. 



~M. rectus medialis 

 'i'\M. rectus lateralis 



Nucleus of med. long. fasc. 



Nucleus of oculomotor nerve 

 Nucleus of trochlear nerve 



Nucleus of abducens nerve 

 Medial longitudinal fasciculus 



r Lateral vestibular nucleus 



Vestibular nerve 



Fig. 109. Diagram showing the connections of the medial longitudinal fasciculus. (Modified 



from Villiger.) 



From this origin the fibers pass horizontally through the reticular formation to 

 the median longitudinal fasciculus of the same or the opposite side, and there 

 divide into ascending and descending branches (Fig. 109) . The former terminate 

 in the nuclei of the oculomotor, trochlear, and abducens nerve, the latter in 

 the nucleus of the spinal accessory nerve and in the columna anterior of the 

 cervical portion of the spinal cord. In this way there is established a path for 



