ANATOMY AND PHYSIOLOGY OF NERVOUS SYSTEM. 



ANTERIOR PYRAMIDS. On each side of the median groove are 

 located two white columns, which are slightly swollen at their upper 

 ends and have the appearance of clubs. These columns are the 

 anterior pyramids. 



OLIVES. Just outside of the upper portion of the pyramids are 

 two prominent, oval masses whose longer axes are vertical. These 

 bodies measure about one-half inch in length and one-fourth in 

 breadth. They are the inferior olives. They are prominences added 

 to the medulla, and do not have any similar portions in the spinal 

 cord. The olives are separated from the pyramid in front by a 

 groove; in this latter is embodied the continuation of the false 

 antero-lateral groove. In it is found the apparent origin of the 

 hypoglossal nerve. Behind, the olives are separated from the resti- 

 form bodies by another groove : a continuation of the postero-lateral 

 groove of the spinal cord. From it emerge the glosso-pharyngeal, 

 the vagus, and the spinal accessory. At their lower edge these 

 grooves are somewhat effaced by the white arcuate fibers of the olive ; 

 these latter ascend in the restiform bodies. 



EESTIFORM BODY. Back of the postero-lateral groove of the 

 medulla, and therefore on its posterior surface, is found a large 

 column of white substance: the restiform body. It seems to be con- 

 tinuous below with the posterior columns of the cord; above with 

 the inferior peduncle of the cerebellum. These columns form part 

 of the anterior as well as lateral aspects of this organ. 



Posteriorly it is seen that the inferior third of the medulla is 

 very different from the upper two-thirds. The inferior third is 

 similar to the cord in that it possesses a posterior median groove 

 continuous with that of the cord ; on each side of ^t are two white 

 columns. They are continuations of the posterior columns of the 

 cord. 



At the base of the groove is found the gray commissure. 



In the upper two-thirds of the medulla this form is much 

 inged. Here the posterior columns take the name of restiform 

 lies, or inferior peduncles of the cerebellum. Instead of pursuing 



irallel course, they diverge from one another in such a manner 

 to leave between them at their upper end a V-shaped surface, 

 le surface included within this angular space comprises gray mat- 

 It forms the lower half of the floor of the fourth ventricle. 

 le upper, angular portion is formed by the posterior face of the 

 is. 



The beginning of divergence of the restiform bodies presents 



