526 THE BRAIN 



between the posterior border of the olive and the fila of the 

 vagus and glosso-pharyngeal nerves. 



The olive is a smooth oval projection, which occupies 

 the upper part of the lateral area of the medulla oblongata. 

 Its long axis, which is vertical, is about half an inch long, 

 and its upper end is separated from the lower border of the 

 pons by an interval or groove. 



Posterior Area of the Medulla Oblongata. In its lower 

 half this region is formed by the cuneate and gracile funiculi ; 

 and in its upper half it is formed, medially, by the ependymal 

 roof of the fourth ventricle and, laterally, by the diverging 

 funiculi. 1 It is separated from the lateral area on each side 

 by the row of fila belonging to the accessory, vagus, and 

 glosso-pharyngeal nerves. 



The lower part of the posterior area corresponds more or 

 less closely with the posterior funiculi of the spinal medulla. 

 It will be remembered that in the cervical part of the spinal 

 medulla the posterior areas on each side is divided by a 

 distinct septum of pia mater into a postero-median strand and 

 a postero- lateral strand. These are prolonged upwards into 

 the medulla oblongata, and in the lower part of the posterior 

 area they stand out distinctly, and are separated from each 

 other by a continuation upwards from the medulla spinalis 

 of the postero-intermediate sulcus. In the medulla oblongata 

 these strands receive different names. The medial one is called 

 the funiculus gracilis, whilst the lateral one is designated the 

 funiculus cuneatus. Each of these strands, when it reaches 

 the lower part of the fourth ventricle, ends in a slightly 

 expanded prominence. The swollen extremity of the 

 funiculus gracilis is called the clava ; it is thrust aside from 

 its fellow of the opposite side by the opening up of the 

 central canal to form the fourth ventricle. The thickened 

 end of the cuneate funiculus receives the name of the 

 tuberculum cinereum, but it is in the young brain only that it 

 is well marked. 



In sections through this region of the medulla oblongata, 

 it is seen that the prominences produced by the two strands 

 and their enlarged extremities are in a great measure due to the 



1 The dissector should note that the lower part of the cavity of the hind- 

 brain, i.e. the fourth ventricle, is not behind but in the upper part of the 

 medulla, which it separates into dorsal and ventral parts ; the dorsal part forms 

 a portion of the roof of the ventricle, whilst the ventral part forms a portion of 

 the floor. 



