732 



DISSECTION OF THE BRATN. 



Pyramid . 



position of which is occupied in the upper half of the bulb by ar: 

 oval eminence called the olivary body. Continuing the posterioij 

 column is the funiculus cuneatus (fig. 262, /c), which is separatee 

 from the lateral tract by a smaller eminence to which the name o 

 funiculus of Rolando (R) has been given : in the upper part of th( 

 medulla these are succeeded by, or become lost on, the restiform body 

 (fig. 261, 3 ; fig. 262, rb) projecting outwards towards the cerebellum 

 And lastly, between the funiculus cuneatus and the posterior medial 

 fissure is the funiculus gracilis (fig. 262, /</) continued from tht 

 posterior median column of the cord. 



The anterior pyramid is placed between the anterior median fissure 



on the inner side and the latera 

 tract with the olivary body on th( 

 outer side. It increases in size fron 

 below upwards, whence its name 

 but at the upper end it is somewha 

 constricted and rounded just befor< 

 it disappears beneath the superficial 

 transverse fibres of the pons. This 

 body is only in small part pro- 

 longed from the anterior column o 

 the cord, its inner and larger por- 

 tion being formed by the decussating 

 fibres seen in the anterior median 

 fissure. 



The lateral trad in the lower hall 

 of the medulla oblongata is of the 

 same width as the lateral column 

 of the cord ; but above, it is reduce c 

 to a narrow strip along the botto 

 of the groove between the olivarv 

 and restiform bodies. 



The olivary body is oval in shape 

 and about half an inch long. Its 

 upper end, which is more prominent 

 than the lower, does not quite reach 

 the pons. Internally it is separated 

 a narrow groove along which the 



hypoglossal nerve arises ; and externally from the restiform body 

 by a broader one, where the glosso-pharyngeal and vagus nerves 

 issue. 



The funiculus of Rolando begins in a pointed extremity at the 

 of Rolando, lower end of the medulla oblongata, and enlarging upwards forms, 

 on a level with the lower end of the olivary body, a slight prominence 

 known as the tubercle of Rolando. Towards the front this funiculus 

 is separated from the lateral tract by the continuation upwards of 

 the lateral groove of the cord ; but posteriorly the line of separation 

 from the cuneate funiculus is often indistinct. The funiculus and 

 tubercle of Rolando are better marked in the child, and the tubercle 



Lateral 

 tract. 



Olive. 



FIG. 261. MEDULLA OBLONGATA 

 AND PONS FROM BEFORE. 



1. Pyramid. 



2. Lateral tract. 



3. Restiform body. 



5. Olivary body. 



6. Decussation of pyramids. 



from the anterior pyramid by 



Funiculus 



and tubercle 



