784 



THE NERVOUS SYSTEM 



appear ribbed, owing; to bundles of the external arcuate fibres passing across them 

 to and from the restiform body, which occupies the extreme lateral portion of the 

 medulla. Along the line between the restiform body and the olives are attached 

 the root filaments of the vagus, gloeso-pharyngeal, and spinal accessory nerves. .Both 

 the abducens and the facial nerve emerge along the border of the pons, the facial in 

 line with the glosso-pharyngeal, but the abducens in line with the hypoglossus. 



Dorsal aspect. The increased lateral diameter of the medulla oblongata is 

 contributed to a great extent by the restiform bodies. These are the inferior cere- 

 bellar peduncles, and contain the majority of both the ascending and the descend- 

 ing fibres, which connect the cerebellum with the structures below it. In toto, the 

 restiform bodies are much larger than could be formed by the combined cerebellar 



FIG. 581. DIAGRAM SHOWING THE DECUSSATION OF THE PYRAMIDS. 

 The uppermost level represented is near the inferior border of the pons. 



TEL.l CHORIOIDEA OF FOURTH 



Vl.STUK'LE 

 SOLITARY TRACT 



._- KUCLEUfi X. VEKTIBULI 

 ( I'//) 



- RESTIFORM BODY 



.. Sl'lXAI. TRACT OF TRI- 



osxruus 



NUCLEUS X. COCHLEARES 



( 



VA G us 



X. IIYPOGLOSSUS 

 PYRAMID 



SPINA L TRACT OF TRIGEMINUS 



DECUSSATION OF PYRAMIDS 



LATERAL CEREBRO-SPINAL 



FASCICULUS (crossed pyramidal 

 truct) 



. VENTRAL CEREBRO-SPINAL 

 FASCICULUS (direct pyramidal 

 tract) 



fasciculi of the spinal cord, their great size being due to their receiving numerous 

 axones coursing in both directions, which connect the cerebellum with structures 

 contained in the medulla oblongata alone, so that in the medulla they increase as 

 they approach the cerebellum. Their name (restiform meaning rope-like) was sug- 

 gested from the appearance frequently given them by the fibres of the cochlear 

 (acoustic) division of the eighth cranial nerve, which course around their lateral 

 periphery to become the stria; medullares acustici in the floor of the fourth ventricle. 

 Upon removal of the cerebellum it may be seen that below the calamus scrip- 

 torius (inferior terminus of the fourth ventricle) the structures manifest in the dor- 

 sal surface of the medulla are directly continuous with those of the spinal cord. The 

 fasciculus gracilis (Goll's column) of the spinal cord acquires a greater height and 

 volume and becomes the funiculus gracilis of the medulla, and because of this 



