308 NEUROLOGY, OR ANATOMY OF NERVOUS SYSTEM 



In front and behind it is marked by the continuation of 

 the anterior and posterior median fissures of the cord, the 

 former, with its process of pia mater, ending in a cul-de-sac 

 just below the pons, the foramen cecum. The posterior expands 

 into the fourth ventricle. 



Each lateral half of the medulla is divided into areas. 



The areas of the medulla oblongata are: (1) Ventral area; con- 

 taining the pyramid. (2) Lateral area; containing the lateral 

 tract olive. (3) Dorsal area; containing the funiculus gracilis, 

 funiculus cuneatus, funiculus lateralis and tuberculum cinereum. 

 (Gray.) 



The restiform body succeeds the gracile and cuneate nuclei 

 in the dorsolateral part of the medulla oblongata. Its fibers 

 converge from various sources and ultimately enter the cere- 

 bellum as its inferior peduncle. (Gray.) 



The Decussation of the Pyramids. It is a term applied to 

 the interlacing bundles seen on the ventral aspect of the medulla, 

 at the junction of the medulla and the spinal cord. Ninety 

 per cent, of the fibers cross the median line in this decussation 

 to continue as the crossed pyramidal tract. 



SUMMARY OF THE GRAY MASSES IN THE MEDULLA 



OBLONGATA 



Central tubular gray (in "closed" part). 



Gray floor of fourth ventricle (in "open" part). 



Gelatinosa Rolandi, or gliosa. 



Nucleus funiculi gracilis. 



Nucleus funiculi cuneatus. 



Nucleus funiculi cuneati accessorius. 



Nucleus lateralis. 



Nucleus olivarius inferior. 



Nucleus olivarius accessorius dorsal is. 



Nucleus olivarius accessorius medialis. 



Nucleus arcuatis. 



Nucleus nervi hypoglossi. 



Nucleus intercalates. 



Nucleus postremus. 



Nucleus vagi (ala cinerese). 



Nucleus vestibularis (spinal division). 



