VII 



THE MEDULLA OBLONGATA 



385 



The long fibres of the columns of Goll and Burdach terminate, 

 on reaching the lower part of the bulb, in two grey nuclei, one 

 lying within the column of Goll (Fig. 203 Ng\ the other externally 

 within the column of Burdach (Fig. 204 Nc). As the central 

 canal approaches the dorsal surface of the bulb, these nuclei 

 enlarge, till just above the decussation of the pyramids they form 

 the prominences termed the clavae (Fig. 205, n.g., n.c.) from the 

 ventral surfaces of which the arcuate fibres emerge, and turn 



FIG. 203. Transverse section of medulla oblongata near the decussation of the pyramids. (Henle. 

 Fpy, pyramidal tract ; Cga, ventral horn ; Fa', rest ,of ventral horn ; Ng, nucleus of funiculus 

 gracilis ; g, substantia ge'latinosa ; XI, spinal accessory. 



forwards and inwards towards the median raphe, where they cross 

 with those of the opposite side. So that above and dorsal to the 

 motor or pyramidal decussation is the sensory decussation of the 

 fibres of the fillet of Eeil or lemniscus medialis, which lies im- 

 mediately dorsal to the pyramids. 



The sensory fibres of the lateral column of the cord, which lie 

 closely related to Gowers' tract, do not decussate but continue to 

 ascend through the lateral zone of the medulla ; they pass by the 

 lateral nucleus of the bulb, and eventually join the mesial fillet in 

 the upper portion of the medulla or in the pons. 



The cerebellar tracts of the lateral columns pass through the 

 restiforni body or the inferior cerebellar peduncle, and terminate 

 in the cerebellar cortex. 



VOL. in 2 c 



