;NTEENAL STKUCTUKE OF MEDULLA OBLONGATA AND PONS. 56i 



ream forwards and medially towards the median raphe, forming a series of con- 

 ntric curves in the substance of the medulla oblongata. They cross the median 

 ane and decussate 



ith the COrre- Gracile nucleus. 



lending fibres of 

 ie opposite side, 

 :>on the dorsal 

 ipect of the pyra- 

 ids. Having 

 i us gained the 

 )posite side of the 

 edulla oblongata, 

 ley immediately 

 irn upwards and 

 >rm a conspicuous 

 rand of longi- 

 idinal fibres, 

 hich ascends close 

 i the median plane 

 id is separated 

 om its fellow of 

 i e opposite side 

 Y the median 

 ,phe alone. This 

 rand is termed 

 ie lemniscus 



FIG. 494. TRANSVERSE SECTION THROUGH THE HUMAN MEDULLA OBLONGATA 

 As we proceed up IN THE INFERIOR OLIVARY REGION. 



e medulla oblon- 



internal arcuate fibres which first come into sight appear as coarse bundles which 



Funiculus cuneatus 



Cuneate nucleus 



Tractus solitarius 



Tractus spinalis of 



trigeminal nerve 



Nucleus of 



tractus spinalis- 



of trigeminal nerve 



Internal arcuate 



fibres 



Fila of hypoglossal 

 nerve 



External 

 arcuate fibres 



Inferior olivary 

 nucleus 



Medial accessory 

 olivary nucleus 



Pyramid 



External 

 arcuate fibres 



Restiform borly 



Vago-glossopharyugeal 

 roots 

 I Nucleus of the 



Fasciculus tectospinalis 



Vagus n ucleus 



Tractus sulitarius 



Descending root of vestibular nerve 



go-glossopharyngeal roots 



Fasciculus spinocerebellaris 

 posterior 



Fasciculus longitudinalis 



medialis 



Nucleus tractus spinalis 



nervi trigemini [nerve 



tus spiuulis of trigeminal 

 Nucleus ambiguus 



iculus rnbrospmalis 

 o-cerebellar fibres 



Fasciculus spinothalainicua 

 rsal accessory olivary nucleus 



iculus spinocerebellaris anterior 

 External arcuate fibres 

 Lemniscus medialis 



Medial accessory olivary nucleus 

 Fasciculus tegmento-olivaris 

 Inferior olivary nucleus 



Pyramid 



1 External arcuate fibres 



TRANSVERSE SECTION 'THROUGH THE MIDDLE OF THE OLIVARY REGION OF THE HUMAN MEDULLA 



OBLONGATA. 



The floor of the fourth ventricle is seen, and it will be noticed that the restiform body on each side has 

 now taken definite shape. Some of the descending tracts in red ; ascending tracts in blue. 



fe forwards in a narrow group round the central gray matter (Figs. 494 and 495). Soon, 

 her finer bundles appear, which describe wider curves on the lateral side of the coarser 



37 



