DISSECTION OF THE HEAD AND NECK 365 



taken place is desirable for a thorough understanding of the 

 complex relations which exist. 



Descending Fibre Systems in Spinal Cord. 



(1) Pyramidal tracts (anterior and lateral), from cortex of central gyri 



of same and opposite side. 



(2) Anterior marginal bundle from nucleus fastigii. 



(3) Sulcomarginal fasciculus = path from superior colliculus of corpora 



quadrigemina. 



(4) Descending paths in fasciculus lateralis proprius. 



(a) Tract from Deiters's nucleus to lateral funiculus. 

 (6) Tract from red nucleus of opposite side to lateral funiculus. 

 (c) Tract from nuclei laterales superior, medius, inferior, to lateral 

 funiculus. 



(5) Descending paths in posterior funiculus. 



(a) Descending limbs of bifurcation of posterior root-fibres. 



(b) Endogenous fibres of posterior funiculi (comma bundle, ven- 



tral area, oval centre, median triangle). 



(6) Other descending paths in lateral and anterior funiculi. 



(a) Endogenous fibres (tautomeric and heteromeric). 



Ascending Fibre Systems in Spinal Cord. (Vide Fig. 103.) 



(1) Direct continuation of ascending limbs of bifurcation of posterior 



root-fibres to nucleus funiculi gracilis, nucleus funiculi cuneati, 



and partly to cerebellum. 

 Secondary path: from nuclei of dorsal funiculi, through decussa- 



tio lemniscorum to stratum interolivare lemnisci of opposite side, 



and then through lemniscus median's to [ventro-] lateral nucleus 



of thalamus. 

 Tertiary path : from ventrolateral nucleus of thalamus to cortex of 



central gyri (somaesthetic area). 



(2) Fibre systems leading from the end-stations of posterior root-fibres 



in the spinal cord to higher centres, 

 (a) Cerebellospinal fasciculus (fasciculus cerebellospinalis) (0. T. 



direct cerebellar tract), from nucleus dorsalis of Clarke to 



cerebellum. 

 (6) Gowers's tract (fasciculus anterolateralis superficialis [Gow- 



ersi]), from base of anterior horn to cerebellum. 



(c) From posterior horn upward in lateral limiting layer of gray 



matter, and in opposite anterior funiculus. 



(3) Fibre systems from some of cells in anterior horns upward in fascicu- 



lus anterior proprius and fasciculus lateralis proprius to formatio 

 reticularis. 



Fibre Systems of Cerebral Nerves. 



Like the motor spinal nerves, the motor cerebral nerves arise 

 from nuclei of origin (nuclei originis) in the brain-stem, the 

 fibres leaving the central system to terminate in the muscles. 



