CONNECTIONS OF THE LONG PATHS OF THE CORD 845 



of the fibres: the fibres from the lowest segments of the cord lie 

 outermost; beneath these come fibres from the lowest thoracic seg- 

 ments, then fibres from the higher thoracic segments; and, internal 

 to all, fibres from the topmost thoracic and lowest cervical segments. 



Connections of the Antero-Lateral Ascending Tract. According to 

 Schafer, the axons of this tract are probably connected with cells 

 situated in the middle and posterior parts of the grey crescent, mainly 



n.c 



u.mj. 



Fig. 340. Transverse Section of Medulla 

 Oblongata at the Level of the Decussa- 

 tion of the Fillet (Halliburton, after 

 Schwalbe). a.m.f, anterior, and p.m.f, 

 posterior, median fissure; f.a and /.a 2 , 

 external arcuate fibres; f.a', internal 

 arcuate fibres becoming external; n.a.r, 

 nuclei of arcuate fibres; py, pyramid; 

 o, o', lower end of nucleus of olive; f.r, 

 formatio reticularis; n.l, lateral nucleus; 

 n.g, nucleus gracilis; f.g, funiculus gra- 

 cilis; n.c, nucleus cuneatus; n.c', external 

 cuneate nucleus; /.c, funiculus cuneatus; 

 g, substance of Rolando; c.c, central canal 

 surrounded by grey matter ;. XI, nucleus 

 of spinal accessory; n.XII, of hypoglos- 

 sal; a.V ', ascending root of fifth nerve; 

 s.d, the decussation of the fillet, or 

 superior decussation. 



n.ar. 



Fig. 341. Transverse Section of Medulla 

 Oblongata at about the Middle of the 

 Olive (Schwalbe). f.l.a, anterior median 

 fissure; n.a.r, arcuate nucleus; p., pyra- 

 mid; n.XII, hypoglossal nucleus; XII, 

 root bundle of hypoglossal nerve coming 

 off from the surface ; at 6 it runs between 

 the pyramid and the dentate nucleus of 

 the olive, o; f.a.e, external arcuate fibres; 

 n.l, lateral nucleus; a, arcuate fibres going 

 to restiform body c.r, partly through the 

 substantia gelatinosa g, partly superficial 

 to the ascending root of the fifth nerve 

 a.V; X, root-bundte of vagus; n.X, n.X', 

 two portions of vagus nucleus; f.r, for- 

 matio reticularis; n.g, nucleus gracilis; 

 n.c, nucleus cuneatus; n.t, nucleus of the 

 funiculus teres; n. am, nucleus ambiguus; 

 r, raphe; o', o", accessory olivary nucleus; 

 p.o.l, peduncle of the olive. 



on the opposite side of the cord, although also on the same side. None of 

 the fibres of the tract can come directly from the posterior nerve-roots, 

 since no degeneration is seen in it on section of the roots alone. 



The antero-lateral ascending tract passes up through the medulla, 

 where some of its fibres perhaps form synapses with the cells of the 



