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HANDBOOK OF PHYSIOLOGY. 



i. the posterior pyramid, or fasciculus gracilis, which is a continuation 

 of the posterior median column, and by ii. the restiform body, comprising 

 the funiculus cuneatus and the funiculus of Rolando. The fasciculus 

 gracilis (Fig. 337, /.#), diverges above as the broader clava to form one 

 on either side the lower lateral boundary of the fourth ventricle, then 

 tapers off, and becomes no longer traceable. The funiculus cuneatus, 

 or the rest of the posterior column of the cord, is continued up in the 

 medulla as such (Fig. 337, f.c); but soon, in addition, between this and 

 the continuation of the posterior nerve-roots, appears another tract called 

 the funiculus of Eolando (Fig. 337, f>R}. High up, the funiculus cune- 

 atus is covered by a set of fibres (arcuate fibres), which issue from the 

 anterior median fissure, turn upwards over the anterior pyramids to pass 

 directly into the corresponding hemisphere of the cerebellum, being 

 joined by the fibres of the direct cerebellar tract; the funiculus of 



n.c. 



FIG. 338. 



FIG. 339. 



FIG. SSS.-^ection of the medulla oblongata in the region of the superior pyramidal decussation; 

 <t.m.f., anterior median fissure; /.a., superficial arciform fibres emerering from the fissure; py., 

 pyramid; n.a.r., nuclei of arciform fibres; /.a., deep arciform becoming superficial; o., lower end 

 of olivary nucleus; n.L, nucleus lateralis; jf.r., formatio reticularis; /,a.2, arciform fibres proceeding 

 from the formatio reticularis; gr., substantia gelatinosa of Rolando; a.F., ascending root of fifth 

 nerve; nc., nucleus cuneatus; n.c'., external cuneats nucleus; n.g., nucleus gracilis; f.g., funiculus 

 gracilis; p.m./., posterior median fissure; c.c., central canal surrounded by gray matter, in which 

 are n.XL, nucleus of the spinal accessory, and n.XIL, nucleus of the hypoglossal; s.d.. superior 

 pyramidal decussation. (Modified from Schwalbe.) 



FIG. 339. Section of the medulla oblongata at about the middle of the olivary body. f.l.a., ante- 

 rior median fissure; n.ar., nucleus arciformis; p., pyramid; XII., bundle of hypoglossal nerve 

 emerging from the surface; at b, it is seen coursing between the pyramid and the olivary nucleus, o. ; 

 f.a.e., external arciform fibres; n.l , nucleus lateralis; a., arciform fibres passing towards restiform 

 body, partly through the substantia gelatiuosa, g., partly superficial to the ascending root of the 

 fifth nerve, a.F.; X., bundle of vagus root emerging; /.r., formatio reticularis; c.r., corpus resti- 

 forme, beginning to be formed, chiefly by arciform fibres, superficial and deep; n.c., nucleus cune- 

 atus; n.g., nucleus gracilis; ., attachment of the ligula; f.s., funiculus solitaries; n.X , n.X'., two 

 parts of the vagus nucleus; n.XIL, hypoglossal nucleus; n.t., nucleus of the funiculus teres; n.am., 

 nucleus ambigu us; r., raphe; A., continuation of the anterior column of cord; o', o", accessory 

 olivary nucleus; P.O., pedunculus olivae. (Modified from Schwalbe.) 



Eolando, and the funiculus cuneatns, although appearing to join them, 

 do not actually do so, except to a partial extent. 



