A CASE OF HETEEOTOPIA OF THE WHITE MATTER IN THE 

 MEDULLA OBLONGATA. 



BY 



ALICE HAMILTON, M. D. 



Chicago, III. 



With 4 Text Figures. 



In the medulla of a child of six years, dying of acute poliencephalo- 

 myelitis, an aberrant nerve tract was found, lying in the substantia 

 reticularis grisea on the left side. The tract is visible to the naked 

 eye for the greater part of its extent and shows under the microscope 

 as a compact bundle of large medullated fibres, sharply marked off 

 from the surrounding gray matter. Beginning at the upper end we 

 find it emerging as a separate tract at the level of the lower end of the 

 fourth nucleus, lying between' the lemniscus medialis and the decussa- 

 tion of the brachium conjunetivum. It lies somewhat nearer the latter 

 than the former but seems to belong to the lemniscus rather than to the 

 brachium because the fibres are running longitudinally, as are the fibres 

 of the lemniscus, while the fibres of the brachium conjunetivum are 

 running across (Fig. 1). Going downward from this level the tract 

 begins to lie more dorsally, and after the ventral part of the brachium 

 conjunetivum has disappeared it lies in the substantia reticularis grisea 

 a little nearer the lemniscus medialis than the fasciculus longitudinalis 

 posterior, and nearer the mid-line than the outer edge (Figs. 2 and 3). 

 At the upper level of the nucleus nervi facialis it is situated a little 

 more mesially and ventrally, then it bends, runs transversely for a 

 short distance until it reaches the trapezoid body, where it again takes a 

 longitudinal course, lying now in between the fibres of the trapezoid, 

 not far from the nucleus nervi facialis (Fig. 4). It disappears abruptly 

 as if it had again bent upon itself, but the exact place of its termina- 

 tion could not be seen. It seems however most probable that it enters 

 the nucleus nervi facialis. 



To recapitulate: the tract arises from the lemniscus medialis, runs 

 down in the substantia reticularis grisea, and enters the nucleus nervi 

 facialis. 



Instances of heterotopia of white matter in the central nervous 



