ADDENDUM ON THE PYRAMIDAL TRACTS 
By C. S. Sherrington 
The spinal degeneration resulting from ablation in the precentral gyrus of the 
above-mentioned ' hand '-area, discovers in the anthropoid cord the human feature of 
a perfectly large direct ventral (Ttircksbundel) as well as crossed pyramidal tract. 
The relative sizes of these tracts seem about the same as in man. 
The homolateral or uncrossed lateral division of the pyramidal tract is also well 
seen. The crossed pyramidal degeneration from the hand area lesion is clearly trace- 
able down to the lumbar region of the cord. In the lowest brachial segments there 
is obvious degeneration of fibres in the grey matter of the ventral horn of the crossed 
side. Some of the large nerve-cells there seem also degenerate. 
A lesion at the top of the gyrus precentralis gave no ventral pyramidal tract 
degeneration, and only a very slight uncrossed lateral pyramidal, although an exten- 
sive crossed lateral, that descends the whole length of the cord. 
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