126 Miss M. P. FitzGerald. The Lumbosacral-coccygeal [June 17, 







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Chart XIV. — Curves showing the Percentage Values of the Ventral and of the Dorsal 

 Horns in the Total Grey Substance. 



The total area of the grey substance in each cross-section of the cord is taken as 100. 

 The ordinates denote percentage value, the abscissae the length of the cord in centimetres 

 measured from the uppermost section of the first lumbar region. 



Percentage of ventral horns V, line, dot, and cross. 



Percentage of dorsal horns D, broken line and cross. 



The percentage of the ventral horns (V) (Chart XIV, Table XIV) to the 

 total grey substance in the cross -section of the cord increases to a very- 

 marked extent between the first lumbar and the upper portion of the fifth 

 lumbar region, where the maximum (76 per cent.) is reached. The absolute 

 rise is 19 per cent. The percentage decreases from the upper portion of the 

 fifth lumbar region to the end of the cord, the absolute fall to the third 

 coccygeal region amounting to ca. 36 per cent. 



Inversely, the percentage of the dorsal horns decreases from the first to 

 the fifth lumbar region, and increases from the latter region to the end of the 

 cord, the maximum (59 per cent.) being reached in the region of the third 

 coccygeal nerve. 



The rise in the percentage of the ventral horns is very rapid between the 

 lower portion of the second lumbar region and the upper portion of the 

 fourth. 



The fall in percentage is most marked between the fifth lumbar and the 

 first sacral region (middle portion), and occurs chiefly in the sixth lumbar. 

 It again becomes marked between the second and third coccygeal, and in the 

 latter region. 



