460 HALBERT L. DUNN 
TABLE 36 
Length of the spinal cord 
Formula: Spinal cord length (em.) = 10 crown-heel length (em.).467 — 4 
(144 cases) 
ROWS HE ENGre EPINAL CORD LENGTH CALCULATED DEAE 
SPINAL CORD | OBSERVED AND a pone 
Maxi: | Mini- LENGTH CALCULATED 
Range Mean main ant Mean MEANS 
cm. cm. cm. cm. cm. cm. cm. 
Oto 5 3.9 2.5 1.4 1.9 1.4 —0.5 4 
5 to 10 Coll 4.0 253 3.0 3.6 +0.6 9 
10 to 15 12.1 6:2 4.0 4.7 5.4 +0.7 20 
15 to 20 16.7 9.7 5.3 7.0 6.9 Oat 14 
20 to 25 Ded el Ole UD 8.7 8.6 —0.1 20 
25 to 30 26.9 10.7 8.5 9.75 9.6 —0.1 14 
30 to 35 32.6 isto3 9.0 10.6 10.9 +0.3 18 
35 to 40 37.1 16.5 9.5 12.2 11.8 —0.4 17 
40 to 45 42.2 14.0 11.0 12.4 12.8 +0.4 12 
45 to 50 48.2 14.8 Pe 7 1325 13.9 +0.4 8 
50 to 55 52.2 15.8 13.2 14.5 14.6 +0.1 8 
TABLE 37 
Calculated spinal cord length at 5-cm. intervals of crown-heel length 
INCREMENT IN EACH 
CROWN-HEEL LENGTH SPINAL CORD LENGTH 5-CM. INTERVAL 
RATIO TO NEW-BORN 
cm. cm. cm. per cent per cent 
5 2.2 15.5 
10 4.6 2.4 109.0 32.4 
15 6.4 1.8 39.2 45.0 
20 7.9 1.5 23.4 55.6 
25 9.2 ive 16.4 64.8 
30 10.4 12 13.0 73.3 
35 11.4 1.0 9.6 80.3 
40 12.4 1.0 8.2 87.3 
45 13.3 0.9 7.5 94.0 
50 14.2 0.9 6.5 100.0 
55 15.0 0.8 5.9 105.6 
6) percentage increments of volume curves (fig. 26) were determined for 5-cm. 
intervals; 7) percentage increments of linear curves (fig. 27) were calculated for 
age in fetal months; 8) percentage increments of linear curves (fig. 28) were 
determined for age in fetal months; 9) the various linear formulae of the respective 
absolute curves (table 43), and, 10) the volumetric formulae of the absolute 
volume curves (table 43) were compared. 
