Robert Bennett Bean. 403 
FoRAMEN OF MUNRO. 
The position of the foramen of Munro bears an interesting relation to 
the two ends of the curpus callosum and to the brain center, sexually and 
racially. Measurements are made on the brain axis, all points not on the 
axis being projected to it by lines perpendicular to the axis. The average 
of all measurements is represented in Table VIII in millimeters. In 
this table “Genu” and “Splenium” mean the anterior and posterior 
ends, respectively, of the corpus callosum. The “ Ratio” is the number 
preceding it divided by the length of the brain axis for that race and sex. 
The two hemispheres measure alike practically. A difference of one milli- 
meter in the numbers in the table is to be ignored. 
TABLE VIII. 
RELATIVE POSITIONS OF THE GENU, SPLENIUM, FORAMEN OF MUNRO, AND BRAIN 
CENTER. AVERAGES AND RATIOS. 
ar ghcas tans ls ee q 
aa! Ses 5 5 Fs ce HOS 3 
Gey WSO Ce GSE sous et Gl 
see er a 3) cele Bic ag ees ooo ne 
On & O oe © Se oo og es 9 
Caucasian male io... - 26 1550 18 107 750" 300) 44) 262 32° 1190 6s 
INGE TOM ALe! isrercie ele mele) - 22 Om Ge 95) 48) 28544 262s = 1905 6S 
Caticasian ftemalens ses zou bon i 05) 4292  ARIL * AXO) alts) all 
Negro female .......... 29) 186> 145 (90 43. 270) 43) 276, 29). 186. 156 
The splenium is further from the brain center in the Negro than in the 
Caucasian, and it is further posterior in the female Negro than in the 
male. The foramen of Munro is nearer the brain center in the Negro 
than in the Caucasian and it is nearest in the female Negro. The genu 
is nearer the center in the Negro, and nearest in the female Negro. The 
splenium is further removed from the foramen of Munro in the female 
Negro than in any of the others. The genu is nearer the foramen of 
Munro in the females than in the males, there being no racial difference 
in either sex here. The corpus callosum and the foramen of Munro are 
both placed further posterior in the female Negro, indicating that more 
brain substance lies anterior to these structures in the female Negro than 
in the others. This corresponds to the findings in relation to the position 
of the fissure of Rolando. There is less brain substance anteriorly in the 
female Negro, the apparent discrepancy being due to the fact that the 
frontal lobes of the female Negro are long and slender. The male Negro 
has an intermediate position between the female Negro and the Caucas- 
sian in regard to the location of the corpus callosum and the foramen 
of Munro. 
