

ANATOMICAL WD PHYSIOLOGICAL STUDIES ON 



\e we know, the radial breadth of the membrane increases 

 gradually from the basal to the apical turn. Table 5 (charts 4, 

 .">. and 6 shows how the breadth of the total and of each part 

 of thf membrane changes in successive turns from base to apex 

 according to age. At birth it is broadest in the beginning of the 

 middle turn (turn II) decreasing gradually towards the apex. 

 From three to twenty days the greatest breadth is usually found 



TABLE 4 



ige radial l<r<<i'lllt of the membrana tectoria and its thickness in radial-vertical 

 section. Averages of all four turns (charts 2 and S) 



Outer zone 

 between free 

 end of mem- 

 brane and 

 labium 



M 

 140 

 134 

 154 

 l.-,s 

 157 

 160 

 1 62 

 162 

 1(12 

 162 

 161 

 it;:; 

 162 

 163 

 1.2 

 1.0 

 1.0 



Inner zone 



labium 

 vestibulare 

 and inser- 

 tion of mem- 

 brane 



37 



94 

 105 

 123 

 126 

 124 

 129 

 128 

 131 

 132 

 131 

 129 

 131 

 132 

 : 3 . 6 

 : 1.0 

 : 1.0 



Total length 

 of mem- 

 brane 



M 



177 



228 

 259 

 281 

 283 

 284 

 291 

 290 

 293 

 294 

 292 

 292 

 293 

 295 

 1 : 1.7 

 : 1.0 

 : 1.0 



Ratios 

 inner and 

 outer zone 



3.78 

 1.43 

 1.44 

 1.28 

 1.25 

 1 . 29 

 1 . 26 

 1.27 

 1.24 

 1 . 23 

 1.23 

 1.26 

 1.24 

 1.23 



Thickness 

 membrane 



I'- 

 ll 

 32 

 32 

 27 

 25 

 28 

 38 

 34 

 35 

 36 

 32 

 38 

 35 

 34 

 2.8 

 1.4 

 0.9 



in turn III. but after this in turn IV. At the bottom of each 

 column are given the ratios of the radial breadth in each turn 

 between the several age limits. 



These -how that after twelve days there is but little change 

 111 the radial breadth of the entire membrane in any turn. 



examining the growth in each zone of the membrane 

 he several turns, we find that after three days the outer 

 """' "' tne membrane becomes at each age always broader 

 from base to apex. 



