Table 1. Descriptive statistics and analysis of variants of the structures of the posterior cranial fossa taken from magnetic resonance venograms (mean, ±SD, mm)
*Significance of differences of the variants in the compared groups (ANOVA).
Variables
|
Males (n=20)
|
Females (n=32)
|
DC (n=10)
|
MC (n=16)
|
BC (n=26)
|
DEj
|
12.035
(3.024)
|
10.31
(2.41)
|
12.91
(3.68)
|
11.02
(2.38)
|
9.19
(2.41)
|
|
0.034*
|
0.051*
|
dST
|
11.94
(1.71)
|
10.69
(2.58)
|
11.59
(1.35)
|
10.58
(2.14)
|
10.06
(2.45)
|
|
0.706*
|
0.049*
|
dSS
|
9.66
(1.96)
|
10.56
(2.58)
|
10.23
(2.83)
|
10.17
(2.30)
|
10.02
(1.78)
|
|
0.151*
|
0.377*
|
pLL
|
114.04
(4.34)
|
105.6
(2.25)
|
107.86
(2.91)
|
110.4
(0.56)
|
112.6
(0.27)
|
|
0.0001*
|
0.002*
|
pAP
|
79.02
(4.73)
|
77.97
(5.12)
|
81.42
(2.59)
|
78.30
(4.47)
|
75.40
(4.16)
|
|
0.465*
|
<0.001*
|
DP
|
39.13
(2.25)
|
39.60
(5.32)
|
41.88
(5.61)
|
40.06
(3.91)
|
37.70
(3.43)
|
|
0.711*
|
0.024*
|
DA
|
39.71
(4.02)
|
37.12
(4.29)
|
39.72
(2.48)
|
38.24
(2.71)
|
34.67
(5.89)
|
|
0.038*
|
0.004*
|
Abbreviations: DEj, the distance between the external acoustic meatus and the transverse-sigmoid sinus junction; dST, the diameter of the transverse-sigmoid sinus junction; dSS, the diameter of the sigmoid sinus; pLL, the laterolateral diameter of the posterior cranial fossa; pAP, the anteroposterior diameter of the posterior cranial fossa; DP, the distance from the internal occipital protuberance to the posterior margin of the foramen magnum; DA, the distance from the dorsum sellae to the anterior margin of the foramen magnum.
Table 2. Correlation between the variables of the posterior cranial fossa measured on the magnetic resonance venograms, n=52, PC (2-tailed)
|
(1)
|
(2)
|
(3)
|
(4)
|
(5)
|
(6)
|
(7)
|
(8)
|
(9)
|
(1) LL
|
1
|
|
|
|
|
|
|
|
|
(2) AP
|
.373**
|
1
|
|
|
|
|
|
|
|
(3) DEj
|
0.086
|
.279*
|
1
|
|
|
|
|
|
|
(4) dSG
|
-0.124
|
0.193
|
0.030
|
1
|
|
|
|
|
|
(5) dSS
|
-0.150
|
-0.057
|
0.107
|
.372**
|
1
|
|
|
|
|
(6) pLL
|
.568**
|
0.104
|
0.176
|
-0.068
|
-0.128
|
1
|
|
|
|
(7) pAP
|
-0.171
|
.396**
|
0.004
|
.325*
|
0.030
|
-0.272
|
1
|
|
|
(8) DP
|
-0.221
|
0.071
|
.332*
|
0.039
|
-0.064
|
-0.531*
|
.305
|
1
|
|
(9) DA
|
0.271
|
-0.152
|
0.189
|
-0.112
|
-.320*
|
-0.230
|
.437**
|
.341*
|
1
|
**. Correlation is significant at the 0.01 level (2-tailed).
*. Correlation is significant at the 0.05 level (2-tailed).
|
Abbreviations: LL, the laterolateral diameter of the skull; AP, the anteroposterior diameter of the skull; DEj, the distance between the external acoustic meatus and the transverse-sigmoid sinus junction; dST, the diameter of the transverse-sigmoid sinus junction; dSS, the diameter of the sigmoid sinus; pLL, the laterolateral diameter of the posterior cranial fossa; pAP, the anteroposterior diameter of the posterior cranial fossa; DP, the distance from the internal occipital protuberance to the posterior margin of the foramen magnum; DA, the distance from the dorsum sellae to the anterior margin of the foramen magnum.
Table 3. Topographical characteristics of the transverse-sigmoid sinus junction in relation to the external acoustic meatus in brachycephalic (BC), dolichocephalic (DC), and mesocephalic (MC) phenotypical groups*
Variables
|
DC (n=10)
|
MC (n=16)
|
BC (n=26)
|
Type I (n=11)
|
7 (63%)
|
2 (18%)
|
2 (18%)
|
Type II (n=29)
|
3 (10.3%)
|
14 (48.27%)
|
12 (41.37%)
|
Type III (n=11)
|
0
|
2 (18%)
|
9 (82%)
|
*For visualization of the presented numerical data see Figure 4.
Abbreviations: DC, dolichocephalic; MC, mesocephalic; BC, brachycephalic; Type I, localization of the transverse-sigmoid sinus junction above the external acoustic meatus (as seen on the parasagittal MR venograms); Type II, localization of the transverse-sigmoid sinus junction at the same level with the external acoustic meatus; Type III, the transverse-sigmoid sinus junction lies below than the acoustic meatus (classification by Satoshi Tsutsumi et.al.).
Table 4. Descriptive statistics and analysis of variants of the structures of the posterior cranial fossa obtained from the cadaveric specimens of the skull base (mean, ±SD, mm)
Variables
|
Males (n=34)
|
Females (n=36)
|
DC (n=22)
|
MC (n=18)
|
BC (n=30)
|
Dp1
|
26.40
(3.64)
|
25.07
(3.43)
|
26.55
(4.91)
|
24.55
(2.85)
|
25.83
(2.55)
|
|
0.125*
|
0.308*
|
Dp2
|
37.55
(30.21)
|
35.34
(3.19)
|
38.40
(3.66)
|
37.09
(3.69)
|
36.33
(2.63)
|
|
0.005*
|
0.104*
|
dSG
|
12.42
(2.53)
|
12.14
(2.98)
|
12.11
(2.91)
|
13.60
(3.52)
|
11.58
(1.62)
|
|
0.679*
|
0.047*
|
Pp1
|
22.28
(3.97)
|
19.26
(3.01)
|
21.43
(3.64)
|
20.45
(2.67)
|
19.25
(4.24)
|
|
0.001*
|
0.071*
|
Pp2
|
34.10
(3.97)
|
32.14
(3.73)
|
34.72
(4.13)
|
31.65
(3.53)
|
29.15
(3.95)
|
|
0.041*
|
0.045*
|
Pp3
|
38.45
(6.10)
|
37.85
(6.64)
|
39.81
(6.69)
|
34.28
(5.57)
|
30.76
(5.92)
|
|
0.704*
|
0.031*
|
*Significance of differences of the variants in the compared groups (ANOVA).
Abbreviations: Dp1, the distance from the anterior margin of the sigmoid groove to the porus acusticus; Dp2, the distance from the posterior margin of the sigmoid groove to the porus acusticus; dSG, the diameter of the sigmoid groove; Pp1, the distance between the external acoustic meatus and the tip of the mastoid process; Pp2, the distance between the external acoustic meatus and the projection point of the posterior margin of the sigmoid groove; Pp3, the distance between the tip of the mastoid process and the projection point of the posterior margin of the sigmoid groove.
Table 5. Correlation between the variables of the posterior cranial fossa measured on the cadaveric specimens, n=70, PC (2-tailed).
|
(1)
|
(2)
|
(3)
|
(4)
|
(5)
|
(6)
|
(7)
|
(8)
|
(1) AP
|
1
|
|
|
|
|
|
|
|
(2) LL
|
.408**
|
1
|
|
|
|
|
|
|
(3) Dp1
|
.049
|
.032
|
1
|
|
|
|
|
|
(4) Dp2
|
.261*
|
-.032
|
.474**
|
1
|
|
|
|
|
(5) dSS
|
.189
|
-.030
|
-.325**
|
.320**
|
1
|
|
|
|
(6) Pp1
|
.085
|
-.372**
|
.137
|
.221
|
.050
|
1
|
|
|
(7) Pp2
|
.083
|
-.218*
|
.188
|
.412**
|
.186
|
.334**
|
1
|
|
(8) Pp3
|
-.038
|
-.009
|
.181
|
.259*
|
.125
|
.292*
|
.561**
|
1
|
**. Correlation is significant at the 0.01 level (2-tailed).
*. Correlation is significant at the 0.05 level (2-tailed).
|
Abbreviations: AP, the anteroposterior diameter of the skull; LL, the laterolateral diameter of the skull; Dp1, the distance from the anterior margin of the sigmoid groove to the porus acusticus; Dp2, distance from the posterior margin of the sigmoid groove to the porus acusticus; dSG, the diameter of the sigmoid groove; Pp1, the distance between the external acoustic meatus and the tip of the mastoid process; Pp2, the distance between the external acoustic meatus and the projection point of the posterior margin of the sigmoid groove; Pp3, the distance between the tip of the mastoid process and the projection point of the posterior margin of the sigmoid groove.