Obstetric dimensions of the true pelvis in a Medieval ... - Anthropology

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a. dolicopellic (long oval)-the anteropos-
terior diameter exceeds the transverse di-
ameter.
b. mesatipellic (roundtthe anteroposte-
rior and transverse diameters are of equal
length, or the former exceeds the latter by
not more than 1 cm.
c. brachypellic (transverse ovaltthe
transverse diameter exceeds the anteropos-
terior diameter by more than 1 cm but less
than 3 cm.
d. platypellic (flatrthe transverse diam-
eter exceeds the anteroposterior diameter
by 3 cm or more.
In addition, certain obstetrically impor-
tant morphologic features, not associated
with measurement, were observed. These
included linearity of the pelvic sidewalls;
breadth, curvature, and inclination of the
sacrum; shape and breadth of the sacrosci-
atic notch; prominence of the ischial spines;
and curvature of the pubic rami.
Statistics
Age at death and dimensions of the pelvis
were described in terms of means, standard
deviations, and range values. In order to de-
termine whether a differential size effect
was operating within the sample, all pelvic
dimensions were correlated with femur
length. No correlations were significant at
P < 0.05 and, therefore, no further attempt
to statistically remove a body size effect was
made. Comparison to other archaeological
populations were made using Student's t
test.
RESULTS
General description
From the standpoint of shape, 58% of the
pelves were classifiable as brachypellic
(transverse oval), 28% mesatipellic (round),
11% dolichopellic (long oval), and 3% as
platypellic (flat). Shape of the midpelvis is
most often characterized by slightly conver-
gent sidewalls (indicated by greater inlet
than outlet transverse dimension) associ-
ated with well-rounded anterior and poste-
rior segments; well-curved neutrally in-
clined sacra; and well-rounded and wide
sacrosciatic notches associated with ischial
L. M. SIBLEY ET AL.
TABLE I. Obstetric dzmensions of the Kulubnarti Delves
Pelvic Inlet
Anteroposterior
Transverse
Oblique Left
Oblique Right
Pelvic Midplane
Anteroposterior
Transverse
Posterior Sagittal
Pelvic Outlet
Anteroposterior
Transverse
Subpubic Angle'
36
36
36
36
36
36
36
36
36
36
10.3
11.6
11.3
11.1
11.5
9.1
4.3
11.1
9.7
82.0
0.75
0.74
0.55
0.52
0.70
0.73
0.70
0.71
0.87
7.80
8.6-1 2.0
10.5-14.1
10.2-12.9
10.1-12.2
10.4-13.2
7.8-1 0.5
3.1-5.9
9.8-12.1
8.4-12.1
64.0-97.0
TABLE 2. Kulubnarti pelves compared with American
obstetric standard.s
%
US US Kulubnarti
Obstetric Dimensions Normal Contracted Contracted
Pelvic Inlet
Anteroposterior 10.5 40.0 33%
Transverse 13.5 42.0 67%
Oblique Left 12.5 - -
Oblique Right
Pelvic Midplane
12.5 - -
Anteroposterior 11.5 - -
Transverse (a) 10.5