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Ilium growth study: applicability in sex and age diagnosis
C. Rissech, A. Malgosa*
Unitat d’Antropologia, Department Biologia animal, Biologia vegetal i Ecologia, Universitat Auto
`noma de Barcelona,
Campus de Bellaterra, 08193 Bellaterra-Cerdanyola del Valle
`s, Spain
Abstract
The use of coxal elements for age and sex diagnosis from the skeleton is the primary and most widespread way of bringing us
closer to the identity of dead individuals in archaeological and certain forensic scenarios. Diagnosis in sub-adults, especially in
fetus and infant age, is not clear; and further studies are needed. This work presents the analysis of the growth of six variables in
the ilium, from birth to 97 years of age, in order to evaluate its significance and its capacity for age and sex determination during
and after growth. The materials used were 327 specimens from four documented Western European collections. Growth curves
were calculated for the three classical variables of the ilium (width, length and index) and three new variables of the acetabulum
area (horizontal and vertical diameter of the ilium acetabular surface and the ilium acetabular index).
None of the curves showed a lineal growth, except those of the horizontal diameter of the ilium acetabular surface for the
male series. The ilium width has the most complicated growth and it is explained by a four-degree polynomial. All thevariables
studied can be useful for adult sex discrimination with the exception of the ilium width and ilium acetabular index. Furthermore,
the most useful variables for subadult and adult age estimation in archaeological samples, as well as in forensic samples, are the
absolute measurements (ilium length and width, horizontal and vertical diameter of the ilium acetabular surface); however, the
ilium width is the best variable, as this can be applied to all growth ages using both sexual series together up to 20 years of age.
#2004 Elsevier Ireland Ltd. All rights reserved.
Keywords: Innominate; Acetabular point; Polynomial regression
1. Introduction
Despite the importance of having a register of growth
values for all the different skeletal elements, which are used
as the reference in the study of past population, not much
information is available on the pre- and post-natal growth of
the coxal bone or its elements from osteological material.
There is also a general lack of studies based on documented
skeletal collections and published data drawn mainly from
archaeological series.
An added problem in this situation is that the studies do
not analyze all age ranges. This is due to the difficulty in
conducting morphometric analysis through all the stages of
coxal development, from non-fused to fused bones.
However, the use of the acetabular point as a point of
reference offering anatomical guarantee [1] overcomes this
inconvenience, and allows us with confidence to begin the
study of the coxal bone from birth to old age.
From this perspective, a cross-sectional study of the
elements of the coxal bone has been planned: use of docu-
mented series with bones from all ages and a continuous
analysis over the development of the bone. In a previous
work [2], we considered that the isquium bone is a good
element in helping us to analyze age, and its length is the best
means of doing so. Isquium length and measurements of the
acetabular surface can also be used for adult sex discrimi-
nation.
The ilium is an important element for sex diagnostics, as
well as for age estimation in the adult [3,4,5] but it has not
www.elsevier.com/locate/forsciint
Forensic Science International 147 (2005) 165–174
* Corresponding author. Tel.: +34 93 5811860;
fax: +34 93 5811321.
E-mail address: Assumpcio.Malgosa@uab.es (A. Malgosa).
0379-0738/$ – see front matter #2004 Elsevier Ireland Ltd. All rights reserved.
doi:10.1016/j.forsciint.2004.08.007
been analyzed from this perspective. The main purpose of
this study is to analyze the growth of several variables in the
ilium from a documented sample, from birth to old age.
2. Materials and methods
The material used in this work consists of coxal bones
from 327 individuals taken from four documented skeletal
series: the St. Bride’s collection, London; Esqueletos iden-
tificados, Coimbra; the Lisbon collection, Lisbon; and the
UAB collection, Barcelona. Details regarding age and sex
appear in Table 1.
The variables selected are those that are classical for the
ilium (width, length and index); additionally, we use three
new variables that describe the ilium acetabular surface of
the immature acetabulum. Measurements used were:
Ilium width (Fig. 1.1): distance between antero-superior
iliac spine and postero-superior iliac spine. [6] The tech-
nique used was that proposed by Genove
´s[7] in adults and
Fazekas and Kosa ([8], ilium length) in sub-adults.
Ilium length (Fig. 1.2): maximum distance between the
acetabular point and the most distant point on the iliac
cresta (crestal point, [6]). The crestal point in adults was
located by Genoves’s procedure [7] and by Fazekas and
Kosa ([8], ilium breadth) in sub-adults.
Ilium index: percentage ratio between ilium width and
length [6].
Horizontal diameter of the ilium acetabular area
(Fig. 2.1): distance between the two upper angles situated
directly on the acetabular rim [9].
Vertical diameter of the ilium acetabular area (Fig. 2.2):
the perpendicular line to the horizontal diameter from the
acetabular point [9].
Ilium acetabular index: percentage ratio between the
horizontal and vertical diameter of the acetabular area
[9].
To locate the acetabular point and the angles of the ilium
acetabular area, descriptions made by Rissech et al. [1] have
been taken into account.
Ilium width, length and index were measured in all
individuals from the four series; however, the measurements
of the juvenile acetabular surface were restricted to the
young non-fused iliums. Nevertheless, these acetabular
measurements have also been taken in the UAB collection,
which consists only of adult individuals, in order to experi-
ence the applicability of these variables to adults. After
analyzing laterality on all measurements, the left bone
was chosen; if it was damaged or pathologic, however,
the right bone was then measured.
2.1. Statistical analysis
Documented series containing juvenile remains are few
and not very large. In addition, they are not homogeneous in
number, age or sex composition. The series used in this study
do not elude this situation; therefore, the intervals of age for
C. Rissech, A. Malgosa/ Forensic Science International 147 (2005) 165–174166
Table 1
Distribution of specimens by sex, age and population
Age Sb Co Lb Gr Total
<, <, <, <, < ,
0–4 3 1 11 5 14 6
5–9 5 2444 11 8
10–14 1 1 2 11 2 4 5 16
15–19 1 2 11 13 6 6 18 21
20–25 5 4 11 8 5 12 21 24
26–30236456 1313
31–352331562 1210
36–455796961 2419
46–553555973 2017
56–65 11 4 5 1 16 5
66–7535 34 6 9
76–97 1 3 5 10 6 13
42 38 49 52 56 56 19 5 166 161
Sb, St Bride collection, London (18th to 19th); Co, collection of
Esqueletos Identificados of Coimbra (19th to 20th Century); Lb,
Lisbon collection (19th to 20th Century); UAB, collection of the
Universitat Auto
`noma de Barcelona.
Fig. 1. Non fused (a) and fused (b) coxal bone: ilium with (1) and
ilium length (2).
Fig. 2. Non-fused coxal bone: vertical diameter (2) and horizontal
diameter (1) of ischium acetabular surface.
each sexual series have to be wider—5 years for sub-adults.
Intervals for adults were 20 years, because their growth
should have been finished, but the apposition phenomenon
could occur.
All the series were used as a whole, but the ANOVA test
in the adults and a graphic lowess method in sub-adults were
previously applied to analyze their homogeneity (The lowess
method is an iterative locally weighted least-squares method
by which a curve is fit to a set of points).
In order to attain an initial approximation of sexual
dimorphism for any variables, Student’st-test and the
Mann–Whitney U-test were applied to each age group.
The results from younger groups should be used carefully,
because they are not homogenous, and growth rhythm is not
the same within and among groups. This calculation there-
fore allows us to have a perception about the existence of
dimorphism in these variables at different stages of life.
To analyze the growth of the two sexual series, poly-
nomial regression models were performed, because it can
be supposed that, in general, growth dynamics can be
described by an incremental continuous function. In general
terms, growth may be described by the lowest order poly-
nomial.
In order to ascribe age at death, the inverse relation of the
variables has been calculated by taking age as the dependent
variable. Polynomial regression was calculated for both
sexual series separately, for forensic use. Moreover, in the
variables with no sexual differences, regression was applied
to the whole data, both female and male, together. The
benefit in this latter case is the possibility of its application
on unknown remains, therefore having archaeological and
anthropological use.
To perform the statistical analysis, Windows SPSS/PC
(Release 7.5.2S) and SAS/UNIX system (Release 6.10) were
used.
3. Results
For each variable and sex, all the fitted curves on the
graphic representation of the young specimens by lowess
method show a very similar pattern (Fig. 3). Growth may
therefore be considered similar, and the specimens were
analyzed together as a single series.
With regard to the homogeneity test in adult bones, all
series can be analyzed together with the exception of the
ilium length (F= 3.286 p= 0.024
*
,F= 8.951 p= 0.000
*
).
The female Iberian series and the male UAB collection have
higher mean values for ilium length than the Britannic series.
Ilium length analysis in adult samples was therefore inde-
pendently conducted in Iberian and Britannic series.
For the sake of clarity, the variables will be related
individually.
3.1. Ilium width
Students’t-test applied to each interval of age (Table 2)
shows no significant differences in sexual dimorphism. In
fact, the anthropological references for this variable show a
contradiction, some studies show that male iliums were
wider than the corresponding female bone [10–12]; others
show the contrary, female iliums were wider than those of
males [5,7,13]. Actually, the dimorphism in this variable is
less marked [5,7,10,13,14].
The best growth model for ilium width was a fourth-
degree polynomial regression (Fig. 4). The coefficients have
significance in the two sexual series, and the F-values
indicate the significance of the functions. The explained
variability of the models is 97% in males and almost 96% in
females.
In the fitted curves (Fig. 4), a restrained growth is
observed before the growth spurt, from 5 to 10 years of
C. Rissech, A. Malgosa / Forensic Science International 147 (2005) 165–174 167
Fig. 3. Male ischium width (IW) by populations (PB), age ED. Collections from UAB (Gr), Lisbon (Lb), Coimbra (Co) and St Bride (Sb).
age; this slowness in growth is characteristic of the hori-
zontal variables [15]. The beginning of the growth spurt for
this coxal dimension is at shortly over 10 years of age in
females and at approximately 14 for males. The maximum
for male and female curves (approximately 20 years)
indicates the end of growth, but this seems to be earlier
in girls, although with our data it is not possible to be more
precise.
The conclusion is that ilium width is not useful for
sexual diagnostic, but it is interesting for the estimation
of the age at death for both forensic and archaeological
remains due to the lack of sexual differences. Ilium width
is useful up to the age of 20, for female as well as male
skeletons, before growth has terminated. In order to assess
age at death, the inverse relation between ilium width and
the age was calculated (Table 3). A third-degree polynomial
regression for the unisex (male and female together) and
male series and a first-degree polynomial in the female
series were selected as the most fitted models: the variability
explained is greater than 87%, reaching almost 96% in the
male series.
3.2. Ilium length
From 0 to 4 years of age, girls from our series have a
higher mean value than boys, but from the age of 5 boys
show higher mean values (Table 4). However, these differ-
ences are not significant until adult age in the two popula-
tional subgroups (the Iberian and Britannic series, Table 4),
though differences in the group of 15–19 are close to
statistical significance. In order to more precisely analyze
the age at which differences begin, a Student’st-test was
applied at different intervals. From 16 to 19 years, differ-
ences between sexes were significant (124.66 males and
118.32 females, p= 0.031
*
) indicating that the beginning of
sexual dimorphism in ilium length starts at 15–16 years of
age, as a consequence of the growth spurt.
The best growth model for the ilium length was a second-
degree polynomial regression in both sexual series (Fig. 5),
which explains 96% of variability in males and 93% in
females. These models are in agreement with the constant
rhythm of the rate of growth in longitudinal measurements
[15], and because of this the curves do not show the
C. Rissech, A. Malgosa / Forensic Science International 147 (2005) 165–174168
Table 2
Mean values of ilium width and sexual differences in each age group
Age Sex n¯
xDS tMean range Up
0–4<9 63.0000 13.2193 6.56 14.000 0.298
,5 70.4000 17.4299 9.20
5–9<10 93.9000 4.3830 8.90 34.000 0.633
,8 94.1250 10.8685 10.25
10–14 <5 110.8000 9.8082 10.50 32.500 0.823
,14 112.0000 14.5232 9.82
15–19 <18 140.5556 12.1084 0.624 0.537
,21 142.6190 7.6386
20–25 <17 149.0000 9.8932 0.223 0.825
,22 149.7273 10.2501
26–40 <30 153.5000 8.4067 1.439 0.155
,30 150.3333 8.6357
41–97 <49 154.7347 9.6280 1.118 0.267
,42 152.7381 7.3818
(Student’st-test or the Mann–Whitney U-test).
Fig. 4. Polynomial regression lines and equations corresponding to the male (IW1) and female (IW2) ilium width. Coefficient, coefficient of the
function. tand p
1
, signification of the coefficient. Fand p
2
, signification of the functions. R
2
, explained variability.
adolescent upturn. The male curve is less pronounced than
that of the female; therefore, sexual differences in ilium
length are due to the higher growth rate in males. This is also
a characteristic of the horizontal variables [16].
Using our data as a basis, ilium length can be used to
diagnose sex from 16 years of age. Regarding the estimation
of age at death, this variable can be useful for the osteolo-
gical remains of known sex and for individuals between 0
and 16 years of unknown sex. The inverse relation between
ilium length and age at death (Table 3) is a third-degree
polynomial regression for two sexual series. Furthermore,
due to the absence of sexual differences before 16, mixed
C. Rissech, A. Malgosa / Forensic Science International 147 (2005) 165–174 169
Table 3
Ilium width (IW), ilium length (IL), horizontal diameter (HDI) and vertical diameter (VDI) of the acetabular area in ilium inverse functions to
the estimation of age at death in archaeological (unisex series) and forensic remains (series by sex)
Variable Coefficient p
1
Fp
2
R
2
Ilium width
<–,IW 0.639609 0.0001
*
432.06380 0.0000
*
0.92971
IW
2
0.008672 0.0000
*
IW
3
2.820471.10
5
0.0000
*
Constant 14.586156 0.0044
*
<IW 0.703194 0.0006
*
337.09526 0.0000
*
0.9574
IW
2
0.009271 0.0000
*
IW
3
2.989249.10
5
0.0000
*
Constant 16.612568 0.0064
*
,IW 0.191364 0.0000
*
354.81014 0.0000
*
0.87433
Constant 9.785714 0.0000
*
Ilium length
<–,IL 0.678840 0.0006
*
245.000 0.0000
*
0.91778
IL
2
0.010835 0.0000
*
IL
3
4.16322234.10
5
0.0000
*
Constant 12.783241 0.0103
*
<IL 0.889464 0.0001
*
291.61544 0.0000
*
0.94696
IL
2
0.012834 0.0000
*
IL
3
4.59915554.10
5
0.0000
*
Constant 18.569358 0.0016
*
,IL 1.216573 0.0080
*
124.27097 0.0000
*
0.87966
IL
2
0.017736 0.0014
*
IL
3
6.77231396.10
5
0.0014
*
Constant 25.287821 0.0372
*
Horizontal diameter of the acetabular area of the ilium
<–,HDI 0.402291 0.0000
*
355.39275 0.0000
*
0.86810
Constant 7.706326 0.0000
*
<HDI 0.395501 0.0000
*
351.48413 0.0000
*
0.91895
Constant 7.669898 0.0000
*
,HDI 0.426182 0.0000
*
57.26560 0.0000
*
0.73168
Constant 8.300057 0.0009
*
Vertical diameter of the acetabular area of the ilium
<–,VDI 0.585407 0.0000
*
219.25280 0.0000
*
0.80238
Constant 9.335846 0.0000
*
<VDI 0.586540 0.0000
*
183.10507 0.0000
*
0.85922
Constant 9.430888 0.0000
*
,VDI 0.575968 0.0000
*
40.23625 0.0000
*
0.64651
Constant 8.972333 0.0033
*
p
1
, signification of the coefficient; Fand p
2
, signification of the function; R
2
, variability explained by the model.
series can be used to calculate a unisex juvenile model,
which is also a third-degree equation. The variability
expressed in these models is higher than 87%, reaching
almost 95% in male series.
3.3. Ilium index
The mean values of ilium index are always higher in
females than in males (Table 5). Between 5 and 14 years,
incremental values are so slight as to be almost nil in girls;
they completely diminish in boys. This stage coincides with
the growth spurt stage of ilium width, when this variable
slows down growth, and ilium length continues to grow.
Between 10–14 and 15–19, there is a considerable increment
of the index. This fact indicates the beginning of the growth
spurt for ilium width, which increases the ilium index.
Sexual differences are significant from 15 years of age.
We can also observe an increment in index values
between the 20–25 and 26–40 age group that cannot be
attributed to growth. This increase can be related to the
adults of the St. Bride series, which have the greatest mean
values for this variable; it has therefore to be related with the
total series composition, more than with a true growth.
The growth of the ilium index can be expressed by a first-
degree polynomial regression in both sexual series, but the
variability explained by the equations is low (20 and 27%),
indicating large dispersion of individual values. Dispersion
in index values is normal because it involves various factors
[7]. Due to the low information furnished by the models,
their graphic representation and the calculus of the inverse
relation between ilium and age at death, for age estimation,
has not been considered.
From these results, the ilium index is useful in sexual
discrimination only from 15 years of age until old age, but it
becomes useless for age estimation.
3.4. Horizontal diameter of the ilium acetabular surface
No significant differences between sexes has been found
in the young series (Table 6). The average for this variable is
higher in girls than in boys from 0 to 4 years, but is higher in
boys from 5 years. After 12, female values become stabilized
C. Rissech, A. Malgosa / Forensic Science International 147 (2005) 165–174170
Table 4
Mean values of ilium length and sexual differences in each age group
Age Sex n¯
xDS tMean rang Up
0–4<12 58.7500 13.9813 8.38 22.500 0.213
,6 63.1667 13.0448 11.75
5–9<11 85.8182 5.2881 10.68 36.500 0.545
,8 83.7500 9.2852 9.06
10–14 <5 102.4000 5.3198 12.90 25.500 0.306
,15 98.7333 12.5725 9.70
15–19 <18 122.8333 9.5993 1.800 0.080
,21 117.9324 7.3108
20–97 Iberian <80 130.2125 8.2932 7.015 0.000
*
,74 122.0541 6.0384
Britannic <30 126.6000 11.2483 4.883 0.000
*
,32 114.9688 7.1909
(Student’st-test or the Mann–Whitney U-test).
Fig. 5. Polynomial regression lines and equations corresponding to the male (IL1) and female (IL2) ilium length. Coefficient, coefficient of the
function. tand p
1
, signification of the coefficient. Fand p
2
, signification of the functions. R
2
, explained variability.
due to the fusion of the coxal elements, but growth continues
in boys until 16 years of age. Averages obtained for boys and
girls at these ages are very different and suggest that such
differences would be significant when female growth stops.
To corroborate this hypothesis, adult coxal bones from the
UAB collection were analyzed and significant differences
between sexes have been found (x<= 45.83, x,= 40,21,
p= 0.001
*
).
The growth of the horizontal diameter in the ilium
acetabular area of the male and female series can be
expressed by a first-degree (R
2
= 0.92) and second-degree
polynomial, respectively (R
2
= 0.80) (Fig. 6). The model for
girls’growth indicates a slight deceleration from the begin-
ning, while boys maintain a constant growth rate. This could
be related to a smaller size of the female acetabulum.
Despite the fact that the growth of the female horizontal
diameter follows a second-degree polynomial, the age eva-
luation equation for this variable (Table 3) is obtained from
first-degree formulas for each sexual and unisex series. The
expressed variability in these models is higher than 73% and
exceeded 91% in the male series.
3.5. Vertical diameter of the ilium acetabular area
There are no significant differences between sexes in our
data (Table 6). However, the mean values for variables in
girls are higher than in boys until 9 years of age. From 13, the
male mean becomes higher and increases in adult age, where
differences are significant. This fact is verified in the UAB
series (x<= 36.83, x,= 31.00, p= 0.001
*
).
The growth of the vertical diameter in the ilium acet-
abular area can be expressed by a third-degree polynomial
for boys (R
2
= 0.92) and a second-degree polynomial for
girls (R
2
= 0.79) (Fig. 7). The distance between the fitted
curves of the two sexual series is very low until growth
ceases in the female series. The masculine line of the vertical
diameter has an upturn at the end of its growth, which could
be identified with a pubertal growth spurt. However, this
upturn is located at the end of the curve when growth is
finishing and the acetabulum is fusing. More than an indica-
tion of the growth spurt, this upturn could be viewed as an
artifact of the sample.
In relation with age determination, first-degree form-
ulae for each sexual series and unisex series have been
obtained (Table 3). The expressed variability in these mo-
dels is higher than 64%, reaching almost 86% in the male
series.
3.6. Ilium acetabular index
The main characteristic of this variable is the lack of
sexual differences in both subadult (Table 6) and adult
individuals (UAB series, x<= 80.7, x,= 77.5, p= 0.426).
However, the main values have a tendency to diminish,
indicating that vertical diameter growth is faster than that
of the horizontal diameter.
The graph of individual values shows a great dispersion,
and it is very difficult to approximate the growth of this
variable to a polynomial equation. For the male series, the
third-degree polynomial was the most significant, but only
explains 39% of variability. In the female series, it was
impossible to establish an equation. In this sense, graphic
representation does not furnish additional information to the
analysis and is not considered. The ilium acetabular index is
C. Rissech, A. Malgosa / Forensic Science International 147 (2005) 165–174 171
Table 5
Mean values of ilium index and sexual differences in each age group
Age Sex n¯
xDS tMean range Up
0–4<8 109.0208 6.0177 6.63 17.000 0.724
,5 111.3330 3.6247 7.60
5–9<10 110.9052 6.2227 8.40 29.000 0.360
,8 112.3615 3.4682 10.88
10–14 <5 108.1181 6.1081 7.60 23.000 0.298
,14 112.7095 4.4448 10.86
15–19 <18 114.5058 6.3855 3.102 0.004
*
,21 121.1635 6.9246
20–25 <17 116.3930 7.0317 3.011 0.005
*
,21 123.7287 7.7969
26–40 <29 119.2885 7.0391 3.560 0.001
*
,30 126.1222 7.6789
41–97 <49 119.6481 7.0082 4.192 0.000
*
,42 125.9653 7.3476
(Student’st-test or the Mann–Whitney U-test).
therefore not a useful element for sexual discrimination or
for age estimation.
4. Discussion
The growth pattern of the variables of the ilium bone
shows a continuous increase and follows first- and second-
degree polynomials. However, ilium width is an exception
since it follows a fourth-degree polynomial and displays a
non-growth stage before the growth spurt. The constant in
the growth rhythm is characteristic of vertical variables:
while vertical variables show a regular growth, horizontal
variables show a non-growth stage before the growth spurt
[15].
In general, the curves have a good fit and there is not a
great deal of scatter, as evidenced by the consistently high
correlation and the significance of the functions and the
coefficients achieved in the models. The category of the
polynomial obtained for ilium width in this work coincides
with those of Majo
´[17]. However, our results for ilium
length and the horizontal diameter of the acetabular area do
not coincide with the scarce literature available [17,18,19],
in which polynomial functions with a higher degree were
found (data from the other measurements of juvenile acet-
abulum proposed in this study are not available from other
studies, and thus cannot be compared). As in the case of the
ischium bone [2], it is very difficult to fit our data for ilium
length and horizontal diameter to a third-, fourth- or fifth-
degree polynomial, as has been found in the above-men-
tioned studies. Nor, in this case, can we explain the differ-
ences as deriving from sample size or measurement
definition, because both are similar and comparable. Never-
theless, auxology studies show that longitudinal measure-
ments have a linear or parabolic behavior, and this is in
agreement with the growth pattern of the variables analyzed
in the present work. On the other hand, we must take into
account that the acetabular area grows fast, and measure-
ments cannot display the growth spurt, as the three bone
elements are fused early, before the age at which this growth
spurt occurs.
Ilium width is the only variable having an upturn in its
growth curve as an indication of growth-spurt onset. This
upturn occurs approximately after 14 years of age in males
and at 10 in females, and possibly nearer 15 in males and 11
in females, taking into account data from ilium length. But it
is not possible to determine exactly when the beginning of
the growth spurt takes place.
The ages of growth spurt found for the ilium in the
present study fall into the standard intervals of age for
pubertal growth spurt in the extant population: 10.5–17.5
years of age in males and 9.5–14.5 in females [20]. On the
other hand, the mean age of fusion for the acetabular
elements (acetabular maturation) are 16 in males and 12
in females, which also falls into the standard intervals for the
current population: 14–17 and 11–15 in males and females,
C. Rissech, A. Malgosa / Forensic Science International 147 (2005) 165–174172
Tab le 6
Mean values of the horizontal diameter, vertical diameter and index of the acetabular surface of the ilium, with sexual differences in each age group
Horizontal diameter of the ilium Vertical diameter of the ilium Index of the acetabular surface of the ilium
Age n¯
xDS Mean rank Upn
¯
xDS Mean rank Upn
¯
xDS Mean rank Up
0–4
<13 25.4615 5.7099 8.65 21.500 0.289 13 20.3846 5.2367 8.46 19.000 0.208 13 79.5157 7.2859 9.35 30.500 0.849
,5 28.8000 7.2250 11.70 5 23.2000 5.9330 12.20 5 80.3923 4.1032 9.90
5–9
<10 38.1000 4.0125 10.59 37.500 0.600 10 29.8000 2.0440 9.45 35.500 0.696 10 78.6937 6.7523 10.00 35.000 0.696
,8 37.6250 5.2627 9.19 8 29.2500 4.0620 8.94 8 77.8207 3.3906 8.88
10–12
<3 44.6667 5.0332 8.17 11.500 0.573 3 32.0000 2.0000 5.67 11.000 0.573 3 72.4242 10.8458 6.00 12.000 0.692
,10 42.3000 2.6687 6.65 10 32.8000 1.6865 7.40 10 77.7552 5.4231 7.30
13–16
<6 55.1667 3.4881 ––6 38.8333 2.5626 –––6 70.5509 5.3593 ––
,1 51.0000 1 31.000 1 60.7843
(Student’st-test or Mann–Whitney’sU-test).
respectively [21]. Both characteristics indicate no delay in
growth in our series. In general, it is possible to say that the
analyzed series do not show evidence for secular change in
the ilium in light of the analysis of their measurements.
There is no evidence of either malnutrition, or delay in
growth; the osseous maturation and adult size is therefore
similar to extant populations.
4.1. Sexual dimorphism
From our results, sexual differences in ilium measure-
ments are caused by the end of growth in females. The only
exception is ilium length, in which differences come from
the high growth rate in males in relation to female growth.
This different behavior in measurements related to the
presence or absence of restrained growth before the growth
spurt distinguishes between vertical and horizontal vari-
ables. Vertical variables have a more constant growth
[15], and sexual differences are due to the ceasing of female
growth [16]. In contrast, horizontal variables show a
restrained growth before the growth spurt [15] and sexual
differences are due to the higher rate of growth during the
growth spurt [16]. In this way, the length and width of the
ilium have a combination of behaviors, both horizontal and
vertical. Ilium length (theoretically a vertical variable) does
not show restrained growth before the growth spurt (char-
acteristic of vertical variables), but its dimorphism is based
on the higher rate of male growth (characteristic of a
horizontal variable); ilium width shows the inverse behavior.
It is possible to explain this mixed behavior in ilium length
and width by alluding to the oblique anatomical position of
the coxal bone and its measurements.
Ilium length, index and the horizontal and vertical dia-
meters of acetabular surface are useful variables for
adult sexual determination. Ilium length and index are
effective from 16 to 15 years of age, respectively, but
acetabular measurements can be used from 12. Our results
agree with those of current anthropological literature on
adult coxal bones [5,7,10,13]. Ilium index is less known,
although it is appreciated for sexual discrimination in
fetuses [4,8], it is not used in adult coxal bones. It is possible
that the coxal index was not used because of the difficulty
in finding acetabular point; however, our results agree
with those of Arsuaga [5] and allow us to affirm the utility
of the ilium index in sexual discrimination from 15 to old
age.
There are few works that analyze ilium growth from bone
remains [17,22] and these only analyze growth, but not
sexual differences, without crossing the limits of the coxal
bone fusion. However, some studies on radiographic mate-
rial have stated that female ilium length at birth was larger
than male [11,23]; after birth, discontinuous sexual differ-
ences were found until 8 years of age, where boys have
greater measurements. In our study, no significant differ-
ences have been found at these ages, but the major/minor
relation is the same.
C. Rissech, A. Malgosa / Forensic Science International 147 (2005) 165–174 173
Fig. 6. Polynomial regression lines and equations corresponding to the male (HDI 1) and female (HDI 2) horizontal diameter of ilium acetabular
surface. Coefficient, coefficient of the function. tand p
1
, signification of the coefficient. Fand p
2
, signification of the functions. R
2
, explained
variability.
Fig. 7. Polynomial regression lines and equations corresponding to the male (VDI 1) and female (VDI 2) vertical diameter of ilium acetabular
surface. Coefficient, coefficient of the function. tand p
1
, signification of the coefficient. Fand p
2
, signification of the functions. R
2
, explained
variability.
Also in radiographic material, [14] did not find significant
differences between 9 and 18, but he did find sexual differ-
ences in the direction of the growth of landmarks in the ilium
crest that form a circumference arc that is longer in females
than males. The distance between acetabular point to crestal
point is, then, shorter in females than males, although the
crestal point in females is located further back than in males
[7] and this agrees with the significant differences obtained in
the present study from 16 years of age.
On the other hand, in spite of the small number in our
samples and of the caution needed, the degree of discrimi-
nation obtained by the new acetabular measurements pro-
posed in this work is particularly noteworthy.
4.2. Age determination
It is possible to estimate the age at death of subadult
individuals by using absolute measurements of the ilium.
The application of the regression equation for ilium width
and length are of greatest use because they do not become
stable until 20 years in both sexual series. Measurements of
the acetabular area have the most reduced application time,
because the acetabular fusion occurs early in development;
horizontal and vertical diameters are applicable only before
12 in females and before 16 in males.
The formulae of regression calculated from recent Wes-
tern European populations allow us to predict the age of
young human remains with accuracy. In general, calculated
curves fit well with our mixed European series and corre-
spond with the behavior deduced from the adult bone and
other skeletal segments. These are the first formulae
obtained from the ilium to diagnose osseous age and sex
in Western European human remains taking into account that
they cross the limits of coxal fusion.
Acknowledgements
We are grateful to Canon John Oates, Dr L. Scheuer, Dr.
S. Black, Dr. E. Cunha, M
a
. Augusta Rocha, Professor
Almanc¸a, Mr Luis Lopes and Dr Grac¸a Ramalinho for
permitting access to the human skeletal collections.
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