3.3 Morphometrical analysis
3.3.1 Pathology: mesomelia
next sectionThe skull shows clear evidence of a reduction in size (fig. 9) that also affected other parts of the body.
The frontal arc (85 mm) is probably 25 mm smaller than the smallest measurements of female skulls in northern Europe. The sagittal arc (93 mm) is similarly 20 mm smaller than usual for small skulls (Brothwell, personal observations).
These features are very unlikely to indicate microcephaly, a condition which does not normally reduce facial dimensions, but in this case the palate length (30 mm) is 15 mm less than usual.
If we consider ratios of humerus to radius length and femur to tibia, then an arm in a European would normally have a ratio around 1.4: 1.0. In this case it is 2.2: 1.0. The normal ratio of a leg is about 1.2: 1.0; that of Zweeloo Woman is 1.6: 1.0. So the level of reduction in both forearms is considerable, but the length ratio difference in the lower leg is far less, and also shows side-to-side asymmetry (the right leg ratio is 1.28: 1.0).
In the case of congenital reduction in longitudinal segments of the limbs in some forms of mesomelia, forearm reduction may result in ratios of 1.8: 1.0 (personal radiographic observations), which are similar to the Zweeloo ratio. We conclude that the congenital disorder of mesomelia is a possible explanation.
|
Figure 9 Zweeloo Woman’s ‘exploded’ skull (a) and detail of the frontal bone (b) showing signs of a cut made by a short blade above the left orbit. |
3.3.2 Stature
Estimation of dimensions on the basis of the outer body surface of the Zweeloo body led to an estimated stature of 155 cm (allowing for head and foot damage). Our measurement coincides with that previously provided by Stoddard (1995), who arrived at an overall stature of about 152 cm.
It should be noted that in a sample of 4.995 British women (Board of Trade 1957), 2.438 (49%) were between 141 and 159 cm, so these are not to be viewed as dwarfed statures. Therefore, Zweeloo Woman could be classified as an example of mesomelia. Approximate dimensions of other body measurements obtained for Zweeloo Woman are presented in figure 10.
|
Figure 10 Estimated dimensions of Zweeloo Woman compared with a northern European sample. |
The overall length of the trunk of Zweeloo Woman appears to be close to the British average for 30-44 year olds (Board of Trade 1957). The leg length, however, seems to be shorter (with due allowance for the damaged feet). The interacromion width of the Zweeloo body may be above average, but the waist circumference appears to be slightly smaller than the modern European mean. However, neither difference is significant.
Table 1 Measured lengths of bones (in cm) of Zweeloo Woman | |||
|
Length* in cm |
Length in cm |
Mean | |
|
(RB, DPM) |
(DB) | ||
|
Right humerus |
26.3 |
26.6 |
26.45 |
|
Left humerus |
# |
# |
# |
|
Right radius |
12.1 |
12.5 |
12.3 |
|
Left radius |
11.8 |
12.04 |
12.1 |
|
Right ulna |
# |
# |
# |
|
Left ulna |
12.7 |
13 |
12.82 |
|
Right femur |
32.6 |
(35.5)** |
34.05 |
|
Left femur |
# |
# |
# |
|
Left tibia |
21 |
21.8 |
21.4 |
|
Right fibula |
21.6 |
# |
# |
|
Left fibula |
18.1 |
# |
# |
|
# Fractured bones for which measurement could not be performed | |||
|
* Lenghts defined in Brothwell (1981) | |||
|
** Estimated with curvature corrected | |||
The stature estimated on the basis of the bones of Zweeloo Woman ranges from 130 to 135 cm when the humerus, femur and tibia are included in the calculation, and from 137 cm to 141 cm when the tibia is excluded (Table 2).
Table 2 Stature of Zweeloo Woman estimated on the basis of the bones | ||||
|
Index* |
Minimum |
Maximum |
Mean |
Comparative data× |
|
Humero/radial |
46 |
47 |
46.5 |
76.6 ± 1.8 |
|
Femuro/humeral |
80.1 |
74.4 |
77.7 |
71.2 ± 1.3 |
|
Femuro/tibial |
65.2 |
62.1 |
62.9 |
81.6 ± 1.7 |
|
*Indexes after Martin (1928) | ||||
|
×Mean of 138 central European populations with a total of 14,730 individuals, after Siegmund (2010) | ||||
The Pearson method was considered the most appropriate among the estimation methods, since the employed reference series corresponds most closely to European populations in terms of body proportions (Siegmund 2010, 73-76) and Pearson considers all the long bones in the regression. In contrast, Trotter & Gleser (1952) consider only the tibia, and when the tibia is not available they use the femur. This calculation method would have led to distortions in the case of Zweeloo Woman due to the short length of the tibia and the curvature of the femur.
Comparison with a large dataset of an archaeological population from central Europe contemporary with Zweeloo Woman shows that she was significantly shorter than the mean (153.3 cm) of the female population of this period (Siegmund 2010, 83). With due allowance for the standard deviation and the interquartile range, 96% of the female population of this period ranged from 144.3 to 162.3 cm. Taking into account the bone shrinkage commonly found in bog bodies, the stature of Zweeloo Woman could be considered short, but within normal limits.
3.3.3 Body proportions
Besides the stature, the body proportions were also calculated according to Martin (1928, 1067) (Table 3) to enable us to evaluate the unusual proportions of Zweeloo Woman. The FHI and FTI are both significantly smaller than those of central European populations, which vary (Siegmund 2010, 62, 64). The HRI is extremely low due to the abnormal shortening of the radius.
Table 3 Body proportion estimation of Zweeloo Woman | |||
|
Stature estimation with tibia |
Stature in cm | ||
|
Stature estimation method |
Minimum |
Maximum |
Mean |
|
133.6 |
137.1 |
135.3 | |
|
Trotter/Gleser, white (1952) |
127.7 |
132.8 |
130.3 |
|
Trotter/Gleser, negro (1952) |
127.3 |
131.9 |
129.6 |
|
Mean of Pearson, Trotter/Gleser |
129.52 |
133.94 |
131.73 |
|
Stature estimation without tibia |
Stature in cm | ||
|
Stature estimation method |
Minimum |
Maximum |
Mean |
|
139.4 |
143 |
141.3 | |
|
Trotter/Gleser, white (1952) |
134.6 |
141.8 |
138.2 |
|
Trotter/Gleser, negro (1952) |
134.1 |
140.7 |
137.4 |
|
Mean of Pearson, Trotter/Gleser |
136 |
141.8 |
138.9 |
3.3.4 Body Mass Index
The Body Mass Index (BMI) of Zweeloo Woman was calculated on the basis of the estimated stature and the femur head diameter using the formula of Auerbach & Ruff (2004) [which is actually a mean of the formulas of Ruff et al. (1991), McHenry (1992) and Grine et al. (1995) combined with Pearson’s method]. The BMI value of Zweeloo Woman is normal in comparison with present-day data provided by the World Health Organisation (2006), according to which values from 18.50 to 24.99 fall within the normal weight range ( Table 4).
Table 4 Body Mass Index estimation of Zweeloo Woman | |||||||
|
Stature estimation |
Body Mass estimation (values in kilogram) | ||||||
|
after Pearson |
after Ruff et al 1991 |
after McHenry 1992 |
after Grine et al 1995 |
mean (after Auerbach and Ruff 2004) |
BMI | ||
|
without tibia |
min |
139,4 |
40,46 |
33,99 |
38,34 |
37,60 |
19,34 |
|
max |
143,0 |
40,46 |
33,99 |
38,34 |
37,60 |
18,39 | |
|
mean |
141,2 |
40,46 |
33,99 |
38,34 |
37,60 |
18,86 | |
|
with tibia |
min |
133,6 |
40,46 |
33,99 |
38,34 |
37,60 |
21,07 |
|
max |
137,1 |
40,46 |
33,99 |
38,34 |
37,60 |
20,01 | |
|
mean |
135,3 |
40,46 |
33,99 |
38,34 |
37,60 |
20,53 | |