Cranium asymmetry in a modern Greek population sample of known age and sex

Chovalopoulou, Maria‐Eleni; Papageorgopoulou, Christina

doi:10.1007/s00414-016-1430-4

Cited by 12 publications

(16 citation statements)

References 40 publications

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“…The current study shows that with respect to a midplane fitted to the shared landmarks (type 0 assessment) or to side landmarks for balancing the two sides (type 1 assessment), asymmetry of the studied human skulls is generally directional, which is consistent with the previous discoveries in the literature (e.g. [ 33 , 34 ]). In general, in the studied population, female skulls appear clearly more asymmetric than male skulls.…”

Section: Discussionsupporting

confidence: 88%

“…Studies of asymmetry of human skulls have initially used length and angle measurements and lately the Procrustes analysis of landmarks, see, e.g. [ 12 , 17 , 33 – 35 ]. The current study shows that with respect to a midplane fitted to the shared landmarks (type 0 assessment) or to side landmarks for balancing the two sides (type 1 assessment), asymmetry of the studied human skulls is generally directional, which is consistent with the previous discoveries in the literature (e.g.…”

Section: Discussionmentioning

confidence: 99%

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Assessments of bilateral asymmetry with application in human skull analysis

Hou

Fagan

2021

PLoS ONE

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As a common feature, bilateral symmetry of biological forms is ubiquitous, but in fact rarely exact. In a setting of analytic geometry, bilateral symmetry is defined with respect to a point, line or plane, and the well-known notions of fluctuating asymmetry, directional asymmetry and antisymmetry are recast. A meticulous scheme for asymmetry assessments is proposed and explicit solutions to them are derived. An investigation into observational errors of points representing the geometric structure of an object offers a baseline reference for asymmetry assessment of the object. The proposed assessments are applicable to individual, part or all point pairs at both individual and collective levels. The exact relationship between the developed treatments and the widely used Procrustes method in asymmetry assessment is examined. An application of the proposed assessments to a large collection of human skull data in the form of 3D landmark coordinates finds: (a) asymmetry of most skulls is not fluctuating, but directional if measured about a plane fitted to shared landmarks or side landmarks for balancing; (b) asymmetry becomes completely fluctuating if one side of a skull could be slightly rotated and translated with respect to the other side; (c) female skulls are more asymmetric than male skulls. The methodology developed in this study is rigorous and transparent, and lays an analytical base for investigation of structural symmetries and asymmetries in a wide range of biological and medical applications.

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Section: Discussionsupporting

confidence: 88%

Section: Discussionmentioning

confidence: 99%

Assessments of bilateral asymmetry with application in human skull analysis

Hou

Fagan

2021

PLoS ONE

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Section: Measures Of Asymmetrymentioning

confidence: 99%

“…Although relatively underutilized in DOHaD studies, measures of asymmetry may represent a promising approach to assessing the relationship between developmental stress and health in archeological populations (Chovalopoulou et al, 2017;Weisensee, 2013). A recent study of cranial asymmetry in a modern Greek population found no association between early developmental environments and age at death, as assessed through measures of fluctuating asymmetry (FA) in the cranium (Chovalopoulou et al, 2017). However, a study of a much larger historical Portuguese population by Weisensee (2013) found an association between FA and cause of death, with more severe FA observed in individuals known to have died from degenerative versus infectious diseases.…”

Section: Measures Of Asymmetrymentioning

confidence: 99%

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Examining developmental plasticity in the skeletal system through a sensitive developmental windows framework

McPherson

2021

American J Phys Anthropol

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Developmental plasticity facilitates energetically costly but potentially fitnessenhancing adjustments to phenotypic trajectories in response to environmental stressors, and thus may significantly impact patterns of growth, morbidity, and mortality over the life course. Ongoing research into epigenetics and developmental biology indicate that the timing of stress exposures is a key factor when assessing their impact on developmental processes. Specifically, stress experienced within sensitive developmental windows (SDWs), discrete developmental periods characterized by heightened energy requirements and rapid growth, may alter the pace and tempo of growth in ways that significantly influence phenotypic development over both the short and long term. In human skeletal biology, efforts to assess how developmental environments shape health outcomes over the life course could be enhanced by incorporating the SDW concept into existing methodological approaches. The goal of this article is to outline an interpretive framework for identifying and interpreting evidence of developmental stress in the skeletal system using the SDW concept. This framework provides guidance for the identification of elements most likely to capture evidence of stress most relevant to a study's core research questions, the interpretation of developmental stress exhibited by those elements, and the relationship of skeletal indicators of stress to the demographic patterning of morbidity and mortality.

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Childhood stress and developmental instability: Comparing microscopic enamel defects and cranial fluctuating asymmetry in a colonial Mexican sample

Moes

Willermet

Hunley

et al. 2022

American Journal of Biological Anthropology

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Objectives Recent tests of the relationship between enamel defects, an indicator of early life stress, and fluctuating asymmetry (FA), a measure of cumulative developmental instability, have produced equivocal results. This may be because they use methods that underestimate the number of defects. We reinvestigate this relationship using high‐resolution microscopy images of tooth surfaces. Further, we test the hypothesis that developmental stresses during the earliest period of tooth development have a greater impact on FA than stresses during subsequent periods. Materials and Methods The sample consists of 48 individuals from two colonial‐era cemeteries in Mexico City. Using one canine from each individual, we created photomontages using a 2D light microscope. Tooth crowns were divided into three developmental periods. Defects were identified as widely spaced perikymata using moving z‐scores. We compared defect presence, frequency, and timing to FA calculated from 11 landmarks using geometric morphometrics from 3D models of each cranium. Results Both the presence and frequency of enamel defects are significantly associated with an increase in FA. Contrary to our expectations, defects that formed in the latest developmental period (4–5.5 years) were uniquely associated with an increase in FA, relative to the other two periods. Discussion The presence and frequency of stress during childhood increases developmental instability. The time between 4 and 5.5 years may be a sensitive window of development in which disruptions to growth have a long‐lasting effect on developmental instability. Results indicate that research on developmental stress should consider the timing and frequency of stress events to more fully understand their impact on later life.

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Cranium asymmetry in a modern Greek population sample of known age and sex

Cited by 12 publications

References 40 publications

Assessments of bilateral asymmetry with application in human skull analysis

Assessments of bilateral asymmetry with application in human skull analysis

Examining developmental plasticity in the skeletal system through a sensitive developmental windows framework

Childhood stress and developmental instability: Comparing microscopic enamel defects and cranial fluctuating asymmetry in a colonial Mexican sample

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