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Home / Equine Research Bank / Vet Res Commun / The use of the geometric morphometric method to illustrate s...
Veterinary research communications2020; 44(3-4); 137-145; doi: 10.1007/s11259-020-09779-8

The use of the geometric morphometric method to illustrate shape difference in the skulls of different-aged horses.

Abstract: The geometric morphometrics method (GMM) is a technique to study scale and shape relationships of structures using Cartesian geometric coordinates rather than linear, areal (of area), or volumetric variables. GMM has been of great value in many biological studies, but does not appear to have been used to examine equine skulls.In this exploratory study, twenty-nine normal equine heads of three different age groups:  16 years old (N = 10) were examined.Computed tomography (CT) bone window DICOM images were reconstructed into isosurfaces (3-dimensional contoured surfaces), onto which landmarks were added using Stratovan Checkpoint® software. Data from 29 landmarks were analysed using MorphoJ analysis, which applies a Procrustes fit, prior to reducing data dimensionality through principal component (PC) analysis. PCs with and without allometry were considered. Allometric shape described by PC1 accounted for 27% of variance. Loading pertaining to: the pterygoid process, bilaterally; caudal aspect of hard palate; tip of nasal bone; ethmoid sinuses, bilaterally; caudal aspect of the ventral conchal bulla, bilaterally and caudal aspect of the vomer bone suggest that these anatomical structures are predictive of age group. When allometric effects (shape variation explained by size) were removed, PC1 was unable to distinguish horses by age group. Allometric shape differences could distinguish the youngest versus the two older age groups. The potential applications of GMM in equine diagnostic imaging are wide ranging and include the investigation of changes in the equine skull with respect to genetics and characterisation of conformation-related diseases affecting the teeth, jaws and sinonasal compartments.
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Publication Date: 2020-07-23 PubMed ID: 32700122PubMed Central: PMC7568715DOI: 10.1007/s11259-020-09779-8Google Scholar: Lookup
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Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

The researchers conducted a study using the geometric morphometrics method (GMM) to understand the relationship between scale and shape in horse skulls of different ages.

Overview of the Geometric Morphometrics Method (GMM)

  • GMM is a technique used to study the relationship of scale and shape in biological structures.
  • The method’s distinct feature is its utilization of Cartesian geometric coordinates instead of linear, areal, or volumetric measures to assess structures.
  • Though it has proved beneficial in many biological examinations, GMM has seldomly been used to study horse skulls. This research aims to explore its use specifically in this situation.

Research Technique and Analysis

  • The examined sample consisted of twenty-nine horse heads falling under three different age groups: under 5 years old, between 6-15 years old and over 16 years old.
  • The researchers used Computed tomography (CT) bone window DICOM images and reconstructed them into isosurfaces or three-dimensional contoured surfaces. They added landmarks to the images using Stratovan Checkpoint® software.
  • The data from these 29 landmarks were analyzed using MorphoJ analysis. MorphoJ analysis uses a method called a Procrustes fit to analyze the data. It then reduces data dimensionality through a principal component (PC) analysis.

Results

  • Allometric shape variance, described by the first principal component, accounted for 27% of the total variance. Moreover, the researchers found that several anatomical structures influence the age prediction of the horse.
  • These structures include the pterygoid process, caudal aspect of the hard palate, tip of the nasal bone, ethmoid sinuses, caudal aspect of the ventral conchal bulla and caudal aspect of the vomer bone.
  • The study also found a significant distinction in allometric shape variance when comparing the youngest horses with the two older age groups.
  • When researchers removed allometric effects (shape variations explained by size), the first principal component was unable to correctly predict the age of the horses.

Potential Implications of the Study

  • The findings in this study suggest that the GMM has extensive potential applications in equine diagnostic imaging.
  • It could be used to investigate changes in the equine skull related to genetic factors and characterization of diseases associated with conformation affecting the teeth, jaws, and sinonasal compartments.

Cite This Article

APA
Liuti T, Dixon PM. (2020). The use of the geometric morphometric method to illustrate shape difference in the skulls of different-aged horses. Vet Res Commun, 44(3-4), 137-145. https://doi.org/10.1007/s11259-020-09779-8

Publication

Veterinary research communications
ISSN: 1573-7446
NlmUniqueID: 8100520
Country: Switzerland
Language: English
Volume: 44
Issue: 3-4
Pages: 137-145

Researcher Affiliations

Liuti, Tiziana
  • Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Midlothian, Scotland, EH25 9RG, UK. Tiziana.liuti@ed.ac.uk.
  • Division of Veterinary Clinical Studies Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Midlothian, Scotland, EH25 9RG, UK. Tiziana.liuti@ed.ac.uk.
Dixon, Padraic M
  • Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Midlothian, Scotland, EH25 9RG, UK.
  • Division of Veterinary Clinical Studies Royal (Dick) School of Veterinary Studies and the Roslin Institute, University of Edinburgh, Midlothian, Scotland, EH25 9RG, UK.

MeSH Terms

  • Age Factors
  • Animals
  • Female
  • Horses / anatomy & histology
  • Male
  • Skull / anatomy & histology
  • Veterinary Medicine

Conflict of Interest Statement

No conflict of Interest have been declared.

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Citations

This article has been cited 4 times.
  1. Salamanca-Carreño A, Parés-Casanova PM, Monroy-Ochoa NI, Vélez-Terranova M. Would the Cephalic Development in the Purebred Arabian Horse and Its Crosses Indicate a Paedomorphic Process?. Animals (Basel) 2022 Nov 16;12(22).
    doi: 10.3390/ani12223168pubmed: 36428393google scholar: lookup
  2. Piria M, Špelić I, Nikolić S, Bakiu R, Hamilton JS, Gardner JPA. The Influence of Aquaculture and a Natural Environmental Gradient on Shell Landmark Variation of the Mediterranean Mussel (Mytilus galloprovincialis Lamarck, 1819) From the Eastern Adriatic Sea. J Morphol 2025 Apr;286(4):e70043.
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  3. Rebrina F, Brigić A, Kasalo N, Skejo J. The pronotum shape of scelimenine grasshoppers (Orthoptera: Tetrigidae) likely represents an exaptation for heterogeneous niche colonization. Curr Zool 2025 Feb;71(1):89-98.
    doi: 10.1093/cz/zoae027pubmed: 39996261google scholar: lookup
  4. Marcotegui P, Islas-Ortega A, Cantatore D, Reshaid Y, Montes M, Barneche J, Martorelli S. Two methods for geometric morphometric analysis of trichodinids from killifishes. Parasitol Res 2024 Sep 25;123(9):332.
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