{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,2]],"date-time":"2026-06-02T14:00:29Z","timestamp":1780408829067,"version":"3.54.1"},"reference-count":47,"publisher":"Public Library of Science (PLoS)","issue":"4","license":[{"start":{"date-parts":[[2021,4,16]],"date-time":"2021-04-16T00:00:00Z","timestamp":1618531200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100010665","name":"H2020 Marie Sk\u0142odowska-Curie Actions","doi-asserted-by":"publisher","award":["642662"],"award-info":[{"award-number":["642662"]}],"id":[{"id":"10.13039\/100010665","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>Wormian (intrasutural) bones are small, irregular bones, that are found in the cranial sutures of the skull. The occurrence of Wormian bones in human skulls has been well documented but few studies have detected the presence of such bones in domestic animals. Although some research has linked the presence of Wormian bones to bone pathology, its anatomical significance in healthy individuals is not known. To the best of our knowledge, no previous study has examined the biomechanical features of Wormian bone. This study uses microCT imaging of the parietal bone region to determine the frequency of occurrence of Wormian bones in horse skulls and, through 3-point bending tests, to calculate the mechanical differences that result from the presence of such bones. In addition, bone properties such as bone mineral density (BMD) and stiffness were measured and analysed to determine the influence of Wormian bone. Our findings on 54 specimens taken from 10 horses (ages ranging from 4 to 29 years) showed that Wormian bone was present in 70% of subjects and that its occurrence was unrelated to age or sex. 3-point bend tests revealed that the stiffness normalised by cross section area (P = 0.038) was lower in samples where Wormian bone was present. An idealised Finite Element simulation confirmed that the presence of Wormian bone reduced the maximum stress and strain, as well as their distribution throughout the sample. We consequently conclude that the presence of Wormian bones, which are confined to the calvaria, increase the compliance of the bone and reduce the likelihood of skull fracture. As all skull samples were collected from a local abattoir, ethical approval was not required for this work.<\/jats:p>","DOI":"10.1371\/journal.pone.0249451","type":"journal-article","created":{"date-parts":[[2021,4,16]],"date-time":"2021-04-16T17:50:26Z","timestamp":1618595426000},"page":"e0249451","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":7,"title":["The presence of Wormian bones increases the fracture resistance of equine cranial bone"],"prefix":"10.1371","volume":"16","author":[{"given":"Lilibeth A.","family":"Zambrano M.","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David","family":"Kilroy","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Arun","family":"Kumar","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael 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Kozerska","year":"2013","journal-title":"Folia Med Cracov"},{"key":"pone.0249451.ref007","first-page":"291","article-title":"Unusual presence of Wormian (sutural) bones in human skulls","volume":"74","author":"AA Khan","year":"2011","journal-title":"Folia Morphol (Warsz)"},{"key":"pone.0249451.ref008","doi-asserted-by":"crossref","first-page":"1681","DOI":"10.1002\/ajmg.a.33448","article-title":"Wormian bones in osteogenesis imperfecta: Correlation to clinical findings and genotype","volume":"152","author":"O Semler","year":"2010","journal-title":"Am J Med Genet Part A"},{"key":"pone.0249451.ref009","doi-asserted-by":"crossref","first-page":"35","DOI":"10.1007\/BF00361366","article-title":"Wormian bones in osteogenesis imperfecta and other disorders","volume":"8","author":"B Cremin","year":"1982","journal-title":"Skeletal Radiol"},{"key":"pone.0249451.ref010","doi-asserted-by":"crossref","first-page":"255","DOI":"10.1002\/ajpa.1330230313","article-title":"The etiology and genetics of 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Anat"},{"key":"pone.0249451.ref014","volume-title":"Veterinary Embryology","author":"TA McGeady","year":"2017","edition":"2"},{"key":"pone.0249451.ref015","first-page":"73","article-title":"The structure and development of cranial and facial sutures","volume":"90","author":"JJ Pritchard","year":"1956","journal-title":"J Anat"},{"key":"pone.0249451.ref016","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1002\/jmor.10104","article-title":"Biomechanics of the rostrum and the role of facial sutures","volume":"257","author":"Katherine L. Rafferty","year":"2003","journal-title":"Morphology"},{"key":"pone.0249451.ref017","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1098\/rspb.2008.0863","article-title":"Assessment of the role of sutures in a lizard skull: A computer modelling study","volume":"276","author":"M Moazen","year":"2009","journal-title":"Proc R Soc B Biol Sci"},{"key":"pone.0249451.ref018","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1098\/rsif.2013.0442","article-title":"Cranial sutures work collectively to distribute strain throughout the reptile skull","volume":"10","author":"N Curtis","year":"2013","journal-title":"J R Soc Interface"},{"key":"pone.0249451.ref019","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1002\/ajpa.1330860102","article-title":"Masticatory-stress hypotheses and the supraorbital region of primates","volume":"86","author":"WL Hylander","year":"1991","journal-title":"Am J Phys Anthropol"},{"key":"pone.0249451.ref020","doi-asserted-by":"crossref","first-page":"557","DOI":"10.1002\/ar.21133","article-title":"Allometry of masticatory loading parameters in mammals","volume":"293","author":"MJ Ravosa","year":"2010","journal-title":"Anat Rec (Hoboken)"},{"key":"pone.0249451.ref021","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1002\/(SICI)1096-8644(199702)102:2<203::AID-AJPA5>3.0.CO;2-Z","article-title":"In vivo bone strain patterns in the zygomatic arch of macaques and the significance of these patterns for functional interpretations of craniofacial form","volume":"102","author":"WL Hylander","year":"1997","journal-title":"Am J Phys Anthropol"},{"key":"pone.0249451.ref022","volume-title":"The anatomy of the domestic animals","author":"S Sisson","year":"1953","edition":"4"},{"key":"pone.0249451.ref023","volume-title":"Mechanical testing of bone and the bone-implant interface","author":"Y An","year":"2000","edition":"1"},{"key":"pone.0249451.ref024","doi-asserted-by":"crossref","first-page":"1048","DOI":"10.1016\/j.bone.2010.08.012","article-title":"Effects of three different preservation methods on the mechanical properties of human and bovine cortical bone","volume":"47","author":"U Stefan","year":"2010","journal-title":"Bone"},{"key":"pone.0249451.ref025","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1016\/j.jbiomech.2014.11.034","article-title":"Relationships between tissue composition and viscoelastic properties in human trabecular bone","volume":"48","author":"X Ojanen","year":"2015","journal-title":"J Biomech"},{"key":"pone.0249451.ref026","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1016\/j.mechrescom.2014.04.001","article-title":"Characterization and micromechanical modeling of the human cranial bone elastic properties","volume":"60","author":"J Rahmoun","year":"2014","journal-title":"Mech Res Commun"},{"key":"pone.0249451.ref027","doi-asserted-by":"crossref","first-page":"1180","DOI":"10.1016\/j.jbiomech.2013.10.060","article-title":"Geometrical and material parameters to assess the macroscopic mechanical behaviour of fresh cranial bone samples","volume":"47","author":"A Auperrin","year":"2014","journal-title":"J Biomech"},{"key":"pone.0249451.ref028","first-page":"1","article-title":"ASTM D 7250\/D 7250M Standard practice for determining sandwich beam flexural and shear stiffness","volume":"i","author":"ASTM International","year":"2009","journal-title":"Annu B ASTM Stand"},{"key":"pone.0249451.ref029","volume-title":"Mechanics of materials","author":"RC Hibbeler","year":"2011"},{"key":"pone.0249451.ref030","volume-title":"Mechanics of Materials","author":"JM Gere","year":"2004","edition":"6"},{"key":"pone.0249451.ref031","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1016\/j.clinbiomech.2007.08.024","article-title":"Mathematical relationships between bone density and mechanical properties: A literature review","volume":"23","author":"B Helgason","year":"2008","journal-title":"Clin Biomech"},{"key":"pone.0249451.ref032","doi-asserted-by":"crossref","first-page":"2129","DOI":"10.1016\/j.jbiomech.2009.05.030","article-title":"The mechanical properties of cranial bone: The effect of loading rate and cranial sampling position","volume":"13","author":"JA Motherway","year":"2009","journal-title":"Journal of Biomechancis"},{"key":"pone.0249451.ref033","doi-asserted-by":"crossref","first-page":"401","DOI":"10.1016\/j.compstruct.2016.06.040","article-title":"Sandwich structures with tunable damping properties: On the use of shape memory polymer as viscoelastic core","volume":"153","author":"P Butaud","year":"2016","journal-title":"Compos Struct"},{"key":"pone.0249451.ref034","doi-asserted-by":"crossref","first-page":"1876","DOI":"10.1177\/1077546314545527","article-title":"Vibration and damping characteristics of sandwich plates with viscoelastic core","volume":"22","author":"Z Huang","year":"2014","journal-title":"JVC\/Journal Vib Control"},{"key":"pone.0249451.ref035","unstructured":"Rikards R. Analysis of laminated structures. Course Lect. Riga, Latvia; 1999. http:\/\/ims.rtu.lv\/wp-content\/uploads\/sites\/86\/2017\/07\/R61.pdf"},{"key":"pone.0249451.ref036","doi-asserted-by":"crossref","first-page":"428","DOI":"10.1016\/j.diii.2013.01.001","article-title":"Wormian bones in a general paediatric population","volume":"94","author":"B. Marti","year":"2013","journal-title":"Diagnostic and Interventional Imaging"},{"key":"pone.0249451.ref037","first-page":"8.1","article-title":"Bone Mechanics","author":"TM Keaveny","year":"2004","journal-title":"Stand Handb Biomed Eng Des"},{"key":"pone.0249451.ref038","doi-asserted-by":"crossref","first-page":"313","DOI":"10.1016\/0021-9290(90)90059-C","article-title":"Mechanical properties of cranial sutures","volume":"23","author":"CR Jaslow","year":"1990","journal-title":"J Biomech"},{"key":"pone.0249451.ref039","doi-asserted-by":"crossref","first-page":"364","DOI":"10.1115\/1.1287160","article-title":"Infant skull and suture properties: measurements and implications for mechanisms of pediatric brain injury","volume":"122","author":"SS Margulies","year":"2000","journal-title":"J Biomech Eng"},{"key":"pone.0249451.ref040","doi-asserted-by":"crossref","first-page":"1222","DOI":"10.1089\/neu.2006.23.1222","article-title":"Material properties of human infant skull and suture at high rates","volume":"23","author":"B Coats","year":"2006","journal-title":"J Neurotrauma"},{"key":"pone.0249451.ref041","unstructured":"Auperrin A. Caracact\u00e9risation tissulaire pour la d\u00e9termination du comportement de l\u2019os cranien: essais m\u00e9caniques et imagerie m\u00e9dicale. Universit\u00e9 de Valenciennes et du Hainaut-Cambresis, Francais. 2009."},{"key":"pone.0249451.ref042","doi-asserted-by":"crossref","first-page":"912","DOI":"10.1016\/j.jbiomech.2012.12.016","article-title":"Characterization of the bending strength of craniofacial sutures","volume":"46","author":"A Maloul","year":"2013","journal-title":"J Biomech"},{"key":"pone.0249451.ref043","doi-asserted-by":"crossref","first-page":"1808","DOI":"10.12659\/MSM.892278","article-title":"Mechanical properties of cranial bones and sutures in 1\u20132-year-old infants","volume":"20","author":"Y Chen","year":"2014","journal-title":"Med Sci Monit"},{"key":"pone.0249451.ref044","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1016\/j.forsciint.2015.01.030","article-title":"Statistical analysis of biomechanical properties of the adult sagittal suture using a bending method in a Japanese forensic sample","volume":"249","author":"S Torimitsu","year":"2015","journal-title":"Forensic Sci Int"},{"key":"pone.0249451.ref045","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1016\/0021-9290(81)90166-4","article-title":"Bending properties and ash content of fetal cranial bone","volume":"14","author":"TJ Kriewall","year":"1981","journal-title":"J Biomech"},{"key":"pone.0249451.ref046","doi-asserted-by":"crossref","first-page":"9","DOI":"10.1016\/0021-9290(80)90003-2","article-title":"The elastic modulus of fetal cranial bone: A first step towards an understanding of the biomechanics of fetal head molding","volume":"13","author":"GK McPherson","year":"1980","journal-title":"J Biomech"},{"issue":"6","key":"pone.0249451.ref047","doi-asserted-by":"crossref","first-page":"e26490","DOI":"10.1371\/journal.pone.0026490","article-title":"Why do woodpeckers resist head impact injury: A biomechanical investigation","author":"L Wang","year":"2011","journal-title":"PLoS One"}],"container-title":["PLOS ONE"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0249451","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2021,4,16]],"date-time":"2021-04-16T17:51:20Z","timestamp":1618595480000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0249451"}},"subtitle":[],"editor":[{"given":"John Leicester","family":"Williams","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2021,4,16]]},"references-count":47,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2021,4,16]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0249451","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,4,16]]}}}