{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T17:19:46Z","timestamp":1790356786092,"version":"4.1.0"},"reference-count":47,"publisher":"Springer Science and Business Media LLC","issue":"6","license":[{"start":{"date-parts":[[2023,9,13]],"date-time":"2023-09-13T00:00:00Z","timestamp":1694563200000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2023,9,13]],"date-time":"2023-09-13T00:00:00Z","timestamp":1694563200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100001794","name":"The University of Queensland","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100001794","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Int J Legal Med"],"published-print":{"date-parts":[[2023,11]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>Craniofacial superimposition requires the photographic registration of a skull at transparency to a photograph of an antemortem (AM) face so that anatomical concordance between the two can be assessed. When the camera vantage point of the AM photograph is exactly replicated for skull photography, the superimposition is a relatively straightforward process as the images are precisely comparable without complicating factors. In practice, however, focus distances are almost never exactly replicated because the focus distance for AM face photography is rarely known. Embedded differences in perspective, thereby, drive the images away from correspondence, raising questions as to how much difference can be tolerated and what image registration methods should be used. Recently, a\u2009\u00b1\u20091% mismatch in facial height has been posited as an acceptable upper tolerance limit to differential perspective, but this proposition is speculative and has not yet been confirmed by tests on real-life images. In addition, the impact of image registration methods, though critically relevant, has received comparatively little consideration. This paper provides the first in-depth review of these intertwined perspective\/registration matters and objective evaluation of tolerances by using real 2D photographic images and synthetic images generated from 3D CT data to demonstrate perspective impact on skull morphology. Taken together, the review confirms a\u2009\u2264\u20091% perspective difference in facial height to be a suitable criterion for craniofacial superimposition (at least as a starting point for method improvement), and that image registration should be point-based using a sellion\/nasion combination to minimize anatomical misalignment in the principal region-of-interest (the mid-face).<\/jats:p>","DOI":"10.1007\/s00414-023-03081-3","type":"journal-article","created":{"date-parts":[[2023,9,13]],"date-time":"2023-09-13T13:02:00Z","timestamp":1694610120000},"page":"1767-1776","update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Perspective distortion tolerances and skull-face registration in craniofacial superimposition: an analytical review"],"prefix":"10.1007","volume":"137","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4630-2162","authenticated-orcid":false,"given":"Sean S.","family":"Healy","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8696-3809","authenticated-orcid":false,"given":"Carl N.","family":"Stephan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2023,9,13]]},"reference":[{"key":"3081_CR1","doi-asserted-by":"publisher","first-page":"189","DOI":"10.1007\/BF02114614","volume":"80","author":"R Helmer","year":"1977","unstructured":"Helmer R, Gruner O (1977) Sch\u00e4delidentifizierung durch Superprojektion nach dem Verfahren der elektronischen Bildmischung, modifiziert zum Trickbild-Differenz-Verfahren. Z Rechtsmed 80:189\u2013190. https:\/\/doi.org\/10.1007\/BF02114614","journal-title":"Z Rechtsmed"},{"key":"3081_CR2","first-page":"75","volume":"184","author":"R Helmer","year":"1989","unstructured":"Helmer R, Rohricht S, Petersen D, Moer F (1989) Plastische Gesichtsrekonstruktion als Moglichkeit der Identifizierung unbekannter Schadel (I). Archiv Kriminol 184:75\u201383","journal-title":"Archiv Kriminol"},{"key":"3081_CR3","doi-asserted-by":"publisher","first-page":"177","DOI":"10.1080\/00085030.1989.10757432","volume":"22","author":"RP Helmer","year":"1989","unstructured":"Helmer RP, Schimmler JB, Rieger J (1989) On the conclusiveness of skull identification via the video superimposition technique. J Can Soc Forensic Sci 22:177\u2013194. https:\/\/doi.org\/10.1080\/00085030.1989.10757432","journal-title":"J Can Soc Forensic Sci"},{"key":"3081_CR4","doi-asserted-by":"publisher","unstructured":"Stephan CN, Claes P (2016) Craniofacial identification: techniques of facial approximation and craniofacial superimposition. In: Blau S, Ubelaker DH, eds. Handbook of forensic anthropology and archaeology. 2nd ed. Left Coast Press Walnut Creek. 402-15.\u00a0https:\/\/doi.org\/10.4324\/9781315528939","DOI":"10.4324\/9781315528939"},{"key":"3081_CR5","first-page":"103","volume":"22","author":"KA Brown","year":"1993","unstructured":"Brown KA (1993) The Truro murders in retrospect: a historical review of the identification of the victims. Ann Acad Med Singap 22:103\u2013106","journal-title":"Ann Acad Med Singap"},{"key":"3081_CR6","first-page":"151","volume-title":"Craniofacial identification in forensic medicine","author":"JA Taylor","year":"1998","unstructured":"Taylor JA, Brown KA (1998) Superimposition techniques. In: Clement JG, Ranson DL (eds) Craniofacial identification in forensic medicine. Hodder Arnold, London, pp 151\u201364"},{"key":"3081_CR7","doi-asserted-by":"publisher","first-page":"238","DOI":"10.1017\/CBO9781139049566.019","volume-title":"Craniofacial identification","author":"M Yoshino","year":"2012","unstructured":"Yoshino M (2012) Craniofacial superimposition. In: Wilkinson CM, Rynn C (eds) Craniofacial identification. Cambridge University Press, Cambridge, pp 238\u201353. https:\/\/doi.org\/10.1017\/CBO9781139049566.019"},{"key":"3081_CR8","doi-asserted-by":"publisher","first-page":"1412","DOI":"10.1111\/1556-4029.12842","volume":"60","author":"DH Ubelaker","year":"2015","unstructured":"Ubelaker DH (2015) Craniofacial superimposition: historical review and current issues. J Forensic Sci 60:1412\u20131419. https:\/\/doi.org\/10.1111\/1556-4029.12842","journal-title":"J Forensic Sci"},{"key":"3081_CR9","doi-asserted-by":"publisher","unstructured":"Sauer NJ, Michael AR, Fenton TW (2012) Human identification using skull-photo superimposition and forensic image comparison. In: Dirkmaat D, ed. A companion to forensic anthropology. Wiley-Blackwell West Sussex. 435.\u00a0https:\/\/doi.org\/10.1002\/9781118255377.ch21","DOI":"10.1002\/9781118255377.ch21"},{"key":"3081_CR10","unstructured":"Snow CC (1976) A video technique for skull-face superimposition. 28th Annual Meeting of the American Academy of Forensic Sciences Washington, D.C."},{"key":"3081_CR11","unstructured":"Lan Y, Cai D (1993) Technical advances in skull-to-photo superimposition. In: \u0130\u015fcan MY, Helmer RP, eds. Forensic Analysis of the Skull. Wiley-Liss New York. pp 119\u201329"},{"key":"3081_CR12","doi-asserted-by":"publisher","first-page":"695","DOI":"10.1520\/jfs14538j","volume":"44","author":"D Austin","year":"1999","unstructured":"Austin D (1999) Video superimposition at the C.A. Pound laboratory 1987 to 1992. J Forensic Sci 44:695\u2013699. https:\/\/doi.org\/10.1520\/jfs14538j","journal-title":"J Forensic Sci"},{"key":"3081_CR13","first-page":"57","volume":"1","author":"KA Brown","year":"1983","unstructured":"Brown KA (1983) Developments in cranio-facial superimposition for identification. J Forensic Odontostomatol 1:57\u201364","journal-title":"J Forensic Odontostomatol"},{"key":"3081_CR14","doi-asserted-by":"publisher","first-page":"198.e1","DOI":"10.1016\/j.forsciint.2011.09.008","volume":"216","author":"GM Gordon","year":"2012","unstructured":"Gordon GM, Steyn M (2012) An investigation into the accuracy and reliability of skull-photo superimposition in a South African sample. Forensic Sci Int 216:198.e1-e6. https:\/\/doi.org\/10.1016\/j.forsciint.2011.09.008","journal-title":"Forensic Sci Int"},{"key":"3081_CR15","volume-title":"Medico-legal aspects of the Ruxton case","author":"J Glaister","year":"1937","unstructured":"Glaister J, Brash JC (1937) Medico-legal aspects of the Ruxton case. William Wood and Co., Baltimore"},{"key":"3081_CR16","doi-asserted-by":"publisher","first-page":"496","DOI":"10.1016\/j.forsciint.2015.05.030","volume":"257","author":"O Ib\u00e1\u00f1ez","year":"2015","unstructured":"Ib\u00e1\u00f1ez O, Vicente R, Navega DS et al (2015) Study on the performance of different craniofacial superimposition approaches (I). Forensic Sci Int 257:496\u2013503. https:\/\/doi.org\/10.1016\/j.forsciint.2015.05.030","journal-title":"Forensic Sci Int"},{"key":"3081_CR17","doi-asserted-by":"publisher","first-page":"34","DOI":"10.1111\/j.1556-4029.2007.00624.x","volume":"53","author":"TW Fenton","year":"2008","unstructured":"Fenton TW, Heard AN, Sauer NJ (2008) Skull-photo superimposition and border deaths: identification through exclusion and the failure to exclude. J Forensic Sci 53:34\u201340. https:\/\/doi.org\/10.1111\/j.1556-4029.2007.00624.x","journal-title":"J Forensic Sci"},{"key":"3081_CR18","doi-asserted-by":"publisher","first-page":"271","DOI":"10.1016\/j.fsisyn.2019.10.002","volume":"1","author":"DH Ubelaker","year":"2019","unstructured":"Ubelaker DH, Wu Y, Cordero QR (2019) Craniofacial photographic superimposition: new developments. Forensic Sci Int: Synergy 1:271\u2013274. https:\/\/doi.org\/10.1016\/j.fsisyn.2019.10.002","journal-title":"Forensic Sci Int: Synergy"},{"key":"3081_CR19","doi-asserted-by":"publisher","first-page":"1481","DOI":"10.1109\/TIFS.2018.2791434","volume":"13","author":"C Campomanes-\u00c1lvarez","year":"2018","unstructured":"Campomanes-\u00c1lvarez C, Martos-Fern\u00e1ndez R, Wilkinson C, Ib\u00e1\u00f1ez O, Cord\u00f3n O (2018) Modeling skull-face anatomical\/morphological correspondence for craniofacial superimposition-based identification. IEEE Trans Inf Forensics Secur 13:1481\u20131494. https:\/\/doi.org\/10.1109\/TIFS.2018.2791434","journal-title":"IEEE Trans Inf Forensics Secur"},{"key":"3081_CR20","doi-asserted-by":"publisher","first-page":"1697","DOI":"10.1007\/s00414-022-02871-5","volume":"136","author":"CN Stephan","year":"2022","unstructured":"Stephan CN, Healy S, Bultitude H, Glen C (2022) Craniofacial superimposition: a review of focus distance estimation methods and an extension to profile view photographs. Int J Legal Med 136:1697\u2013716. https:\/\/doi.org\/10.1007\/s00414-022-02871-5","journal-title":"Int J Legal Med"},{"key":"3081_CR21","doi-asserted-by":"publisher","first-page":"850","DOI":"10.1111\/1556-4029.13353","volume":"62","author":"CN Stephan","year":"2017","unstructured":"Stephan CN (2017) Estimating the skull-to-camera distance from facial photographs for craniofacial superimposition. J Forensic Sci 62:850\u2013860. https:\/\/doi.org\/10.1111\/1556-4029.13353","journal-title":"J Forensic Sci"},{"key":"3081_CR22","doi-asserted-by":"publisher","first-page":"100238","DOI":"10.1016\/j.fsir.2021.100238","volume":"4","author":"CN Stephan","year":"2021","unstructured":"Stephan CN, Armstrong B (2021) Scientific estimation of the subject-to-camera distance from facial photographs for craniofacial superimposition. Forensic Sci Int Rep 4:100238. https:\/\/doi.org\/10.1016\/j.fsir.2021.100238","journal-title":"Forensic Sci Int Rep"},{"key":"3081_CR23","doi-asserted-by":"publisher","first-page":"5","DOI":"10.1111\/1556-4029.12856","volume":"61","author":"D Gaudio","year":"2016","unstructured":"Gaudio D, Olivieri L, De Angelis D, Poppa P, Galassi A, Cattaneo C (2016) Reliability of craniofacial superimposition using three-dimension skull model. J Forensic Sci 61:5\u201311. https:\/\/doi.org\/10.1111\/1556-4029.12856","journal-title":"J Forensic Sci"},{"key":"3081_CR24","doi-asserted-by":"publisher","DOI":"10.1515\/9780804794886","author":"A Rosenblatt","year":"2015","unstructured":"Rosenblatt A (2015) Digging for the disappeared. Stanford University Press Stanford. https:\/\/doi.org\/10.1515\/9780804794886","journal-title":"Stanford University Press Stanford"},{"key":"3081_CR25","unstructured":"Marshall D (2006) Killing for pleasure. Random House Sydney"},{"key":"3081_CR26","unstructured":"Pudney J (2006) The bodies in the barrels murders. John Blake Great Britain"},{"key":"3081_CR27","doi-asserted-by":"publisher","first-page":"267","DOI":"10.1016\/j.legalmed.2015.02.001","volume":"17","author":"MI Huete","year":"2015","unstructured":"Huete MI, Ibanez O, Wilkinson C, Kahana T (2015) Past, present, and future of craniofacial superimposition: literature and international surveys. Leg Med (Tokyo) 17:267\u2013278. https:\/\/doi.org\/10.1016\/j.legalmed.2015.02.001","journal-title":"Leg Med (Tokyo)"},{"key":"3081_CR28","doi-asserted-by":"publisher","unstructured":"Damas S, Cord\u00f3n O, Ib\u00e1\u00f1ez O (2020) Handbook on craniofacial superimposition. 1st 2020. ed. Springer International Publishing Cham, Switzerland.\u00a0https:\/\/doi.org\/10.1007\/978-3-319-11137-7","DOI":"10.1007\/978-3-319-11137-7"},{"key":"3081_CR29","doi-asserted-by":"publisher","first-page":"446","DOI":"10.1520\/jfs13615j","volume":"39","author":"D Austin-Smith","year":"1994","unstructured":"Austin-Smith D, Maples WR (1994) The reliability of skull\/photograph superimposition in individual identification. J Forensic Sci 39:446\u2013455. https:\/\/doi.org\/10.1520\/jfs13615j","journal-title":"J Forensic Sci"},{"key":"3081_CR30","doi-asserted-by":"publisher","first-page":"59","DOI":"10.1016\/j.legalmed.2016.09.009","volume":"23","author":"O Ib\u00e1\u00f1ez","year":"2016","unstructured":"Ib\u00e1\u00f1ez O, Valsecchi A, Cavalli F et al (2016) Study on the criteria for assessing skull-face correspondence in craniofacial superimposition. Leg Med (Tokyo) 23:59\u201370. https:\/\/doi.org\/10.1016\/j.legalmed.2016.09.009","journal-title":"Leg Med (Tokyo)"},{"key":"3081_CR31","doi-asserted-by":"publisher","first-page":"504","DOI":"10.1016\/j.forsciint.2015.07.045","volume":"257","author":"S Damas","year":"2015","unstructured":"Damas S, Wilkinson C, Kahana T et al (2015) Study on the performance of different craniofacial superimposition approaches (II): best practices proposal. Forensic Sci Int 257:504\u2013508. https:\/\/doi.org\/10.1016\/j.forsciint.2015.07.045","journal-title":"Forensic Sci Int"},{"key":"3081_CR32","doi-asserted-by":"publisher","first-page":"379","DOI":"10.1007\/s00414-022-02931-w","volume":"137","author":"PT Jayaprakash","year":"2023","unstructured":"Jayaprakash PT (2023) Skull-photograph superimposition: elucidating and resolving misinterpretations pertaining to methods and reliability. Int J Legal Med 137:379\u2013381. https:\/\/doi.org\/10.1007\/s00414-022-02931-w","journal-title":"Int J Legal Med"},{"key":"3081_CR33","doi-asserted-by":"publisher","first-page":"110","DOI":"10.1016\/j.forsciint.2014.10.043","volume":"246","author":"PT Jayaprakash","year":"2015","unstructured":"Jayaprakash PT (2015) Conceptual transitions in methods of skull-photo superimposition that impact the reliability of identification: a review. Forensic Sci Int 246:110\u2013121. https:\/\/doi.org\/10.1016\/j.forsciint.2014.10.043","journal-title":"Forensic Sci Int"},{"key":"3081_CR34","unstructured":"Sekharan PC (1993) Positioning the skull for superimposition. In: \u0130\u015fcan MY, Helmer RP, eds. Forensic Analysis of the Skull. Wiley-Liss New York. pp 105\u201318"},{"key":"3081_CR35","first-page":"232","volume":"1","author":"PC Sekharan","year":"1973","unstructured":"Sekharan PC (1973) A scientific method for positioning of the skull for photography in superimposition studies. J police sci adm 1:232\u2013240","journal-title":"J police sci adm"},{"key":"3081_CR36","doi-asserted-by":"publisher","first-page":"118457","DOI":"10.1016\/j.eswa.2022.118457","volume":"210","author":"E Bermejo","year":"2022","unstructured":"Bermejo E, Fernandez-Blanco E, Valsecchi A, Mesejo P, Ib\u00e1\u00f1ez O, Imaizumi K (2022) FacialSCDnet: a deep learning approach for the estimation of subject-to-camera distance in facial photographs. Expert Syst Appl 210:118457. https:\/\/doi.org\/10.1016\/j.eswa.2022.118457","journal-title":"Expert Syst Appl"},{"key":"3081_CR37","doi-asserted-by":"publisher","first-page":"225","DOI":"10.1016\/0379-0738(89)90215-6","volume":"41","author":"GJR Maat","year":"1989","unstructured":"Maat GJR (1989) The positioning and magnification of faces and skulls for photographic superimposition. Forensic Sci Int 41:225\u2013235. https:\/\/doi.org\/10.1016\/0379-0738(89)90215-6","journal-title":"Forensic Sci Int"},{"key":"3081_CR38","unstructured":"Titlbach Z. (1970) Beitrage zur Bewertung der Superprojektionsmethode zur Identifizierung unbekannter Skelettfunde. Kriminalistik und forensische Wissenschaften. German Publisher of Sciences Berlin. pp 179\u201390"},{"key":"3081_CR39","doi-asserted-by":"publisher","first-page":"520.e1","DOI":"10.1016\/j.forsciint.2015.09.009","volume":"257","author":"CN Stephan","year":"2015","unstructured":"Stephan CN (2015) Perspective distortion in craniofacial superimposition: logarithmic decay curves mapped mathematically and by practical experiment. Forensic Sci Int 257:520.e1-e8. https:\/\/doi.org\/10.1016\/j.forsciint.2015.09.009","journal-title":"Forensic Sci Int"},{"key":"3081_CR40","volume-title":"Focus distance estimation from photographed faces: a test of PerspectiveX using 1,709 frontal and profile photographs from DSLR and smartphone cameras","author":"SS Healy","year":"2023","unstructured":"Healy SS, Stephan CN (2023) Focus distance estimation from photographed faces: a test of PerspectiveX using 1,709 frontal and profile photographs from DSLR and smartphone cameras. Int J Legal Med In Press"},{"key":"3081_CR41","first-page":"241","volume-title":"Anthropometry of the Head and Face","author":"LG Farkas","year":"1994","unstructured":"Farkas LG, Hreczko TM, Katic M (1994) Craniofacial norms in North American Caucasians from birth (one year) to young adulthood. In: Farkas LG (ed) Anthropometry of the Head and Face. Raven Press, New York, pp 241\u2013336"},{"key":"3081_CR42","doi-asserted-by":"publisher","first-page":"331","DOI":"10.1002\/ajpa.1330100318","volume":"10","author":"JA Gavan","year":"1952","unstructured":"Gavan JA, Washburn SL, Lewis PH (1952) Photography: an anthropometric tool. Am J Phys Anthropol 10:331\u2013353. https:\/\/doi.org\/10.1002\/ajpa.1330100318","journal-title":"Am J Phys Anthropol"},{"key":"3081_CR43","doi-asserted-by":"publisher","unstructured":"Kingslake R (1992) Optics in photography. SPIE, Washington. https:\/\/doi.org\/10.1117\/3.43160","DOI":"10.1117\/3.43160"},{"key":"3081_CR44","doi-asserted-by":"publisher","first-page":"205","DOI":"10.1007\/s10278-004-1014-6","volume":"17","author":"A Rosset","year":"2004","unstructured":"Rosset A, Spadola L, Ratib O (2004) OsiriX: an open-source software for navigating in multidimensional DICOM images. J Digit Imaging 17:205\u2013216. https:\/\/doi.org\/10.1007\/s10278-004-1014-6","journal-title":"J Digit Imaging"},{"key":"3081_CR45","unstructured":"Blender Development Team (2022) Blender (Version 3.1.0) [Computer Software]"},{"key":"3081_CR46","doi-asserted-by":"publisher","first-page":"863","DOI":"10.1007\/s00414-015-1292-1","volume":"130","author":"J Caple","year":"2016","unstructured":"Caple J, Stephan CN (2016) A standardized nomenclature for craniofacial and facial anthropometry. Int J Legal Med 130:863\u2013879. https:\/\/doi.org\/10.1007\/s00414-015-1292-1","journal-title":"Int J Legal Med"},{"key":"3081_CR47","doi-asserted-by":"publisher","first-page":"113","DOI":"10.1016\/j.forsciint.2017.09.016","volume":"280","author":"CN Stephan","year":"2017","unstructured":"Stephan CN (2017) 2018 tallied facial soft tissue thicknesses for adults and sub-adults. Forensic Sci Int 280:113\u2013123. https:\/\/doi.org\/10.1016\/j.forsciint.2017.09.016","journal-title":"Forensic Sci Int"}],"container-title":["International Journal of Legal Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1007\/s00414-023-03081-3.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/article\/10.1007\/s00414-023-03081-3\/fulltext.html","content-type":"text\/html","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/link.springer.com\/content\/pdf\/10.1007\/s00414-023-03081-3.pdf","content-type":"application\/pdf","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,11]],"date-time":"2023-10-11T07:16:50Z","timestamp":1697008610000},"score":1,"resource":{"primary":{"URL":"https:\/\/link.springer.com\/10.1007\/s00414-023-03081-3"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2023,9,13]]},"references-count":47,"journal-issue":{"issue":"6","published-print":{"date-parts":[[2023,11]]}},"alternative-id":["3081"],"URL":"https:\/\/doi.org\/10.1007\/s00414-023-03081-3","relation":{},"ISSN":["0937-9827","1437-1596"],"issn-type":[{"value":"0937-9827","type":"print"},{"value":"1437-1596","type":"electronic"}],"subject":[],"published":{"date-parts":[[2023,9,13]]},"assertion":[{"value":"26 April 2023","order":1,"name":"received","label":"Received","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"28 August 2023","order":2,"name":"accepted","label":"Accepted","group":{"name":"ArticleHistory","label":"Article History"}},{"value":"13 September 2023","order":3,"name":"first_online","label":"First Online","group":{"name":"ArticleHistory","label":"Article History"}},{"order":1,"name":"Ethics","group":{"name":"EthicsHeading","label":"Declarations"}},{"value":"This work is exempt from ethics approval. The work concerns photographs of the second author taken with full consent and the use of a pre-existing CT scan of the second author, again with full consent.","order":2,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethics approval"}},{"value":"The second author consents to the publication of various images of his face and skull in this work.","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent to participate"}},{"value":"The authors declare no competing interests.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Competing interests"}},{"value":"The views and opinions expressed herein are entirely those of the authors. They are not to be construed as official views of any institutions, editorial boards, or governing boards to which the authors may be affiliated.","order":5,"name":"Ethics","group":{"name":"EthicsHeading","label":"Disclaimer"}}]}}