Overcoming the chaotic numerology of osteometry. A proposal for a univocal numeric coding system for osteometric measurements of the human skeleton

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Introduction
Osteometry is not only one of the most historical and essential parts of physical anthropology; skeletal measurements still have a very relevant role in forensic anthropology because they allow the objectification of morphological characteristics, outlining the biological profile of unknown skeletal remains and understanding human physical variation (Bass, 1987;France, 1998;Scheuer and Black, 2000;Dabbs and Moore-Jansen, 2010;Plochocki, 2011).
Over the decades (Rollet, 1888;Hrdlicka, 1952;Olivier, 1960), various methods have been developed using different coding systems for measurements, each being used by different researchers, but none reaching a universal consensus.Especially in Europe, one of the most popular codifications is from Martin-Saller (1957); other codes often used in the USA are by Howells (1973) and by Buikstra and Ubelaker (1994).A non-shared language can create an impasse and miscommunication between scientists and forensic practitioners in the scientific community, which is becoming ever more global and international.
However, forensic sciences urgently require standard analytic methods and data collection: the Frye and Daubert principles, the Joint POW/MIA Accounting Command (JPAC) experience, and recent AAFS meetings (Bono, 2011) all stressed the importance of scientific evidence based on the requirements of relevance, reliability and validity.The use of quality assurance is essential where a high degree of reliability is required, and therefore a univocal and standardized coding system should be introduced into physical/forensic anthropology (Byrd and Sava, 2009;Byrd, 2009).
Similar problems have been faced by odontologists who are involved in mass fatalities and international casework.The odontological community has solved this problem with the FDI World Dental Federation notation ISO 3950, where quadrants are numbered from 1 to 4 in permanent and from 5 to 8 in deciduous dentition.The numbers proceed clockwise from the upper right quadrant to the lower right, and the teeth are numbered from the midline to the posterior.

Imperfections of the traditional coding systems
In order to develop a new shared codification model, some imperfections in the traditional coding systems must be overcome.
First of all, one obstacle in the Martin-Saller system (Martin and Saller, 1957) is that all measurements are divided into chapters corresponding to single bones and are numbered with an arithmetic progression.This system can be ambiguous because the numbers are not univocal.For example, measurement number 1 (MS 1) can indicate the maximum length of the skull, the femur and all the other long bones.
Howells coding identifies the measurement by an abbreviation in capital letters of its description; this system presents a problem when a long or complex name identifies a measurement or if new measurements are created.
The USA Standards by Buikstra and Ubelaker (1994) has poor proactivity because measurements are numbered in a non-interrupted sequence from the skull to the calcaneus; therefore, new measurements cannot be simply introduced to the sequence without creating confusion.

The new coding system
The new coding system proposed is based on a three-number codification, where numbers are divided by full stops (i.e.#.#.#).The first number will indicate the anatomical area to which the measurement refers: 1 -cranium 2 -upper limb 3 -lower limb 4 -rachis 5 -thoracic girdle 6 -pelvic girdle The second number will indicate the single bone or the topographic region in the cranium, as shown in Table 1.
The first two numbers of the code rapidly identify which area of the body and on which bone the anthropometrical data is recorded.The third and final number is an arithmetic progression that identifies each measurement, allowing future researchers to introduce new measurements without scrambling the entire series.
Tables from 2 to 21 present a selection of measurements and their correspondence with the new coding system and previous codifications, including British (Brothwell, 1981) and Fordisc® systems.The proposed selection includes only some of the measurements in Howells (1973) or Buikstra and Ubelaker (1994), but it also provides for new ones, most of which come from Martin and Saller (1957) or recent forensic scientific literature (Baker et al., 1990).All the measurements reported in the present proposal are included in the «Forensic Protocol for anthropometric measurement of human skeletal remains» developed in Italy (Borrini, 2011).This new protocol has been developed with detailed instructions which provide standard operating procedures (SOP) for measuring human bones.The measurements are mostly from Martin and Saller (1957), but they have been rewritten as SOP, providing clear, detailed and explicit directions on how to record each measurement and from which landmark.Anatomical reference points have been thorough specified, and the measuring technique has not been presented as mere definitions as in the past literature.Instead, each action (e.g., placement and movements of the callipers) has been described in short sentences, and the protocol includes step-by-step instructions for the operator, which indicate in a clear, unambiguous and precise manner how to record each measurement, from which landmark to proceed, and which instrument to use.Consequently, a further benefit of this protocol is overcoming the problems related to the lack of universal consensus on recording osteometric measurements.

Conclusion and future developments
The author presents to the scientific community of biological and forensic anthropologists a proposal for a new measurement coding in order to create a shared system for osteometry.
The proposed system is an integral part of the «Forensic Protocol for anthropometric measurement of human skeletal remains» developed at the University of «Tor Vergata» (Borrini, 2011).The coding and the protocol have been successfully applied to various historical (Franchi et al., 2000;Pintaudi et al., 2012;Gnes et al., 2018;Baldoni et al., 2018) and Italian forensic cases (Borrini, 2015) in a five-year research project at the University of Florence.
Currently, this protocol is used by various Italian and international (Valoriani, 2019) Universities and expert witnesses appointed by the Italian State Prosecutor Office.It is hoped that the proposed system will enable researchers and practitioners to speak the same language and communicate their findings.A scientific community with a common language will be more inclusive and allow the comparison of data from different skeletal populations and pursuing justice around the world.
Tab. 2. Correspondence between the proposed coding system and the traditional classifications for neurocranial measurements.
Tab. 3. Correspondence between the proposed coding system and the traditional classifications for facial measurements.
Tab. 4. Correspondence between the proposed coding system and the traditional classifications for orbital measurements.
Tab. 5. Correspondence between the proposed coding system and the traditional classifications for nasal measurements.
Tab. 6. Correspondence between the proposed coding system and the traditional classifications for maxillary measurements.
Tab. 7. Correspondence between the proposed coding system and the traditional classifications for mandibular measurements.
Tab. 8. Correspondence between the proposed coding system and the traditional classifications for measurements of the humerus.
Tab. 9. Correspondence between the proposed coding system and the traditional classifications for measurements of the ulna.
Tab. 10.Correspondence between the proposed coding system and the traditional classifications for measurements of the radius.
Tab. 11.Correspondence between the proposed coding system and the traditional classifications for measurements of the femur.
Tab. 12. Correspondence between the proposed coding system and the traditional classifications for measurements of the tibia.
Tab. 13.Correspondence between the proposed coding system and the traditional classifications for measurements of the fibula.
Tab. 15.Correspondence between the proposed coding system and the traditional classifications for measurements of the vertebrae from C3 to L5.
Tab. 16.Correspondence between the proposed coding system and the traditional classifications for measurements of the vertebrae C1 and C2.
Tab. 17. Correspondence between the proposed coding system and the traditional classifications for measurements of the sacrum.
Tab. 18. Correspondence between the proposed coding system and the traditional classifications for measurements of the scapula.
Tab. 20.Correspondence between the proposed coding system and the traditional classifications for measurements of the os innominatum or os coxa.
Tab. 21.Correspondence between the proposed coding system and the traditional classifications for measurements of the pelvis.For these measurements both the os coxae and the sacrum are articulated.

Tab. 1 .
The first two numbers of the coding system refer to the anatomical area and the bone to which the measurement refers.For the cranium, the second number indicate the anatomical region.