Cite as: Archiv EuroMedica. 2022. 12; 3: e1. DOI 10.35630/2199-885X/2022/12/3.30

Received in revised form 28 April 2022;

Accepted 29 April 2022

Positive
identification of unknown corpses and bone remains often pose
significant challenges for practitioners and requires the use of
forensic anthropological methods. The purpose of this study was
to** **develop
new methods for reconstructing
the antemortem biacromial breadth of the shoulders (BAB) using
osteometric measurements of the human clavicle. For this purpose,
bone samples from two anatomical collections were used: collection of
the Department of Anthropology of Lomonosov Moscow State University
and collection of the Russian Center for Forensic Medical Examination
(Moscow, Russia). The study showed the possibility of correct
reconstruction of BAB using regression equations with expanded (13)
or reduced (3-5) sets of osteometric parameters. The methods
described in the article can be applied both in forensic context and
in anthropological studies.

**Keywords:
– **clavicle,
biacromial breadth of the shoulders, shoulder breadth, linear
multiple regression, forensic
anthropology, human identification.

Positive identification of unknown corpses and bone remains often pose significant challenges for practitioners and truly considered as one of the cornerstones of forensic medicine. A medical examiner can be involved in the identification of human remains due to the peculiarities of the current geopolitical situation, in cases of man-made or natural disasters, as well as when investigating the cases of homicide. Working with bone remains means using the methods of physical anthropology widely as they make it possible to estimate the four most important primary identifiers (sex, age, race, body length) and carry out the identification with minimal time and without the use of complex and expensive equipment [1]. Positive identification of an unknown person largely depends on the degree of preservation of the objects submitted for examination. The clavicles, along with other bones of the shoulder girdle, are an important object for forensic osteological research [2], as they have some important features: 1. as a rule, the clavicles are quite well preserved; 2. they reflect individual characteristics peculiar to a particular person (for example, the presence of a rhomboid fossa, signs of osteoporosis or the consequences of a fracture) and common features such as sex, age, body type, skeleton massiveness and somatometric signs including body length and shoulder breadth.

Shoulder breadth (biacromial, BAB) is the horizontal distance between the right and left acromial landmarks (ac-ac). The average values of BAB in Caucasian populations are 386.06±23.09 mm for men and 349.26±20.88 mm for women [3]. There are several methods for BAB reconstruction from the clavicles developed over the past 50 years and using different approaches [4-7]. Despite this fact, the need for the development of new osteometric methods for the purposes of forensic medicine that meet the criteria of validity, reliability and objectivity is still great.

* The
aim of the study *was
to

Bone samples from two documented
anatomical collections were used: series 1 – a collection of
skeletons from the Department of Anthropology of Lomonosov Moscow
State University (Russians, mid-20th century, N=83); series 2 –
«RCFME» (Russians, 20^{th} century, N=152), bone samples from the osteological collection of the
Russian Center for Forensic Medical Examination (Moscow, Russia). The
total number of bone samples examined was 235. The definitions of
clavicle measurements follow the standard methodology [8-9]:

СLМ-1. The total length of the clavicle: the distance between the most medial point of the sternal end of the clavicle and the most lateral point of its acromial end.

СLМ-4. The length of the clavicle shaft: the distance from the sternal end of the clavicle to the most forward-protruding point of its diaphysis. The value is measured in parallel with the total length of the clavicle (CLM-1).

СLМ-5. The clavicle circumference: the perimeter of the clavicle in the middle of the shaft. The measurement site is defined as half the total length of the clavicle.

СLМ-6. The largest diameter of the clavicle: the empirically determined maximum size at the mid-shaft of the bone.

СLМ-6A. The sagittal diameter of the clavicle: the straight distance between the anterior and the posterior edges of the mid-shaft of the clavicle.

СLМ-7. The smallest diameter of the clavicle: the empirically determined minimum size at the mid-shaft.

СLМ-7A. The vertical diameter of the clavicle (clavicle thickness): the distance between the cranial and the caudal surfaces of the mid-body of the clavicle.

СLМ-8. The height of the clavicle shaft arc: the height of the most forward-protruding point of the anterior side of the clavicle shaft edge above the straight line connecting the most retracted points of the sternal and the acromial ends of the clavicle at its posterior side.

СLМ-8A. The depth of the sternal end arc: the projection distance from the deepest point of the sternal end arc to the tangent passing through the apex of the acromial end arc and the posterior edge of the sternal end.

СLМ-9. The height of the arc of the clavicle acromial end: the height of the most forward-protruding point of the anterior side of the clavicle acromial end above the straight line connecting the most retracted points of the sternal and the acromial ends of the clavicle at its posterior side.

СLМ-9A. The depth of the acromial end arc: the projection distance from the deepest point of the acromial end arc to the tangent passing through the apex of the sternal end arc and the anterior edge of the acromial end.

СLМ-10. The length of the deltoid tuberosity: the straight distance between the most anterior point of the clavicle acromial end to the most medial point of its deltoid tuberosity.

Osteometric measurements were collected using a standard sliding caliper, osteometric board, and millimeter measuring tapes. Pearson parametric correlation analysis was performed to study the relationship between osteometric clavicle measurements and antemortem shoulder width (p<0.05). The linear multiple regression equations were calculated using the StatSoft STATISTICA 10.

After data
processing, two groups of linear multiple regression equations were
obtained: 1. With a reduced set of osteometric measurements including
the total length of the clavicle (CLM-1), the length of the clavicle
shaft (SLM-4), the clavicle
circumference
(SLM-5), the length of the deltoid tuberosity (SLM-10); 2. With an
extended set of 13 measurements. In order to select the measurements
for the resulting equations correctly, the correlation analyses was
performed between antemortem BAB and osteometric
measurements of the human clavicle.
Moderate correlations were found between BAB and СLМ-5
(r=0,28); BAB and CLM-6 (r=0,27);
BAB and CLM-8 (r=0,26).
Strong correlation was observed only
between BAB and CLM-1_{dex+sin }(r=0,96).

Table 1 shows
the coefficients of the regression functions (models). To work with
these models, the researcher needs to substitute the values of the
clavicle osteometric measurements in the following equation: *y=a+b*_{1}*х*_{1}*+b*_{2}*х*_{2}*+...+b*_{n}*x*_{n},
where *a* – the constant, *b *–
osteometric parameter, *х* – regression coefficients. The sex is not taken into account.

**Table
1.** Shoulder
breadth (biacromial) estimation from
the clavicle using
the linear
multiple regression

Measurements | Coefficients | ||

Model 1 | Model 2 | Model 3 | |

CLM-1_{dex} |
0,921 | 0,470 | 1,188 |

CLM-1_{sin} |
0,763 | 0,794 | -0,009 |

CLM-4 | 1,181 | 0,571 | |

CLM-5 | 1,782 | 2,761 | |

CLM-6 | 4,125 | ||

CLM-6A | -2,020 | ||

CLM-7 | -2,856 | ||

CLM-7A | -3,560 | ||

CLM-8 | 1,945 | ||

CLM-8A | -0,376 | ||

CLM-9 | -0,351 | ||

CLM-9A | 3,071 | ||

CLM-10 | 0,347 | -1,168 | |

Constant | 104,213 | 49,950 | 49,530 |

R | 0,533 | 0,670 | 0,823 |

The adequacy of the obtained models was evaluated using the multiple correlation coefficient R, which varies within 0≤R≤1 and, as it approaches 1, indicates an increase in the closeness of the relationship between two or more variables. In all cases, the models for which the R statistics exceeds 0,5 were selected. The best result, as can be seen in Table 1, was demonstrated by Model 3, which includes the maximum number of measurements (R=0.823).

A noteworthy feature was the presence of correlations between the shoulder width and the longitudinal size of the clavicles (the total length of the clavicle, CLM-1), and also between the shoulder width and transverse dimensions, which also contribute to the resulting regression models (the clavicle circumference, CLM-5; the largest diameter of the clavicle, CLM-6). These results are consistent with previous studies [6] and indicates that for the correct calculation of BAB, it is not enough to measure only the total length of the clavicle, as recommended in [5] and [7].

The study showed the possibility of reconstruction of the biacromial breadth of the shoulders from clavicle osteometrics. Using the linear multiple regression, 3 diagnostic models were calculated for reconstruction of BAB regardless of the sex using an expanded or a reduced set of measurements, which is important when working with a limited set of isolated skeletal elements or their fragments. The method described above can be applied for comparison between osteometric and anthropometric datasets both in forensic context and in anthropological studies.

Dmitriy Sundukov designed the study; Askold Smirnov collected, analysed, interpreted data and provided the table. Askold Smirnov and Dmitry Sundukov prepared the manuscript for submission.

- Iscan M. Y., Steyn M. The Human Skeleton in Forensic Medicine. Charles C. Thomas Publishers, Springfield. 2013.
- Demir U., Etli Y., Hekimoglu Y. , Kartal E., Keskin S., Yavuz А., Asirdizer M. Sex estimation from the clavicle using 3D reconstruction, discriminant analyses, and neural networks in an Eastern Turkish population // Leg Med (Tokyo) – 2022. Vol. 56. – P. 102043. DOI: 10.1016/j.legalmed.2022.102043
- Karadayi B, Ozaslan A, Kolusayin MO, Kaya A. Stature estimation from bi-acromial and bi-iliocristal measurements // Romanian Journal of Legal Medicine. – 2011. Vol. 19, N3. P. 171-176. DOI: 10.4323/rjlm.2011.171
- Kriesel G.Zagadnienie okreslania budowy somatycznej na podstawie ludzkich szczqt köw kostnych. Torun,1970.
- Piontek J. Reconstruction of individual physical build features in the investigated praehistoric populations // Collegium Anthropologicum. – 1979. N2. P. 251-253.
- Zvyagin V.N., Galitskaya O.I.,
Grigor'eva M.A. Opredelenie prizhiznennykh somaticheskikh razmerov
tela cheloveka pri sudebno-meditsinskoi ehkspertize skeletirovannykh
i sozhzhennykh ostankov / Meditsinskie tekhnologii, ispol'zuemye pri
proizvodstve sudebno-meditsinskikh ehkspertiz. M.: Kompaniya Planeta
Zemlya, 2012. P. 96-130.
*[In Russ.]**.* - Ruff Chr.B. (ed.) Skeletal Variation and Adaptation in Europeans: Upper Paleolithic to the Twentieth Century. John Wiley & Sons, Inc, 2018.
- Voroncova E.L. Morfologicheskaja izmenchivost' kostej plechevogo pojasa i grudiny cheloveka. Avtoreferat dissertacii kand. nauk. М., 2005. [In Russ.].
- Sehrawata J.S., Pathakb R.K. Variability in anatomical features of human clavicle: Its forensic anthropological and clinical significance // Translational Research in Anatomy. – 2016. Vol. 3–4, P. 5-14. DOI: https://doi.org/10.1016/j.tria.2016.08.001