Age, Sex, and Stature Estimations from Clavicles by Morphology, Osteometry and Radiological Image Analysis in a Thai Population

Abstract

Skeletal remains examinations require a specific-population data research in each population group in order to obtain biological profiles of the deceased. Since the differences between ethnic groups, dietary, daily routines, and genetics can affect the morphological appearances of the skeletal remains. The main objectives that the forensic practitioners have to discover after examinations are ancestry, sex, age, stature, postmortem interval, injuries, or pathology that may lead to the presumption of the cause and manner of death. At the crime scene, sometimes important bones which can identify biological profiles such as a skull, a pelvic bone, and limb bones may not be completely discovered, Therefore, the authors of this study are interested in researching the creation of biological data such as age, sex and stature from the clavicle, since they are bones that can be commonly discovered at the crime scene. Moreover, this bone can be conveniently removed for examination in case that the remains still has some soft tissues attached or could be useful in the decomposed body which is not yet able to identify, which will make it more useful for the forensic practitioners to examine unidentified corpses. This study is an observation on the degenerative morphological changes of the sternoclavicular joints and attempt to classify these changes into age groups. Moreover, clavicles are measured to establish sex and stature estimation equations. After that, radiographs are taken and cortical thicknesses are measured by applying Radiant Dicom Viewer program and using the data obtained to create sex, stature and age estimation equations.The observations of 128 pairs of clavicles (104 Male, 24 female) yielded results as followed : the youngest age that fused epiphysis can be seen is 24 years old in male and 26 years old in female samples. The clavicles of adults aged 30 to 39 years old usually have regular rim and surface of the sternal end. The clavicles of adults aged 40 to 49 years old usually have slight irregular rim and surface of the sternal end. The clavicles of old adults, aged more than 50 years old group usually have obvious irregular rim, surface of the sternal end and sometimes osteophytes at 1st rib articulation surface can be observed. Measurements in 137 pairs of clavicles (112 Male, 25 female) yielded results as followed : sex estimation equation shows a combination between maximum length and robustness index yields best results with 93.4% correctly classified. Moreover, the univariate discriminant analysis indicates that maximum length yields best results for sex discrimination with 89.8% correctly classified. Whereas, in regression analysis which applied 3 variables as followed : maximum length, anterior-posterior diameter at medial 1/3 of clavicle, and height of sternal end of clavicle can yield R2 = 0.490 with the standard error of estimation at 5.238 centimeters for stature estimations in unknown sex individuals, univariate regression analysis from maximum length have R2 = 0.312 with the standard error of estimation at 6.035 centimeters. Height of sternal end clavicle can also estimate stature in cases which fragmented clavicles are recovered in crime scenes which yields R2 = 0.238 with the standard error of estimation of 6.353 centimeters.Measurements from radiographs of 99 pairs of clavicles (112 Male, 25 female) yield results as followed : sex estimation can be derived from applying maximum length into discriminant analysis which indicates best results for sex discrimination with 88.9% correctly classified. Stature estimation from radiographs can be derived from maximum length of clavicles which yields R2 = 0.363 and standard error of estimation of 5.562 centimeters. Regarding to an age estimation from radiological image analysis, applying posterior index at mid-diaphysis of clavicle into age estimation equation yields R2 = 0.081 and standard error of estimation 11.582 years.