In order to correctly identify found human remains using skeletal material, forensic anthropologists focus on determining as many physical characteristics as possible, including age, gender, stature, and body type. Methods of estimation are quite reliable, though not 100% accurate, especially regarding phenotypic representations such as weight distribution or race. This paper will outline the methods used to determine these characteristics, and explain some of the problems forensic anthropologists face when attempting to match an individual with a set of skeletal remains.
The determination of gender is relatively easy given an intact adult skeleton, and has about an 85-95% accuracy rate. Human males and females are sexually dimorphic; the pelvis differs in shape and size, though this measurement is most accurate after adolescence. The average size of the crania also differs between males and females. Gender differences in the overall size of the femur head can also be used to estimate sex, but problems arise when using these measurements alone. In general, male skulls are large and rugged; with larger, broader palates and large occipital condyles. Female skulls are small and smooth; palates and occipital condyles are smaller. However, because these are relative measurements (some men may be gracile, and a woman could be rugged) there is a degree of uncertainty. Another problem emerges when considering sex differences between races; in order to determine race, gender must be known but to determine gender, race must be known. This conundrum illustrates the importance of a complete set of skeletal remains as the pelvis is a more reliable tool in identifying sex than the skull.
Determining age at death can also be relatively accurate, depending on the amount of time that has elapsed since death and condition of the remains. Some attributes of bone that are considered are dental eruption and occlusion, cranial suture closures, bone histology, and degenerative conditions related to age. Dental eruption is quite a useful tool in the identification of skeletal remains of children up to around age 15 because teeth erupt at prescribed, known intervals. While dental occlusion is useful in the estimation of age, it can also be misleading in certain situations. Diet affects occlusion, and an adolescent who consumes a diet with high grit content could show more wear than a much older adult. Cranial suture closures can be reliably observed in remains of individuals who were over the age of 40. Evidence of age-related conditions such as arthritis and osteoporosis can provide assurance of accuracy in estimating the age at death of older individuals. However, there are problems in this area as well, since young people may be affected by these diseases, or conditions and injuries which leave similar traces on bone.
The ability to determine stature and weight is also important for the identification of remains. When all twelve upper and lower long bones are present (this would be optimal but of course is not always the case) the forensic anthropologist can use the average lengths of the bones and a standard error to estimate living height. Once a height is determined, weight can be estimated using another standard error.