Biology Reference
In-Depth Information
approach and statistical procedures involved in the chapter on demography in this volume
(Chapter 11).
Sex Estimation and Pathology
Sex estimation from the presence of certain types of pathology can be an option if none of
the above discussed methods is possible, though accuracy rates are extremely low. This
method takes advantage of the fact that some diseases affect the sexes differentially (
Reichs,
1986
). For example, juvenile males are more prone to traumatic injury. As a result, the inci-
dence of osteomyelitis (i.e. infection in the bone) occurs at a ratio of young males to females
of 3:1 or 4:1, according to
Reichs (1986)
. This ratio will be extremely population specific,
depending on the sociocultural activities of children. Another skeletal pathology that occurs
more in childhood is sporotrichosis (a type of fungal infection), which affects male juveniles
three times more than female juveniles (
Reichs, 1986
). In adults, ankylosing spondylitis and
gout both occur nine times more in males than females (
Reichs, 1986
). The timing of the onset
of diseases can potentially be useful for sex differentiation. Osgood
Schlatter's disease is
partial avulsion of the tibial tuberosity from overactivity in young adolescents and typically
occurs earlier in females (
DiGangi et al., 2010
). These approaches should only be used as last
resorts if all other methods have been exhausted, with the caveat that it does not allow you to
obtain much more accuracy than the 50:50 probability you would get by guessing.
e
CASE STUDY: DEVELOPING POPULATION-SPECIFIC
SEXING STANDARDS
As described in the Preface, this topic's inspiration stemmed out of research courses held
in Colombia. A massive osteological data collection effort by 34 scientists took place in
Bogot
´
during February 2011. To collect data, the group split up into different data collection
teams. I was personally in charge of the team collecting postcranial metrics. Each individual
on the team was responsible for two to three bones (e.g., those of the forearm). Two other
individuals on the team exclusively measured the entire skeleton of 30 individuals, to test
for interobserver error. One goal of the postcranial metric team was to explore the best
univariate indicators for sex estimation using measurements of the postcranial elements.
As discussed previously, in a recent study of African and European Americans from the
Forensic Database, the postcranial elements demonstrating the most effective sex discrimina-
tion were the femur, tibia, humerus, and scapula (
Spradley and Jantz, 2011
). Thus, the
hypothesis for this project was that the population from Colombia would follow a similar
pattern, with the femur, tibia, humerus, and scapula demonstrating the highest classification
rates.
The sample that was studied is the Colombian Modern Skeletal Collection,
12
which is
curated by the National Institute of Legal Medicine and Forensic Sciences in Bogot´ ,
Colombia. The skeletal collection consists of individuals with known age, sex, and stature
(cadaver or forensic) and is now one of the largest collections of known individuals in South
12
Refer to the Preface in this volume for more information.
