Determine Big Four with Forensic Anthropology

Determining the Big Four with

Forensic Anthropology

Laurie Beranek

Mesa Community College

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ABSTRACT

This paper researches the "Big Four" in Forensic Anthropology. The "Big Four" determines the sex, age, ancestry and stature of human remains. Research was conducted with five books and class notes from a Forensic Anthropology class. A book based on Dr. Maple's work, a forensic anthropologist based in Florida. Two books are general books on Forensic Anthropology. The other two books are based on the research done by Dr. Bill Bass. Dr. Bill Bass runs the "The Body Farm" at the University of Tennessee's Anthropology Research Facility. The Body Farm is the world's first and only laboratory dedicated to the study of human decomposition. Determining the "Big Four" is very important in assisting with criminal investigations. Once you have the age, sex, ancestry and stature of the skeletal remain, the criminal investigator can start looking at possible victims or missing persons with hopes of being able to positively identify the victim. Once the victim is identified, then there is proof a crime has been committed and the investigation can move forward, in apprehending and convicting the offender.

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Determining the "Big Four" with Forensic Anthropology

A Forensic Anthropologists specializes in the analysis of human skeletal remains in a medicolegal sense. They can be an invaluable resource when a portion or all of the soft tissue is gone. Forensic Anthropologists assist criminal investigations by analyzing decomposed human remains to establish the identity of the deceased. This is accomplished by determining the "big four": sex, age, ancestry and stature.

A good place to start with the identification of the skeletal remains is with sex. This is one of the easiest tasks as there are only two choices. Sexual dimorphism which is the differences in the size and shape that exits between males and females helps in determining the sex of the remains. The marked appearance of sexual dimorphic traits on bones is not apparent until puberty so it is easier to assign a sex of a skeleton to an adult as opposed to a subadult. The two main skeletal features used to determine the sex are the skull and the pelvis.

The female skull retains more gracility and smoothness with thinner less prominent ridges and crest. Male skulls are relatively large and more robust with rougher surface areas. The supraorbital ridge is very noticeable in males but practically absent in females. Additionally, the female's forehead tends to be rounded while in males it is inclined. Males also possess squarer chins, whereas the female chin is usually pointed. (Ferllini, 2002) While the skull is helpful in the determination of sex, the bones of the pelvis provide an even more abundant source of information. In females, the pelvic inlet is broad, rounder, and generally wider with a large diameter and a wide subpubic angle designed to accommodate child bearing. In males, the pelvis is generally higher and narrower, with the pelvic outlet obstructed by a curved sacrum and coccyx, as well as a narrow subpubic angle creating a heart-shaped superior aperture. There are many traits that can betray the truth to the observer, but the pelvis is usually more trustworthy than the skull for determination of sex. (Nafte, 2000)

Once the sex has been established, the age of the individual at death must be determined. Determining the age of an individual at the time of death provides an essential piece of information that may lead to a positive identification. One factor used to estimate age is the cranial sutures. At birth, our cranial vault consists of seven separate bones, by age five, these all knit together at the cranial sutures, zigzagging joints that interlock. Around age thirty, the sutures generally begin to fill in with bone and smooth out; eventually they may become completely invisible or obliterated. (Bass & Jefferson, 2007)

Another helpful factor is epiphysis union. During our youth, the ends of our long bones called the epiphyses are not yet fused to the shafts; instead they're connected to the shafts by cartilage allowing the shafts to grow throughout childhood. Beginning in early adolescence, the epiphyses begin to fuse, gradually halting the growth of the bones shafts. (Bass & Jefferson, 2007) The epiphyses fuse at different times throughout the growth cycle. At age twenty-five the last epiphysis fuses which is the medial