Anth 300 Forensic Anthropology
Dr. Darlene Applegate
LAB 7: ESTABLISHING FORENSIC
After human remains have been discovered, the task of investigating
those remains begins. If the human remains are skeletonized,
decomposed, desiccated, dismembered, burned, or commingled, the
expertise of a forensic anthropologist is required. According to
Pickering and Bachman (1997), forensic analysis may be conceived as a
ten-step process guided by key questions.
The first three questions allow investigators to establish the forensic
context of a case. In other words, does the case have
significance, such that a detailed forensic analysis is warranted?
Ideally, this determination will be made by a forensic anthropologist
in the field at the site where the remains were discovered. Whether
accomplished in the field or in the lab, the process of assessing the
forensic significance is an important one. This exercise introduces the
basic principles of establishing forensic context.
- Is it bone?
- Is it human?
- Is it modern?
- What bones are present?
- How many individuals are present?
- What is the biological profile of each individual?
- What was the context of death?
- How long has the individual been dead?
- How have the bones been altered since death?
- Who is the individual?
- to distinguish bone from other material
- to distinguish human bone from non-human bone
- to distinguish fresh bone from dry bone
- forensic context
- epiphysis (epiphyses)
- modern / contemporary / recent
- fresh bone
- dry bone
- review Chapter 3 of the Byers (2008) textbook
- review Chapter 3 of the Byers (2008) lab manual
IS IT BONE?
The first step of forensic investigation involves confirming whether or
not the discovered material is indeed bone. Complete skeletal elements
often are easily identified, but skeletal fragments may resemble
objects made of non-bone materials. Natural materials and objects that
may be confused with bone include tree roots, wood fragments, shell,
and rocks, especially light-colored sedimentary rocks. Human-made
materials and objects that may be confused with bone include plastic,
styrofoam, foam insulation, sponge, plaster, mortar, and even discarded
gum. The more weathered the cultural materials and objects, the more
likely they are to be confused with bone.
Both macroscopic (with the unaided eye or a low-power magnifying glass)
and microscopic examination can be used to identify bone. Three
macroscopic variables that may be used to distinguish bone from other
materials and objects are surface texture, internal structure, and
|compact, some degree of
|varies from creamy white to
yellowish to brownish; dull luster
|porous, spongy texture
|compact, some degree of
||various shades of white, gray,
|usually not porous, not spongy
|exterior is dark or light in
color when fresh but weathers to shades of white and gray; pearly luster
|not porous, not spongy
|not compact, fibrous
|various shades of brown; dull
|compact, smooth to slightly
|undecorated pottery varies from
white to cream to yellow to red; dull luster if
unglazed and glassy luster if glazed
|may be porous (especially is not
glazed), not spongy
|various shades of white, gray,
tan; dull luster
|not porous, not spongy
IS IT HUMAN?
Once it is established that bone is present, the next step involves
determining whether or not the bone is human. This determination is
easier to make when complete skeletal elements are present. In
contrast, broken and fragmented human bones, human bones from immature
individuals, and isolated human teeth are more difficult to separate
from non-human specimens, especially by untrained individuals. Forensic
anthropologist Dr. William Bass of the University of
Tennessee-Knoxville’s Department of Anthropology estimated that 25-30%
of the bones brought to him for identification over his career were
non-human (Byers 2008).
Similarities between certain human and non-human skeletal elements are
well documented. Bear and seal hand/foot bones lacking the claw
elements, for instance, are very similar to human hand/foot bones. Deer
vertebrae, especially if the spinous processes are broken off, resemble
human vertebrae. Turtle shell fragments resemble human cranial
fragments in their morphology; turtle shell sutures, however, are more
jagged and regular than human cranial sutures. Forensic anthropologist
Stanley Rhine (1998) recounted a case in which a medical doctor
incorrectly identified a turtle carapace as a human skull cap,
indicating that even physicians who are not specifically trained in
forensic anthropology or osteology may misidentify non-human bones.
In many respects, human bones resemble the bones of other mammals and
animals. Two traits that may be used, however, to distinguish human
from non-human bone are architecture and maturity (Byers 2008). Architecture refers to bone shape
and morphology. Many differences in the architecture of bones from
animal species are due to locomotor differences, especially differences
between quadrupeds and bipeds. Maturity refers to degree of growth
and development. Small bones of nonhuman species will not be confused
with subadult human bones because the latter lack epiphyses.
Differences in Bone Architecture in
Bipeds and Quadrupeds.
- foramen magnum centered on inferior view
- enclosed bony eye socket
- flattened facial area
- triangular palate
- chin on mandible
- mandible is one single bone
- small canine teeth
- foramen magnum posterior on interior view
- open bony eye socket
- enlongated facial area
- elongated palate
- no chin on mandible
- mandible is two bones fused in chin area
- large canine teeth
- vertebral column is s-shaped
- vertebrae have short spinous processes
- vertebral column is c-shaped
- vertebrae have long spinous processes
- sacrum is wide and broad
- ilium is broad and wide
- pelvic outlet is wide
- sacrum narrows in inferior direction
- ilium is elongated
- pelvic outlet is narrow
- body of scapula is a right triangular
- spine of scapula is perpendicular to long axis of body
- acromion process of scapula is pronounced
- rib bodies are more curved
- sternum is broad at body and narrower at gladiolus
- body of scapula is an isosceles triangle
- spine of scapula is parallel to long axis of body
- acromion process is poorly developed
- rib bodies are less curved
- body and gladiolus of sternum are equal width
- smaller processes (e.g., greater trochanter)
- tibia and fibula unfused
- diaphyses are smaller in circumference
- larger processes
- tibia and fibula may be fused
- diaphyses are larger in circumference
IS IT MODERN?
Recall that forensic cases typically involve skeletal remains from
individuals who have been deceased no more than about 50 years. Such
remains are referred to as “modern,” “contemporary,” or “recent.” In
contrast, remains from individuals who have been deceased more than 50
years are referred to as “historic” or “prehistoric” depending on their
As bones are exposed to various weathering agents, they undergo
physical changes that involve loss of moisture and loss of collagen,
the organic component of bone tissue. Because of their condition, then,
recent skeletal remains may be described as “fresh,” whereas non-recent
skeletal remains may be described as “dry.”
There are four lines of evidence used to determine the relative age of
a human bone: condition of interment, personal belongings, body
modifications, and bone condition or state of preservation (Byers
2005). For this lab we will focus on the latter. Bone condition or
state of preservation includes seven traits: color, texture, hydration,
weight, condition, fragility, and soft tissue (Byers 2005), as
|yellowish or brownish
|pitted and grainy
|breaks in spiral fractures
|breaks in perpendicular fractures
|may be present
Carefully examine the three sets of specimens provided in the lab. For
the first set of specimens, distinguish bone from non-bone materials
and objects. For the second set of specimens, distinguish human bone
from non-human bone. For the third set of specimens, distinguish recent
human bone from non-recent human bone.
Your determinations will be based on several lines of evidence. The lab
overview, the Byers textook and lab
manual, and your bone drawings constitute the primary line of evidence.
Second, comparative collections and materials are provided in the lab.
Third, reference books on the human skeleton as well as mammalian
osteology are provided in the lab.
Record all answers neatly and legibly in pencil on the answer sheet
provided by the instructor. Do not provide more information about a
particular specimen than is requested. For example, when asked to
identify a skeletal specimen as human or non-human, there is no need to
identify the particular skeletal element or non-human species.
As always, remember to handle carefully all specimens by keeping them
on styrofoam trays or bubble wrap, wearing gloves with real bones, and
using two hands when examining or transporting specimens. Do not
separate specimens from their labels or bags.
Byers, Stephen N.
2008 Introduction to Forensic
Anthropology: A Textbook (3rd ed.). Allyn and Bacon, Boston.
Byers, Stephen N.
2008 Forensic Anthropology
Laboratory Manual (2nd ed.) Allyn and Bacon, Boston.
Pickering, Robert B. and David C. Bachman
1997 The Use of Forensic Anthropology.
CRC Press, Boca Raton, FL.
1998 Bone Voyage. University
of New Mexico Press, Albuquerque.
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Last updated on January 21, 2008
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