|
|
| Forensic
Anthropology |
| When bones or skeletons are found,
they are taken to a forensic laboratory for examination. The job of
an anthropologist, a forensic scientist specializing in the
area of bones, is to examine the bones, to possibly deduce the gender,
age, height, race, as well as medical history and manner of death. |
|
Select one of the following topics to read more:
--> The
basic task
--> Growth
rate
--> Gender
--> Height
--> Bone
defects
|
| |
| The
Basic Task |
|
| The first step an anthropologist takes
during the examination of bones, is to find out whether the bones
are human or animal, as sometimes certain animal bones will resemble
that of human bones. Once this has been determined, the next step
is finding the age of the bones by noting the growth and decay that
has occurred in the bones. |
| |
| Growth
Rate |
|
|
Teeth that have or have not grown can also reveal the age
of the skeleton, as young children will have not lost their
milk teeth and at the age of 18, wisdom teeth first
appear. During the teenage years, bones become thicker and
larger and fuse together in a process known as 'ossification'.
Ossification occurs in 800 points of the body and is the best
guide to revealing the age of a child's skeleton. An example
of ossification occurs in the arms, where at the age of six,
the two bone plates form at either end of the outer forearm
(radius).
At the 17 in males and 20 in females, the lower bone plate
and the radius fuse together and soon after, the upper
bone plate and radius fuse together. The bone in the body
that finishes growing last is the collarbone, which
ceases growth at 28 years. In the bones of the elderly, degeneration
begins to occur. Anthropologists will look for tiny spikes
that start to appear on the edges of the vertebrae,
the wearing of teeth due to age and joints that show signs
of arthritis. All of the bones in the body will deteriorate
with age.
|
|
| *
Comparison of a 5 yr to a 60 yr old skull. Photo courtesy of
Valeri
Craigle and the Spencer
S. Eccles Health Sciences Library. |
|
| |
| Gender
|
|
 |
When determining
male and female in a skeleton, anthropologists look at the skull
and hip bones, as there lie clues to the sex of the skeleton.
The skull has three points in determining gender. These are
the ridges located above the eyes, the bone situated just below
the ear and the occiput, the bone located at the lower
back of the skull. The latter two bones are muscle attachment
sites, all of which are more prominent in men, indicating greater
strength. The difference in hips is very obvious, as a man's
hip are narrower and a women's hips are wider, being built for
child bearing. However there are smaller differences in other
bones, which anthropologists rely on when there is no hip or
skull bone. |
| *The
space between the hips of a woman are much larger than that
of a man. Photo courtesy of Valeri
Craigle and the Spencer
S. Eccles Health Sciences Library. |
|
| |
| Height |
|
| Determining the height of a skeleton
involves reassembling the skeleton and measuring the length of significant
bones. By adding 10-11cm or four inches onto the bone length, it accounts
for the missing tissue and muscle. If parts of the skeleton
are missing, certain individual bones are used as a height guide.
The longer the bone is, the better and more accurate the estimate
will be, so the femur is measured first. The human height measures
roughly two and two thirds the length of the femur, though
it also depends on the race and sex of the skeleton. |
| |
| Bone
Defects |
|
| Disease, injury and birth
defects are also revealed in the bones. Birth defects such as spina
bifida, some infectious diseases, poor diet and cancer can all
be damaging to the bones. In the case of injuries, broken bones and
mended bones are easily visible and because they are so easily visible,
mended bones can reveal identity. Work and hard labour leave damage
such as occupational arthritis, which visibly changes the appearance
of affected joints. The skeletal remains of someone who has died a
particularly violent death are evident in the bones. Bullet wounds
leave round holes, sharp weapons cause chips to be taken out of the
bone and fractures in the bones also suggest forms of violence. Distinguishing
between fractures that occurred before and after death is difficult,
but there are some clues that are helpful. For example, the bones
of a deceased person break differently compared to the bones of a
live person and healing at the edge of a fracture indicates injuries
during life. |
 |
| *
The wire left in bone to repair a fracture may give away the unknown
identity. Photo courtesy of Valeri
Craigle and the Spencer
S. Eccles Health Sciences Library. |
|
|
