Analysis of Skeletal Remains - Worksheet
Return to The Crime Lab
See also the Analysis of Skeletal Remains Lab,
which involves the use of bone models, as well as actual bones.
In this activity, skeletons will be examined for how they vary according to the
following:




Gender (based on the pelvis & skull)
Race (based on the maxilla, and other characteristics of the skull)
Age (based on general characteristics)
Height (calculated based on the length of individual bones)
Students will be evaluated as to whether or not they correctly identified the gender,
age, and race of the individual.
Being able to determine Left and Right is also crucial to the practice of forensic
anthropology, not only for skeletal reconstruction, but also to determine the number of
casualties. Reference to a complete skeleton is helpful, but one is never around when
you need one (as would happen if you are investigating a skeleton in the woods. That
will not be a part of this activity, but it easily could be.
GENDER
One of the issues of concern to the forensic anthropologist is the gender of the human
remains. There are several things than may, on the surface, be useful to gender
determination, but, on upon closer examination, are not very useful. For example,
females are, on average, shorter than males, but a short skeleton can easily be male.
This is due very simply to the fact that each gender follows a Gaussian distribution
(a.k.a. a Bell Curve).
Image from http://www.bbc.co.uk/science/hottopics/intelligence/iq.shtml
As such, it is easily possible to have a female at the tall end of the height curve, and a
male at the short end of the height curve. The curves for gender overlap, for the most
part, with the peak of each curve slightly off-set. It is easy to say that the average
height is shorter for females than it is for males, but that information is useless when
we examine two individual skeletons.
There are several ways to more accurately determine the gender of a skeleton. One of
them is by examining the pelvis, which can be identified accurately 95% of the time.
Images from http://www.clipart.com, and adapted by Mr. Lazaroff
Original images from http://www.boneclones.com
Circle the Appropriate Answer
Angle > 90 degrees or < 90 degrees
Angle > 90 degrees or < 90 degrees
Sacrum Forward or Backward
Sacrum Forward or Backward
Pelvic Outlet Small or Large
Pelvic Outlet Small or Large
Ilia Close or Spread
Ilia Close or Spread
Female or Male
Female or Male
Another way is to examine the skull. This is still fairly accurate, but not as accurate as
the pelvis. Forensic anthropologists can accurately identify the skull somewhere
between 85 and 90% of the times. This can be complicated by several factors. If a
skull is incomplete, then, of course, there is less to work from. Some of the
distinguishing characteristics, such as larger bone landmarks for muscle attachments
in males, can be easily confused with the landmarks of more athletic females. To put
it simply, since the landmarks are often for the attachment of muscles, the larger the
muscles, or the more one uses the muscles, the larger the landmarks.
Landmarks
Female
Male
Chin
Mastoid Process
Rounded
Square
Small
Large
(Behind Ear)
External Occipital
Protuberance
Small
Large
(Not Prominent)
(Prominent)
General Anatomy
Gracile (i.e., Graceful)
Robust
Receding
Forehead
Vertical
(Careful with the comments .
. .)
Slightly Developed
Prominent
Slightly Developed
Prominent
Sharp
Rounded
Obtuse
Close to 90 degrees
(Back of Skull)
Brow Ridges
(Location of Eyebrows)
Muscle Lines
Orbital Margins
(Edge of Eye Socket)
Angle of Ascending
Ramus
(Back Corner of the Jaw)
Now try to identify the skulls below by gender:
Original images from http://www.boneclones.com
Circle the Appropriate Answer
Chin Rounded or Square
Chin Rounded or Square
Mastoid Process Small or Large
Mastoid Process Small or Large
Occipital Protuberance Small or Large Occipital Protuberance Small or Large
General Anatomy Gracile or Robust
General Anatomy Gracile or Robust
Forehead Vertical or Receding
Forehead Vertical or Receding
Brow Ridges Slight or Prominent
Brow Ridges Slight or Prominent
Muscle Lines Slight or Prominent
Muscle Lines Slight or Prominent
Orbital Margins Sharp or Rounded
Orbital Margins Sharp or Rounded
Angle of Ramus 90 degrees or Obtuse
Angle of Ramus 90 degrees or Obtuse
Gender Female or Male
Gender Female or Male
Now that you have had some practice, what about this lone skull?
Circle the Appropriate Answer
Chin Rounded or Square
Mastoid Process Small or Large
Occipital Protuberance Small or
Large
General Anatomy Gracile or
Robust
Forehead Vertical or Receding
Brow Ridges Slight or Prominent
Muscle Lines Slight or
Prominent
Orbital Margins Sharp or
Rounded
Angle of Ramus 90 degrees or
Obtuse
Gender Female or Male
Original image from http://www.boneclones.com
For more information on "sexing" the skeleton, see the following page:
http://www.uic.edu/classes/osci/osci590/7_07Notes%20for%20Week%207.htm
RACE
There are several features that can be used to determine the race of an individual. In
terms of the skull, a great place to start is the maxillary bone. The left and right
maxillary bones form the roof of the mouth, contain the upper 16 teeth in the adult
(the upper 10 teeth in the child), and form the outline of the nasal cavity (the nasal
cavity itself involves several other bones: ethmoid, inferior nasal conchae, lacrimal,
nasal, sphenoid, and vomer).
The arch of the maxilla can be found in three basic shapes: hyperbolic, parabolic, and
rounded. Each of the the following three races have their own shape: (1) African =
hyperbolic, (2) European = parabolic, and (3) Asian = rounded.
Hyperbola
Parabola
Image from http://www.gapImage from http://www.gapsystem.org/~history/Curves/Hyperbola.html system.org/~history/Curves/Parabola.html
The incisors, as well, differ in their basic shape. The incisors (click HERE to refresh
your memory) fall into two basic categories, based on the shape of the lingual
(tongue) surface of the tooth. These two categories are: (1) shovel-shaped, and (2)
spatulate, or spatula-shaped. As there is more than one race with spatulate incisors,
other indicators are necessary to positively identify race, although this single feature
can be used to eliminate one of the possibilities. Each of the the following three races
have their own shape: (1) African = spatulate , (2) European = spatulate , and (3)
Asian = shovel-shaped.
Based upon both criteria, label the following maxilla according to race:
Original image from http://www.boneclones.com
Circle the Appropriate Answer
Arch Shape
Arch Shape
Arch Shape
Hyperbola, Parabola, or
Hyperbola, Parabola, or Hyperbola, Parabola, or
Rounded
Rounded
Rounded
Incisor Spatulate or ShovelIncisor Spatulate or
Incisor Spatulate or
shaped
Shovel-shaped
Shovel-shaped
RACE African Asian
RACE African Asian
RACE African Asian
Caucasian
Caucasian
Caucasian
In addition to determining gender, there are characteristics of the skull that can be
used to determine the race of an individual. Many of these features are quite subtle,
and require detailed examination of the skull. A couple of features, however, are more
easily seen. For example, in people of African ancestry, the nasal opening is more
flared. Another example is that of the zygomatic arch (or cheek bone), which is angled
more forward in people of Asian ancestry, thus giving the person a slightly more
flattened face.. Unfortunately, a true examination of racial characteristics is not
possible on a worksheet.
Original images from http://www.boneclones.com
African Male Nose
Asian Male Cheek
(Note Flaring)
(Note how it is angled
forward)
Now Compare Examples of Skulls from these three
Races
Asian
African
European
AGE
The idea of age being represented by the skeleton was introduced in the Skeletons as
Forensic Evidence website we looked at earlier. One way we could tell was by
looking at the condition of the bones themselves, with the older bones being more
likely to be arthritic. Examine the bones below, and label which is arthritic (and
therefore older), and which is the younger:
Original image from http://www.boneclones.com
Circle the Appropriate Answer
Arthritic Yes or No
Arthritic Yes or No
Younger or Older
Younger or Older
Another way to determine age is by looking at the development of the sutures:
Images from http://www.clipart.com, and adapted by Mr. Lazaroff
Note, for example, that the adult skull has no remaining suture (called the frontal
suture) in the middle of the Frontal bone. Remember, also, that all the sutures
ultimately become more filled-in ("closed") as we age. Compare the two skulls below
to determine which skull is from an adult, and which is from an adolescent:
Original images from http://www.boneclones.com
Circle the Appropriate Answer
Frontal Suture Present or Absent
Frontal Suture Present or Absent
Other Sutures "Open" or "Closed"
Other Sutures "Open" or "Closed"
Adolescent or Adult
Adolescent or Adult
Can you see the fontanels in the image below? Note how many places in the infant
skeleton are still made of cartilage, which appears blue. The indicates how much of
the skeleton is still developing.
Please note that the pelvis is still divided into the three parts: ilium, ischium, and
pubis; these will ultimately fuse into a single pelvic bone (a.k.a., Os coxa, or
Innominate). Note the many bones in the sternum, which will ultimately fuse into one.
Remember that the total number of bones in the skeleton, 206, is based on an adult
skeleton. The actual number in an infant is much higher!
Please also note that there is a great deal of cartilage at the end of each of the long
bones, an area called the epiphysis (see the image below). (If each end is called the
epiphysis, how do we show one end of the humerus from the other end in the name?
Easy: Proximal epiphysis& Distal epiphysis!) The cartilage at all the epiphyses (pl.)
indicates that a great deal of growth in long bones is actually happening at the ends
(thus making the bones longer. Another way to determine age is to look at the
epiphysis (end) of a long bone (the shape of which should be self-explanatory).
First of all, an x-ray is actually a film negative. When light (Don't forget that x-rays
are a form of light!) hits photographic film, it turns the film black; in making a print
(i.e., making a negative of the negative, which is therefore a positive), the image
printed will look white. The more light, the darker the negative, and the brighter the
developed image. X-rays pass easily through muscle and most organs, but not through
bone; this will make the bones appear lighter in the negative (which works well for
us, as bones are already white!). An x-ray image (radiograph) of a child will reveal a
dark area where the growth plates are still made of cartilage (more x-rays can pass
through cartilage, which is less dense, thus making a dark area); these areas are the
epiphyseal plates. An x-ray radiograph of an adult will reveal a white area where the
growth plates have been turned into bone (fewer x-rays can pass through bone,
which is more dense, thus making a white line); these areas are the epiphyseal lines.
Examine the radiographs below, and determine whether they are from adults or
children:
Images are from
http://www.dartmouth.edu/~anatomy/knee/radiographs/radio3.html
Circle the Appropriate Answer
Epiphyseal Plate or Line
Epiphyseal Plate or Line
Adult or Child
Adult or Child
HEIGHT
Lastly, often a skeleton is incomplete. Despite this, it is still possible to calculate, with
a certain amount of accuracy, the height of a skeleton, even if the calculation is based
upon a single bone! Apart from height, average weight can be calculated based on not
only the general size of the bones, but also by evidence of the weight borne by the
bones. These weight calculations, however, are too complex to demonstrate without
detailed examination of the bones, which obviously cannot be done on a paper
worksheet.
Any of the major bones of the arm or leg can be used to determine height. The major
bones of the arm are the humerus, ulna, and radius. The major bones of the leg are the
femur, tibia, and fibula. The Given that not everyone's arm to leg ratio is exact, height
is usually estimated by using more than one bone, if possible. Granted, a complete
skeleton does not require calculation, but skeletons are not always complete,
especially ancient skeletons. The calculations we will be looking at will be of the
femur, humerus, and radius.
SmartDraw Image adapted by Mr. Lazaroff
In order to calculate the height, in inches, follow the formulas below for each of the
bones. Be sure to indicate height not only in the total number of inches, but in terms
of feet and inches (i.e., a person who is 62 inches is also described as being 5 feet, 2
inches tall, or 5' 2"). NOTE: The calculations, of course, are different when
measurements are in centimeters.
Bone
Formula for calculating Body Height (in inches)
(See
Image)
Female
Male
Height equals (length of femur x 1.94) +
Height equals (length of femur x 1.88) +
32
Height equals (length of humerus x 2.8) + Height equals (length of humerus x 2.9) +
Humerus 28.1
27.8
Radius Height equals (length of radius x 3.3) + 32 Height equals (length of radius x 3.3) + 34
Femur 28.7
In order to calculate the height, in cm, as most of the world does, follow the slightly
different formulas below for each of the bones.
Bone
Formula for calculating Body Height (in cm) . . . EVERYONE!
(See
Image)
Female
Height equals (length of femur x 1.94) +
Male
Height equals (length of femur x 1.88) +
81.3
Height equals (length of humerus x 2.8) + Height equals (length of humerus x 2.9) +
Humerus 71.4
70.6
Femur 72.9
Height equals (length of radius x 3.3) +
Radius 81.3
Height equals (length of radius x 3.3) +
86.4
Now plug in the following numbers into the formula to determine the height to
the
nearest 1/2 inch (expressed both as inches -- x" -- and as feet and inches -- x' +
y") of the deceased:
Gender Bone Length
Female Femur
Male Femur
Calculations
SHOW YOUR WORK!
Height
x"
in
Inches
Multiply
Height
by 2.54 to
x' + y"
get the
(Feet +
Height
Inches)
in cm
17.9"
17.9"
NOTE: The same length is shown to illustrate the different calculations
required for the same measurements, depending on the gender of the deceased.
Female Humerus 11.5"
Male Humerus 11.5"
Female Radius
Male
Radius
9.3"
9.3"
Check Your Work using our Bone Length to Body Height Calculator
Gender Bone Length
Calculations
SHOW YOUR WORK!
Multiply
by
Height
Height
0.3937 to in Feet
in cm
get the & Inches
Height
in inches
Female Femur
Male
Femur
45.5
cm
45.5
cm
NOTE: The same length is shown to illustrate the different calculations
required for the same measurements, depending on the gender of the deceased.
Female Humerus
29.2
cm
Male Humerus
29.2
cm
Female Radius
Male
Radius
23.6
cm
23.6
cm
QUESTIONS:
1. What is the easiest way to determine the gender (using the skeleton) of an
2.
3.
4.
5.
individual, and why?
What is the easiest way to tell (using the skeleton) whether a teenager is lying
about her/his age, and why?
Why can determining gender from a skull be difficult?
Why should a forensic anthropologist use more than one bone (if possible) to
determine the height of an individual?
What other issue is important to question four, especially if there is only one
bone from which to work?