The Access Excellence Periodic Tableau

Whose Skeleton is in Your Closet?

Modified by April Sims from "Bring Your Skeleton to Life" by Richard A. Borst, The Science Teacher, April 1986, pg.42-46.

April Sims
Cooper High School
Abilene, TX


Type of entry:

Lesson/class activity

Type of activity:

Hands-on activity

Target audience:

Biology, Advanced/AP Biology, Anatomy and Physiology, Integrated Science (3,4)

Background information:

This activity helps make your study of the human skeleton much more interesting by determining it's race, sex, stature when alive and the age at time of death. The science department skeleton was a 15 year-old Australian Aborigine male. Even though most of the skeletons today are plastic, they were cast from a real one. The hard part is finding out what the true answer was. The best way is to contact the manufacturer when purchasing, but if you can't then assume what most of the students come up with (along with your opinion) is the correct answer.

This activity will challenge your Biology students and mildly challenge advanced or AP students. A great lesson in metrics and anatomy with very little advance preparation needed. It can be accomplished in a 90 minute period or 2 -45 min. periods. Students need to learn how to measure with calipers and know the location of certain parts of the skeleton (occipital region, frontal region, mandible, sacral region, femur w/ epiphysis, oblique length of femur and trochanteric oblique length of femur). Note: Criteria used to determine age is the presence of cartilage between the head, or epiphysis, of a long bone and the shaft. Look where the ends of the femur has starting fusing or is already fused, there should be a distinct jagged line. You can use straight edge rulers but they are not near as accurate because of the curvature of the skeleton.

If you don't already have calipers, you can try a compass, drawing instruments or a tape measure. Hint: check with the physics teacher for calipers. You can even take string, mark at the appropriate place and then measure against a straight edge meter stick. Or you can mark the measurements on the string first and use it as a ruler itself. The only preparation that I had to do was Xerox the instructions, obtain the measuring devices and take apart the skeleton (they have screws and bolts, just remember how to put him/her back together). I completely separated both femur(s) from all other parts and took off the pelvis so the students could measure the sacral area. You can do this lab with all the parts still attached but I found it much easier to separate the pieces so everyone is not crowded around one area.

Note: Even though the teeth are commonly used to determine age they cannot be used because companies usually replace worn teeth with perfect adult ones.

Abstract of Activity:

Archeologists make measurements on a skeleton to determine sex, age, race and stature of skeletons they discover. They can also determine what caused the death and other medical problems they might have had during their life. These complex methods are too sophisticated for high school students but are able to achieve similar results with practice, good technique and simpler methods.

Most students are curious about who the skeleton was and it makes the plastic cast more realistic. This will be a lab they will remember and talk to others about.


Lesson/activity:

Materials needed:

Note: Sex can be determined by looking at cranial features, looking at the pelvis area (narrow or broad) but the most accurate determination comes from measuring certain parts of the femur. Have the students measure both the right and left femur because some skeletons are put together from several different people.


Skeleton Lab Report

Determine the sex of the individual by looking at the cranium. The frontal profile of a male will have a more pronounced brow than a female. The mandible of a male will be more square with a cleft and a females will be V shaped without a cleft in the chin. Now look at the occipital profile the male will come out with a sharper point than a female profile because of the need for attaching stronger neck muscles. Make a check in the male and female column depending on your observations.

CraniumMaleFemale
Frontal Profile

Mandible

Occipital Profile

Now make further measurements of the femur before you decide the sex (to be sure). The head of the femur is the ball-shaped end. The trochanteric oblique length is measured from the end of the smaller knob below the head all the way to the other end of the femur.

Diameter of the head of the femur _________________mm

Trochanteric oblique length of femur_______________mm

Now compare these measurements with the chart that follows. (Remember to take your measurements in millimeters.)

MeasurementsFemaleProbably
Female
Indefinite
sex
Probably
male
Male
Diameter of
head of femur
<41.541.5 to 43.543.5 to 44.544.5 to 45.5>45.5
Trochanteric
oblique
length
<390390 to 405405 to 430430 to 450>450

Sex of the skeleton__________________

Now determine the Race of the skeleton by measuring the Sacral Anterior Breadth (the distance across the sacrum at the widest point) and the Sacral Anterior Height ( the height of the sacrum from bottom tip to the middle point of the top, note this is not a measurement of the tallest point). Now divide the sacral anterior breadth by the sacral anterior height and multiply by 100 to come up with the sacral index.

Sacral anterior breadth__________mm
Sacral anterior height___________mm

Sacral index = sacral anterior breadth X 100/divided by sacral anterior height =  mm

(show all calculations for credit and check the following chart)

RaceMaleFemale
Australian Aborigines100.2110.0
Andamenese 94.8103.4
Egyptians 94.3 99.1
Europeans102.9112.4
Japanese101.5107.1
African 91.4103.6

Race of skeleton_____________________ ( you can also determine race by laying the femur down on the table with the touching the table and seeing if you can fit your whole hand, knuckles and all, underneath the curvature of the femur. Caucasian femur curvature will allow you to fit your hand underneath. Negroid will not. Note: this method will only allow you to eliminate one race or the other.)

Determine how tall the skeleton was using the formula in the following chart. Use oblique length of the femur (the longest possible length of the femur).

Mongoloid2.15 X (oblique length of femur) + 72.57
Negroid2.10 X (oblique length of femur) + 72.22
Caucasian2.32 X (oblique length of femur) + 65.53

Mongoloid are the races that aren't Caucasian or Negriod.

Height of skeleton _____________________cm (show calculations)

Determine the age at time of death using the following chart. Measure the femur without the epiphysis. ____________years

Evaluation:

Ten points for every bold answer, ten points for the amount of participation in lab groups.

Additional idea:

Students can pretend they are forensic pathologists trying to solve a crime. Each lab group is given only part of the skeleton and have to identify it correctly and present their findings to the rest of the class (pathologists). It would be great if you could come up with enough skeletons to give different groups, different skeletons.


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