Name: Project 1.2.3: Bone Detectives Introduction

Transcription

1 Project 1.2.3: Bone Detectives Introduction Name: When we think of bones, we most often think of the way in which these hard structures support the body, how they work with muscles to produce movement and how they protect our internal organs. But the 206 bones of the human skeleton can also tell a story. The specific structure of your bones reveals information about your gender, your height, your age and even your ethnicity. These biological clues are often the first pieces of evidence scientists look to in identifying the remains of a missing person. Specialists called forensic anthropologists are trained to analyze the secrets locked in a bone s shape and structure and can use this information to help solve crimes, trace human origins, or identify those who have gone missing. In this project, you will assume the role of a forensic anthropologist and complete a detailed examination of skeletal remains. Forensic anthropologists use a combination of quantitative and qualitative measures to predict traits from bone. Through a series of metric measurements and direct observation, you will gather clues about the identity of the remains that have just been unearthed in a local park. Last week, a young couple was out for an early morning run. Stopping to catch a drink, they stumbled upon what appeared to be a human skull. The police arrived at the scene and went on to unearth two skeletons lying side by side. With a huge backlog of missing person cases, the police are looking to you for answers. Who are these people lying forgotten in the park? Can these bones tell their story and finally provide closure to grieving families? In this project, you and your team of forensic anthropologists have been called in to examine the skeletal remains. Through careful observation and measurement of the bones found at the scene, you will provide the local police department information that is vital to identifying these individuals. You will analyze features of bone to determine as much as you can about each person s gender, ethnic origin, age and height. Once you have completed your tasks, you will prepare your findings in a detailed report to the police department. Equipment Computer with Internet access Ward s Sherlock Bones: Identification of Skeletal Remains Kit o Protractor; Metric ruler; Calipers (large and small) o Skeletal remains- skull, pelvis, humerus and femur or tibia Laminated instructions & photographs & Calculator Anatomy in Clay Maniken & Skeletal system graphic organizer Procedure Part I 1. Go to Visible Proofs: Forensic Views of the Body In the section Learning from Bones, complete the visual comparison activities to determine the sex and the ethnic origin of the skulls. Answer the following questions:

2 a. What are three areas that help in determining a male versus a female when looking at the skull? b. What are the four clues that are used to help determine ancestry? c. How can you tell a difference between an exit and entrance wound of a bullet? 2. To learn more about the field of forensic anthropology and the duties of a forensic anthropologist, read the two interviews found at the bottom of the page (Barbian and Sledzick) and answer the following questions. a. What does Lenore Barbian specialize in? b. What does she do as a curator at the National Museum of Health and Medicine? c. In the interview from Paul Sledzick, what does he state is the four ways to identify disaster victims? d. What was Sledzick role during the investigation of the crash of flight 93 in Pennsylvania? e. After reading both articles, what is your definition of a Forensic Anthropologist in your own words? Do NOT give a google definition.

3 3. Before you begin looking a missing skeleton, your team will need to learn & mark additional bones on your Manikens and on your graphic organizers. o The bones listed below are important to Forensic Anthropologist in determining age, sex, race, and height of an individual. Research the following bones and then mark all the bones or bone landmarks on the pictures in this packet. NOTE: Some of these structures may already be labeled on your graphic organizer and manikin. Ischium Illium Coccyx Sacrum Pubis Pubic Symphysis Eye Orbit Nasal Cavity Zygomatic Bone Mandible Maxilla Femur - already labeled on previous graphic organizer Humerus - already labeled on previous graphic organizer Tibia- already labeled on previous graphic organizer

4 Part II 5. Now that you have read about the role of a forensic anthropologist in analyzing skeletal remains, work with a team to analyze the bones from an unearthed skeleton. You will analyze features of bone to determine as much as you can about each person s gender, ethnic origin, age and height. Your team will be assigned Skeleton A, B, or C. Make sure that you are only working on the bones that belong to your assigned skeleton. 6. For each bone, you will be asked to complete both visual comparison exercises as well as metric measurements. Determine which bone you are analyzing and locate the appropriate data tables. NOTE: As you are only looking at four bones, you will not use all of the data tables displayed o Use the laminated Ward s instructions, laminated photographs, and tools at each station to complete the observations or measurements listed for that bone, and determine as much as you can about the person s gender, race and age. NOTE: Not all bones will be used for all three categories. o Work with your group to come to consensus on each trait/measurement. Record your findings in Data Tables. NOTE: Forensic anthropologists use a scaled system when assessing features from bones. For example, when they look at the shape of the eye sockets to help determine gender, they use a 5 point assessment scale, with each gender at an end of the scale. The shape may fall somewhere in the middle. Therefore,

5 looking at multiple features is necessary to make an informed assessment. Think about this process as you evaluate the bones. SEX DETERMINATION The most valuable bones in sex determination are the pelvis and the skull, although the femur, tibia and the humerus provide unique measurements that often assist in determining identity. Once you have determined your result for each trait, circle or highlight male or female. Pelvis Table 1 Trait Result Female Male Sub-Pubic Angle > Pubis Body Width ~ 40 mm mm Greater Sciatic Notch > 68 < 68 Pelvic Cavity Shape Circular and wide, showing mainly coccyx Heart-shaped, showing sacrum and coccyx 7. Why do you think the pelvis is often the first bone forensic anthropologists look to in determining sex from skeletal remains? Skull Table 2 Trait Result Female Male Upper Edge of Eye Sharp Blunt Orbit Shape of Eye Orbit Round Square Zygomatic Process Not expressed beyond external auditory meatus Smooth Expressed beyond external auditory meatus Rough and Bumpy Nuchal Crest (Occipital Bone) External Occipital Generally absent Generally Present Protuberance Frontal Bone Round, globular Low, slanting Mandible Shape Rounded, V-shaped Square, U-shaped Ramus of Mandible Slanting Straight

6 Femur Table 3 Trait Result Female Indeterminate Sex Male Vertical (maximum) < > 44.5 Diameter of Femoral Head Bicondylar Width < >76 Maximum Length < >430 Tibia Table 4 Measurement Result Average Female Average Male Maximum Epiphyseal Breadth of Proximal Tibia Maximum Epiphyseal Breadth of Distal Tibia Humerus Table 5 Trait Result Average Female Average Male Transverse Diameter of Humeral Head Vertical Diameter of Humeral Head Maximum Length Epicondylar Width FINAL SEX DETERMINATION: List reasoning below:

7 RACE DETERMINATION Forensic anthropologists generally use a three-race model to characterize skeletal remains: White (European), Asian and Black (African). The skull is often the most valuable bone in tracing origins, and various measurements around the face reveal information about ancestry and heritage. Skull Nasal width: mm Nasal height: mm Table 6 Trait Result White Asian Black Nasal Index < >.53 Nasal Spine Prominent spine Somewhat Very small spine Nasal silling/guttering Sharp ridge (silling) prominent spine Rounded ridge No ridge (guttering) Prognathism Straight Variable Prognathic Shape of the Orbital Openings Rounded, somewhat square Rounded, somewhat circular Rectangular Use the three skull photographs to calculate the nasal index for each racial group. Compare these values to those listed above and if needed, describe what could account for any inconsistencies. White skull: Nasal width mm Nasal height mm = Nasal index Asian skull: Nasal width mm Nasal height mm = Nasal index Black skull: Nasal width mm Nasal height mm = Nasal index Femur White- fingers can fit under the curvature of the femur Black- fingers cannot fit under the curvature of the femur FINAL RACE DETERMINATION:

8 HEIGHT DETERMINATION The height of the individual is most often determined by examining the lone bones, such as the femur, tibia, or humerus. The accuracy of these calculations is improved if two or more bones are used. Forensic anthropologists have compared bone length to height and have calculated formulas that describe this relationship (broken down by racial group and by gender). Using information you have gathered about the gender and ethnicity of the skeleton, choose the appropriate equations and calculate a possible height range. As there is no listed formula for using the maximum length of the femur to estimate height in an Asian female, use only the equation listed for the other available bone. Record the minimum and maximum value of the calculated height ranges (looking at both bones). Convert the minimum and maximum value to feet and inches and estimate the height range of this individual. Femur Maximum Length of the Femur (MLF) mm = cm Male Regression Formula 2.32 (MLF) ± (MLF) ± 3.80 Caucasoid (White) Mongoloid (Asian) Negroid (Black) 2.10 (MLF) ± 3.91 Table 7 Height Range Female Regression Height Range Formula 2.47 (MLF) ± 3.72 Formula not available 2.28 (MLF) ± 3.41 Tibia Maximum Length of Tibia (MLT) mm = cm Male Regression Formula 2.42 (MLT) ± (MLT) ± 3.27 Caucasoid (White) Mongoloid (Asian) Negroid (Black) 2.19 (MLT) ± 3.91 Table 8 Height Range Female Regression Height Range Formula 2.90 (MLT) ± (MLT) ± (MLT) ± 3.70

9 Humerus Maximum Length of the Humerus (MLH) mm = cm Name: Male Regression Formula 2.89 (MLH) ± (MLH) ± 4.16 Caucasoid (White) Mongoloid (Asian) Negroid (Black) 2.88 (MLH) ± 4.23 Table 9 Height Range Female Regression Height Range Formula 3.36 (MLH) ± (MLH) ± (MLH) ± 4.25 To determine the probable height range of the individual, refer to the height tables you filled in above and record the minimum and maximum value of the calculated height ranges in the space below. Convert each value to feet and inches and show the final height range. FINAL HEIGHT DETERMINATION Minimum value = cm 2.54 = inches = feet inches Maximum value = cm 2.54 = inches = feet inches AGE DETERMINATION Make sure to refer to the photograph of the pelvic bones while completing your analysis. Remember, you are looking for landmarks that occur as a human ages. At birth, humans have about 405 bones. These bones will eventually fuse and form the 206 bones we see in an adult skeleton. Circle your team s conclusion for approximate age range for each bone. Pelvis Table 10 Developmental Occurrence Approximate Age The pubis bone and the ischium are almost completely united by bone. 7-8 (Figure 6) The illium, ishium, and pubis bones are joined together. (Figure 6) The two lowest segments of the sacral vertebrate become joined together. (Figure 8) The illium, ischium, and pubis bones become fully ossified with no evidence of epiphyseal unions (indicated by cartilaginous lines). All segments of the sacrum are united with no evidence of epiphyseal unions

10 Femur Table 11 Developmental Occurrence Approximate Age The greater trochanter first appears. 4 The lesser trochanter first appears The head, greater trochanter, and lesser trochanter first join the shaft. 18 The condyles first join the shaft. 20 Tibia Table 12 Developmental Occurrence Approximate Age The lower epiphysis joins the shaft 18 The upper epiphysis joins the shaft 20 Humerus Table 13 Developmental Occurrence Approximate Age The head and the tuberosities join to become a single large epiphysis. 6 The radial head, trochlea, and external condyle blend and unite with the shaft. The internal condyle unites with the shaft. 18 The upper epiphysis unites with the shaft. 20 FINAL MINIMUM AGE DETERMINATION (range) years 8. The developmental occurrences you used to determine age stopped at age 25. What are other clues a forensic anthropologist may be able to use to determine age if the bones belong to a person over age 25?

11 Part III Name: 9. With your group, prepare a formal case report of your findings. This typed report should be written using terminology that you understand and should include the following headings: o Introduction: Provide a brief case description. Help us visualize what has happened and what you are doing to help solve this case. Be specific about where the bones were found and why you are looking at them. o Summary of Findings: Provide evidence and support for your findings for each trait - sex, ethnic origin, age and height. NOTE: You do not need to list every measurement/observation as evidence. Think about your analysis as a whole and describe how combined data led you to a conclusion. HOWEVER, you must provide important measurements to build your case! Discuss any inconsistencies in the data and address the limitations of these methods in determining identity. o Further Analysis: Read the FBI file on facial reconstruction at Discuss how this technique could be used in this case. Research and report on at least two other tests/types of analysis that can be completed using the bone samples. o What can we learn from these tests? o How can this information be used to identify the missing? o Conclusion: Sum up the case findings and your recommendations for the next steps of the investigation in 1-2 paragraphs.

12 Questions Name: 1. How did your findings compare to the actual data provided by your teacher? What could account for any variation? 2. What is the difference between qualitative and quantitative evidence? Explain how both types of measurements played a role in this activity. 3. In this activity, you were able to analyze skeletal remains in order to determine four particular traits of an individual. In a real life situation, scientists could provide a more detailed description of the individual based on additional information that can be acquired from the bones of this person. Describe at least two other pieces of information you could possibly learn from bone. Make sure to provide a specific example for each piece of information.