Forensic Anthropology PDF

## Chapter 7: Anthropology Forensic anthropology is the application of theory and methods of anthropology to forensic problems. - Extremely important w/ skeletal remains. - Determine whether skeletal remains are human and whether they have forensic importance. - Need knowledge of osteology (S...

## Chapter 7: Anthropology Forensic anthropology is the application of theory and methods of anthropology to forensic problems. - Extremely important w/ skeletal remains. - Determine whether skeletal remains are human and whether they have forensic importance. - Need knowledge of osteology (Study of bones) and odontology (study of teeth), taphonomy (human form). - Adult skeleton = 205 bones - Children and Infants = up to 405 (due to ossification contects) - Post mortem alterations need to be carefully differentiated from the pre-mortem alterations. - Frequently called to participate in body recovery - Often referred to as forensic archaeology. - Allows to see the vic taphonic context. - Is helpful for interpreting post-mortem processes. ### Biological Profile - Entails studying the remains, while noting characteristics of shape + size that can allow for an estimation of age, sex, population, or ancestry. - Height is estimated by measuring total body length, or by extrapolating long bone lengths. - Goal is to help narrow who the body could be. ### Estimating Age *** - Skeletal development: - Females develop a bit earlier than males. - Teeth: Humans have 2 sets: Deciduous Dentition & Permanent Dentition - Children: 2 incisors, 2 premolars, 1 Canine, 3 molars. *** ### Recovering Remains - Clandestine Grave: when a body is buried in order to hide it. - A grid will be made to present info abt the spatial distribution. - The area is also photographed before any work is done. - Anything (bugs & plants tools) associated with the body is collected. - Ground Penetrating Radars are used. - Remains are moved & documented. - Staging area for evaluation is set & samples are taken of things within several yards of the site. ### Taphonomic Context - The immediate environment and surroundings where the body is found. - The condition of the body can provide clues on how long the body has been there. ### Age Related Changes - Skeleton changes until death. - Ex: osteoporosis - Macroscopic assessment relies on: - Cortical bone (dense outer layer) (thimning or not.) - Trabecular bone (spongy bone) (reduced concentration?) - Remodeling (changes bone shape) ### Pubic Symphysis - When the left & right halves of the pelvis join in the front of the body. ### Determining Sex - Female traits: - Shallow sciatic notch - U-Shaped subpubic angle. ### Disarticulation - Joints are not held w/ soft tissue ### Osteometry - Specialized measurements of the bones are reported as a range. ### Identification - ME's & coroners require positive identification (beyond a doubt). - It can mean: DNA analysis, fingerprints, dental records, x-rays, or unique apparatus. ## Importance of Forensic Anthropology 1. Use of Skeletal Anatomy to Identify remains- provides info about victim - Identify is bone is human or non-human. 2. Human Bones/Teeth are identified and cataloged, observations and measurements are recorded. 3. Biological Profile is made of victim ( Estimated Age, Sex, Stature, Ethnicity,) and evidence of trauma/disease. - Additional Info such as dental records, implants, etc are added also. 4. Detectives review descriptions of local missing persons that are consistent with biological profile. - In 1849, the Webster Trial set standard for Bone Identification Facial Reconstruction Techniques. - It is only possible to identify a skeleton's sex after it has reached adolescence. ## Science of Bone ### Osteoporosis: - Condition where bones have lost too much calcium, suffer from weak bones due to loss of bone density. - Can give a person a hunched appearance. ### Characteristics of Bones #### Bones and Geography - Bones are tested for presence of carbon and strontium to see where a person lived. - Strontium: Naturally Occurring element found dissolved in groundwater. - Different areas have diff levels of strontium and diff isotopes. - Ingestion of Strontium leads to it being deposited in bones and teeth. - Through Comparison of strontium in diff regions, with lvl found in bone and teeth, a person can be possibly found where they lived. - Carbon: - Foods have diff amounts of Carbon 13 and 12 that get absorbed in bone through comparison, they can estimate the location. ### How to Distinguish Males from Females - Adult Female Skeleton tends to be more slender(gracile) than adult male- thicker and more robust. - Male Bones, at the site where muscles and tendons attach, are thicker, leading to more robust. - Determination of sex by skeletal remains can only be done if the body is past puberty. #### Skull: - Male Frontal Bone- Low and Sloping, Female Frontal Bone- Higher and More Rounded. - Males have thicker and pronounced brow ridges compared to females. - Eye Orbitals shape is square and in females, its round. - Mastoid Bone is larger and longer in male than in female. #### Pelvis: - For Women during pregnancy, the cartilage in pubic symphysis softens and allows separation of bones during childbirth and reharden after delivery. - Women Pelvis has scars if they had children. - Scars don't always appear, and can appear in women who have not given birth. - Subpubic Angle: The Angle that is formed just below the pubic symphysis. - Female Pelvis is usually wider, sacrum curved away from body, shorter tailbone(coccyx), larger subpubic angle and a larger pelvic cavity opening than male. ### How to Estimate Age - Estimate Age by examining degree of ossification and wear/tear on bones. - For Child dental remains are more reliable. #### Ossification of Bones: - Forensic Anthropologist examines to note # of bones, degree of ossification, presence/absence of growth plate, degree of wear etc. - Ex: Fusion with the clavicle begins in early 20s and ends at 30. - Ex: Skull has several bones that fuse between ages of 30 and 60. ### Teeth - Pathologists or odontologists can estimate the age of a person from an impression of their teeth. ### Skull Suture Marks: - Form as cartilage has almost replaced the soft cartilaginous areas on skull. - Usually after age 60, the open suture marks fuse and ar fully ossified. - Sagittal Suture— Fuses at age 32 if not closed assume below 29. - Lambdoidal Suture—Starts at age 21, accelerates at age 26, and fuses at age 30. - Squamosal Suture begins fusing after age 60. - Coronal Suture fuses at about age 50. ### Pubic Bone and Sternal Rib Surfaces - The edges of the two public bones surrounding the public symphysis progresses from rough with lots of grooves and ridges, to porous and pitted surface. - The 4th rib that is attached to the sternum have similar changes. ## How to Distinguish Ancestry - Height is derived from Femur, Tibia, Radius, Humerous using a set of known equations. - Mongoloids: Asian or Native Decent - Caucasoid: European - Negroid: African ## Broken Bones, Diseases, Toxic Exposures, and Nutritional Status - Broken bones have evidence of the break and the breaks are usually uneven because the bone is more elastic. - Bones in Advanced Decomposition tend of snap off evenly, lost their elasticity, and are brittle. - Osteoarthritis and Osteoporosis can be seen. - Anemia results in holes in the eye sockets and skull. - Lack of Vitamin D causes rickets, resulting in bowing of legs, thinning of skull, and deformed spine. - In situ: Undistributed where they were found. ## Analysis of Skeletal Remains ### Preliminary Field Observations - It is not always easy to know if an evidence is a human bone fragment or something else - Bone Color- Creamy White to brown w dull luster - Texture- Varies with hard dense compact bone and porous spongy bone ### Standard Procedures for Bone Analysis - The Webster Trial became the standard procedure for identifying skeletal remains ### Skeletal Analysis and Identification #### Comparative Radiography: - Nondestructive imaging of bones with electromagnetic energy. - Useful when identification is impossible due to burns or decomposition. - Ex: x Rays, CT Scans, and MRI. - Cons: Bones are always being remodeled, so antemortem and postmortem images after many years can be hard to compare. #### Nonimaged Records' Comparison: - Medical Notes/records on skeletal/dental conditions, procedures, or implants can be valuable in deciding if remains belong to a specific person. ### DNA Analysis - DNA can be recovered from skeletal and dental remains. - Nuclear DNA can be extracted from bones and teeth and analyzed using STR Profiling - When recovered DNA is compared w DNA of a known biological relative, it can help identify a person. - Mitochondrial DNA can also be used in place of nuclear DNA. - It cant establish individual identity but it can find individuals with common maternal relatives. - Y Chrome STR Analysis can indicate individuals in same parental line. ### Photographic/Video Superimposition - Superimposition is when a image of the skull was superimposed over a photograph/video and compared. ### Craniofacial Reconstruction - Models that "reconstruct" the facial features of an individual so that an approximation of face is produced. - Use tissue depth method that involves building up a clay model. ### Skeletal Trauma Analysis - Analyzing skeletal remains for signs of trauma. #### Antemortem: - Damage to bones long before death. - Ex: Broken Bones/Fractures. - Ex: Defensive Wrist Wounds, other bone injuries such as skull fractures. - Wont show healing and breaks will be clean and not jagged. #### Perimortem: - Shortly before or at time of death. - Ex: Defensive Wrist Wounds, other bone injuries such as skull fractures. #### Postmortem: - After death - Usually caused by environmental factors and will exhibit jagged edges. - Broken Hyoid Bone means someone was strangled, small broken bones in man can indicate defense, Punctures due to sharp or blunt force trauma have distinctive patterns. - Blunt Objects generally create more cracks from site of impact and typically cause more dmg to surface of bone. - GSW has a small entrance wound and a larger, beveled exit wound. ### Human or Animal Bone - If long bones are present, angle at which the joint connects to another bone can help distinguish. - The angle that the femur attaches to the pelvis may indicate whether it was 4 legged or 2 legged. - Thickness of Outer Cortex: - Adult Human its 1/4th the diameter of bone. - Large Mammal its 1/3rd. - Osteons: - In Humans, Osteons are scattered. - In other animals, Osteons are lined in rows. ## Quizlet Terms Not in Book - Bone Atrophy: Waiting/Decreasing in size due to disease, injury, or lack of use. - Bone Hypertrophy: Causes bone to grow abnormally large. - Necrosis: Death of Tissue. ## Some Additional Terms: - 24 bones in vertebrae, 25 bones in the thoracic cage, 4 bones in shoulder, 4 bones in pelvis, 8 bones in legs, 52 bones in feet, 4 bones in forearm, 2 bones in arm. - Cancellous Bone/Spongy Bone: Many Inner Layers of Bone. - Dental Formula (ICPM ): Incisors, Canine, Premolars, Molars. - Dental Formula 2, 1, 2, 3): 2 incisors, 1 canine, 2 premolars, and 3 molars. - Both Dental Formulas are only for one side of mouth. - Osteology (bone ) vs Odontology ( dental). - Taphonomic Assessment: Assessment of condition of dead body in conjunction with the context in which it was found. - Ventral Arc: Linear Arc/Ridge of Bone that develops on front of the pubic bone in females below the pubic symphysis. - Sciatic Notch: Curved Edge of adult pelvis ( wider in females than males). - Simeometer: Instrument used to measure facial flatness - Post Cranial: Part of body apart from the cranium. - Equifinality: Similar Result from two different processes. - Disarticulated: Separation of Bones at Joint. - Plastic Deformation: Change in Shape from serious injry.