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Smithsonian National Museum of Natural History
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Bone Biographies

 

How Bone Biographies
"Get Written"

 
How Bone Biographers Make the ID

Many things can leave marks on or in bones. Evidence of disease or injury (trauma) in a skeleton can help identify the deceased. It can also tell us about a person's general health in life, or
the cause of death. Postmortem marks (left on bones after death) can explain events surrounding that person's death and burial.

 

underdeveloped bones of a 16-year-old bedridden male
Underdeveloped bones of a bedridden male. Image courtesy of: Smithsonian Institution

Activity and Use

Bones change size and shape in response to forces placed on them. Repetitive, heavy use of certain muscles can affect the bones to which they are attached. The bone may thicken, modify in shape, or become roughened where the muscles connect. Similarly, inactivity can cause bone loss, or atrophy — as pictured at left.

Some occupations and habits modify skeletons. The bones of body builders show well-developed ridges where muscles attach. The hips and knees of runners may develop joint deterioration. The right arm bones of someone who is right-handed may be larger than the left. 

Disease

Illnesses that affect the skeleton tend to be chronic conditions. Diseased bone forms abnormally or loses tissue, leaving holes or lesions. Diseases in bone are identified through visual and x-ray examination. Techniques under development identify diseases in bone through molecular analysis.

Upper jaw bone with enamel pits showing heavy wear.
Upper jaw bone with enamel pits showing heavy wear. Image courtesy of: Smithsonian Institution

Diet and Nutrition

Diet has a direct impact on the skeleton. A diet with sufficient nutrients, especially calcium, phosphorus, and vitamin D, is required to build strong bones and teeth. Nutrient deficiencies result in weak or abnormally formed bones. Bones and teeth of individuals lacking good nutrition can be identified visually and by x-ray.

Trauma

Bone may break due to accidental or intentional injury. If a break happens during life (antemortem), the bone can heal or repair itself. At (perimortem) or after death (postmortem), no healing occurs. "Dry" or old bone breaks differently than "fresh" bone.

left femur repaired surgically
Left femur with metal rod implanted to stabilize a fracture, which failed to unite despite bone remodeling (formation of new bone tissue). Image courtesy of: Smithsonian Institution

Most skeletal injuries are visible upon gross examination. X-rays may be needed to help interpret healed or perimortem trauma, including gunshot wounds.

Click here to learn more about how
trauma contributes to bone biographies

Surgical Intervention

Surgical wires, rods, plates, screws, and orthopedic implants are lasting markers for identification. Many medical devices carry model or serial numbers that can be traced to specific medical procedures and patient records.

Postmortem Damage

Some bone modifications happen after death. Investigators have to distinguish perimortem trauma from postmortem changes, such as animal damage, burns, cremation, or coffin erosion.

evidence of postmortem damage by animals
Human bones with postmortem damage due to gnawing by animals. Image courtesy of: Smithsonian Institution

 

 

 

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