Forensic science chap 6

Explain what forensic anthropology is and why is it used

It is the use of skeletal anatomy to identify remains. It is used in cases of severely burned bodies, advanced decomposition, victims of mass disasters, or any situation where the body is not intact enough for a standard autopsy.

It also helps determine the victim’s age, sex, ancestral origin. 

What is the first thing a forensic anthropologist must determine?

Whether the recovered remains are human. If so, each bone and tooth is identified and catalogued. 

What are bones made of, and which part remains after decomposition?

Bones are made of living cells and tissues covered by a hard calcium and phosphate matrix. The inorganic matrix remains after decomposition. 

Describe the structure of a long bone (e.g., femur, tibia).

A long bone has two ends called epiphyses (or caps) and a middle part called the diaphysis (or shaft).

Epiphyses and diaphysis are fused in adults, but not in infants and adolescents. 

what is the importance of growth plates in anthropology?

Growth plates are areas of cartilage between the epiphyses and diaphysis that are actively growing and allow the bones to elongate. The complete fusion of bones is characteristics of adulthood, so the timeline of their fusion into solid bone helps determine the age of a victim.

What is the most reliable skeletal area for determining the sex of an adult, and why?

The pelvis. It is the most reliable because its structure is adapted for childbirth in females, leading to distinct differences.

Compare the male and female pelvis

• Female: Wider,  the sacrum is curved more away from the body, the tailbone is shorter, the subpubic angle is larger and the pelvic cavity opening is bigger. 

• Male: Narrower, subpubic angle smaller, smaller pelvic cavity (more heart-shaped).

What are the key differences between a male and female skull?

• Frontal Bone: Male is low and sloping; female is higher and more rounded.

• Eye Orbits: Male are more square than those of females

• Jaw: Male lower jaw forms an angle closer to 90 degrees.

• Occipital Protuberance (back of skull): Larger in males.

These characteristics alone are not reliable enough for sex identification

How can a skeleton be used to estimate age in a young person versus an older person?

By examining the fusion of growth plates in bones. In adulthood the growth plates disappear (bones are fused). Therefore, when bones are fused you are older and when they are not you are younger. You can also observe signs of aging like bones becoming more fragile, and showing signs of diseases.

What parts of the skull are used to estimate ancestral origin?

The shape of the eye sockets, the shape of nasal cavity, the nasal index (width/height of nasal opening), and the degree of prognathism (jaw projection).

Why is determining ancestral origin from bones challenging?

Because individuals often have complex and mixed ancestral backgrounds, and there is significant variation within any given population.

How is height estimated from skeletal remains?

By measuring long bones (like the femur or humerus). They use mathematical formulas to calculate the height of an individual from one of the long bones. Formulas vary according to sex and ancestral origin.

What is the main goal of skeletal trauma analysis?

To distinguish between damage to bones that occurred before death (ante-mortem) and damage that occurred after death (post-mortem).

What is the key indicator that a bone fracture happened before death (ante-mortem) or after death (post-mortem)?

The living bone is stronger and more flexible than a dried bone, so when the individual is living the bones will break differently than those broken in the post-mortem period.

If injury occurred in life, a process of healing will begin. If injury was the result of the death, no healing will have occurred.

How does the examination of bone damage help point out the type of weapon that was used to cause it (blunt-force trauma, sharp-force trauma, gunshot wound)?

Gunshot wound produce smaller entrance wound and a larger exit wound

Blunt-forced objects create more cracks radiating from the site of impact, and they cause more damage to the surface of the bones.

Sharp-Force creates clean, linear cuts and little to no radiating fractures.