Postmortem Changes to Bone

What are the three primary processes that cause postmortem changes?

Dismemberment, Taphonomy, and Fire.

What are some reasons for dismemberment?

To impede identification, show lack of respect or hatred for the decedent, or for easier transport/hiding.

What are the two types of dismemberment?

Localized dismemberments and Generalized dismemberments.

What types of saws are categorized based on function?

Crosscut saws and Rip saws.

What are the three types of marks caused by saws on bone?

Superficial false start, False start kerfs, and Sectioned bone cuts.

What do fine striations on bone indicate?

The type of saw used, with variations indicating different teeth sizes and saw types.

What is TPI and PPI in relation to saws?

TPI stands for teeth per inch, and PPI stands for points per inch.

How can the direction of saw cuts be determined?

From the direction of saw progress and saw stroke.

What effects can animal scavenging have on bones?

Animals can scatter skeletons, break bones, and remove bone segments.

Which animals are typically responsible for the most postmortem changes?

Carnivores, such as dogs and coyotes.

What types of marks do carnivores leave on bones?

Punctures, Pits, Scoring, and Furrows.

What is the significance of gnawing patterns left by animals?

They can help differentiate between scavenging and dismemberment.

What types of damage do rodents typically cause to bones?

They leave flat, square, parallel grooves and usually do not consume much soft tissue.

What are the signs of weathering on bones?

Cracks on the cortex, peeling and flaking, bone warping, and bone bleaching.

What are the primary effects of burial damage on bones?

Cracking and warping, as well as erosion of cortical bone.

What are the three phases of water damage during fluvial transport?

1. Body movement from the initial point, 2. Putrefaction, 3. Intermixing and movement of individual bones.

Crosscut saws

Cut against the grain

Rip saws

Cut with the grain

Fine striations

Small teeth

Deeper striations

Larger teeth

Regular striations

Power saw

Irregular striations

Handsaw

Rough kerf floor

Fewer teeth

Smooth kerf floor

More teeth