Forensic Osteology: Bone Identification, Human vs Nonhuman, and Skeletal Analysis

What should be assumed about osteological material until proven otherwise?

It should be treated as medicolegally significant.

What are the four criteria to determine if remains are of forensic significance?

1. Is the material actually bone? 2. Is it human? 3. Did the person die in the last 50 years? 4. Are the remains from a forensic context?

How can you determine if the material is actually bone?

Examine under a microscope for bone structure (fairly compact with some graininess, check chemical composition, and taste the material (bone is porous and will stick to your tongue)

What are the characteristics of human bone under a microscope?

Humans have dense Haversian systems, osteons

What does the term 'taphonomy' refer to?

The study of what happens to bones after death.

How can you distinguish immature human bone (a childs bone) from animal bone?

Immature human bone has unfused epiphyses, while animal bones may have fused ends

- animals have plexiform bone as well as haversian which resembles bricks

What is the significance of bone architecture in forensic identification?

Shape differences due to locomotion (quadrupedalism vs bipedalism) can help distinguish between species.

What visual characteristics indicate contemporary vs. non-contemporary bone?

Contemporary bone is off-white, greasy, smooth, heavy; non-contemporary is discolored, dry, grainy, and fragile.

What body modifications can aid in forensic identification?

Tattoos, piercings, cranial deformation, and dental modifications - can actually date by the material used

What does the condition of internment tell us in forensic contexts?

Body position can indicate whether the body was carefully placed or simply discarded.

What are examples of non-forensic contexts for human remains?

Disturbed legal burials, war trophies, and teaching or anatomical material.

What is the composition of bone?

75% inorganic (hydroxyapatite) and 25% organic (primarily water and collagen).

What are the five biological functions of the skeleton?

1. Red blood cell production 2. Mineral storage 3. Movement 4. Protection of organs 5. Structure/Support.

What is the diaphysis of a long bone?

The shaft of the bone.

What is the epiphysis of a long bone?

The ends of the bone.

What is the metaphysis in long bone anatomy?

The area where the epiphyseal growth plate was located.

What is the role of articular cartilage in bones?

It provides cushioning between bone ends.

What is the periosteum?

A sheath of connective tissue that covers the outside of a long bone.

What is the medullary cavity?

The hollow center of a long bone.

What is the nutrient foramen?

A nutrient 'hole' located mid-shaft where blood vessels and nerves enter the bone.

What are the three layers of the skull vault?

1. Outer table (compact bone) 2. Diploe (marrow space) 3. Inner table.

What is the diploe in the context of skull anatomy?

The spongy texture of the marrow space that absorbs shock.

What is fiber (woven) bone?

Quickly deposited, disorganized, immature bone that forms during bone repair.

What characterizes lamellar bone?

Organized, layered, and mineralized bone deposited parallel to the long axis.

What is compact (cortical) bone?

The strong outer layer of bone that is compacted for strength yet flexible due to collagen.

What is spongy (trabecular) bone?

A lattice work of thin bone strands that absorbs and distributes stress, filled with red marrow.

What are osteoprogenitor cells?

Bone precursor cells derived from mesenchyme that differentiate into osteoblasts.

What is the function of osteoblasts?

Bone-forming cells that secrete unmineralized bone (osteons) and can become osteocytes.

What are osteocytes?

Mature osteoblasts surrounded by bone, involved in maintenance and mineralization.

What is the role of osteoclasts?

Large, multinucleated cells that degrade bone tissue and are involved in bone remodeling.

What are the 7 steps of endochondral ossification?

1. Hyaline cartilage model forms (rough shape of what bone should look like). 2. Perichondrium ossifies and forms a periosteal bone collar. 3. Periosteal bud delivers VAN and osteoblasts through nutrient foramen. 4. Osteoblasts replace cartilage with spongy bone forming a primary ossification center. 5. Secondary ossification centers appear in the epiphysis. 6. Ossification continues from the center towards bone ends. 7. Appositional growth (width) occurs from osteoblast + clast activity.

What is bone remodeling?

The process of bone renewal in response to mechanical or pathological stress.

What occurs during the activation phase of remodeling?

Bone lining cells withdraw and osteoclasts form.

What happens during the resorption phase of remodeling?

Osteoclasts reabsorb bone within the cutting zone and advance along long axis of bone

What is the reversal phase in bone remodeling?

Start of the repair process where osteoclasts die, macrophage like cells polish resorption pit laying down new bone, leaving a visible reversal line

What is the formation phase of remodeling?

Osteoblasts are attracted to the site and secrete osteoid (unmineralized bone goo)

What is the mineralization phase in bone remodeling?

Trapped osteoblasts become osteocytes and begin mineralization of the bone.

What is quiescence in the context of bone remodeling?

Osteoblasts flatten out and become bone lining cells. (takes months)

How many bones are in the adult human skeleton?

Approximately 206 bones.

What are the two main divisions of the skeleton?

Axial and appendicular skeleton.

What does the axial skeleton consist of?

Cranium, vertebrae, and rib cage.

What are the anatomical terms for 'up' and 'down'?

Superior (up) and inferior (down).

What is the function of the mandible?

It is the jawbone that holds the lower teeth.

What are the components of the sternum?

Manubrium, sternal body, and xiphoid process.

What are the types of vertebrae in the human spine?

Cervical (7), thoracic (12), lumbar (5), sacral (5), and coccyx (3-5).

What bones make up the pelvis?

Two os coxa and the sacrum.

What are the bones of the upper arm?

Humerus.

What bones are found in the lower leg?

Tibia and fibula.