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What are forensic lab equiptment required
- tables and benches at least 2m x 1m (room for 1 adult human)
- sink w/hot water and cold running water. heating apparatus and fume hood
- measuring equiptment (calipers etc)
- reference casts and reference books
What are methodological and safety issues? (3)
- 1. Secruity - chain of custody must be maintained, lab must also have restricted access and be alarmed.
- remains must be kept separate from other materials in lab
2. Separation of evadence units
necessary to prevent mizing of bones. only analyse remains ofone individual at a time, one skeleton per table/bench
- 3. Safety in work environment:biological and chemical hazards (vaccination against common diseases and use of fume hood)
- sterilization of remains and body fluids 1% bleach solution and use of protective clothing -gloves, coates, glasses, mask respirators
Preparation of remains (5 steps)
1. examination for soft tissue trauma/post mortem modification
2. bulk soft tissue removal
4. residual soft tissue removal
5. stablizing remains
examination for soft tissue / post mortem modification
removing soft tissue could remove evidence (bone staining usually blood denotes trauma, superficial scratches)
Bulk soft tissue removal
- absolutaly necessary as soft tissue obscures important indicators of age and sex esp. skull and pelvis
- soft tissue inconvinient to handle - messy and greasy
x ray dont give enough info
how to remove soft tissue
use scalpel or tissue scissors and start by removing large muscles aof torso and limbs.
cut tendons and peel tissue away from bone
afte this is done, body cavity opened and internal organs can be removed
what is an alternative way to remove soft tissue?
problems with this
use dermestic beetle larvae - disarticulation and resudual soft tissue removal unnecessary
- - takes weeks extremely
- -smelly process,
- -colony must be maintained
what parts of soft tissue should be kept for further analysis
- skin on finger tips
- tissue for DNA analysis including bone
what entails disarticulation?
articulated bones must be spearated
- remove skull from spine
- remove arms from torso
- remove pelvis from spnal column
- remove legs from pelvis
- separate arms at elbow
- separate legs at knee
- cut through join capsules and tendons
what entails residual tissue removal
remove any remaining muscles, tendons, cartilage by soaking bones in water to soften tissues
simmer bones in water and detergent for several days to remove remaining tissue then degrease and bleach bones
what alternatively can remove remaining soft tissue
antiformalin solution - careful, can disintegrate bones
what is used to degrease bones
soak in benzol for several days
what is used to bleach bones
hydrogen peroxide or potassium hydroxide 8-20 hrs
what entails stablising remains?
- in past - using chemicals such as alvar
- now - not done due to chemical composition of bones which make chemical analysis and dna analysis difficult
what entails reconstruction sorting and reassembly?
broken bones glued back together using non adhesive -water soluble adhesive
- required in cases of commingled remains,
- MNI must be detemined
reassembly place bones for each individual skeleton in anatomical position
what should be checked during reconstruction sortin and reassembly?
- 1. duplication
- 2. consistency in size (similar length, robusticity and rugosity)
- 3. joint surface concurrence (ensure opposite joint surface match e.g. occipial +atlas)
What things must be considered when inventorying remains?
each bones marked with case number
numerical inventory (% of bones present)
state of skeletal preservation (excellent -->very poor)