Forensic_Nx_for_Shel..

Jodie Gerdin DVM
Dept. of Biomedical Sciences
[email protected]
Overview
 Components of a good forensic Nx
 History, Photos, Written Report, Histo, DACVPs
 Nx goals: Case
 Trauma
 Gunshot wounds
 Emaciation
 Burns
 Drowning
 Asphyxiation
types
The Basic Necropsy
 The
Necropsy Book by King, Dodd, & Ross
 C.L.Davis Foundation $40
 http://store.cldavis.org
 Basic necropsy technique
 Covers non-lesions & artifacts
 Brief & to the point
 Natural disease only
 B&W illustrations; no photos
Before you necropsy…
 Obtain
as much info as possible
 Witness statements, police report, CSI
 Critical
to lesion interpretation:
 Postmortem interval
○ Estimate: Last seen alive  Found dead
 Euthanized or Died
 Body handling since death
○ Fridge? Freezer? Neither?
Before you necropsy…
 The
fresher the better, but…
necropsy as soon as rational
 Can’t re-do a Nx!
 It will still be dead later!
 Allow
1- 4 hr to complete the
necropsy
 Freezing is better than rotting
 Freezing always better than room temp
 Fridge <4 days, or consider freezing
Documenting the Nx: Photos
 Unique
case #, Date, & Ruler
 Exception: close-ups of small lesions
situ, far away, close up, different angles
 Avoid using the flash
 Digital camera with autofocus
 √ pictures you take them (big view screen)
 Before & after pictures
 Archive originals &/or copy to CD
 In
 Take
more than you think you’ll need
http://web.ncf.ca/jim/scale/
ABFO #2 
The Necropsy Report
 No
single “right” format
 Be consistent & thorough
 3 Essential Parts:
1. Gross Description
2. Cause of Death
3. Case Summary
Gross Description
 Describe
the changes observed
 Color, shape, texture, consistency,
appearance on section, smell
 Measure: metric system (cm/ mLs), 3D!
 Specific anatomic location
& proper terminology
 Check photos when
writing description
Gross Description
 Description
never changes;
interpretation can!
 Ex: The lungs are heavy, rubbery, diffusely
dark red, & ooze red-tinged translucent fluid
on section (pulmonary edema).
Gross Description
 Description
never changes;
interpretation can!
 Ex: The lungs are heavy, rubbery, diffusely
dark red, & ooze red-tinged translucent fluid
on section (pulmonary edema).
 Description
 Interpretation
 You don’t have to interpret changes in the
gross description; interpretations may be
made in the case summary.
Cause of Death
 The
event that initiated the chain of
events that led to death
 Ex: Gunshot wound, Bite wounds, Parvo virus
 NOT: Respiratory arrest, Sepsis, DIC
 Explicitly state the CoD
 “Cause of Death: Unknown”
Cause of Death
 If
euthanized, must be listed 1st as CoD
 Euthanasia as defined by AVMA
 +/-
injures/ illness that prompted euthanasia
 Ex: “Cause of Death: Euthanasia due to right
femoral fracture”
 “per
history” if you didn’t euthanize
Case Summary
 Interpretation
of gross lesions & all
other tests
 Tie together findings / what it all means
 Degree & duration of pain & suffering
 Use layman’s terms
 Judge & jury focus on
this part of the report
The Necropsy Report
 A bad
report can undo an entire investigation
 Write gross description soon after the Nx
 Use photos to write descriptions
 Take your time with CoD & Comments
 Lawyers
introduce doubt about competence
using typos; much
harder to fight medical
conclusions
 Proofread before
finalizing!
Working with a DACVP
 Find
a pathologist you can talk to
 Ask questions
 Before submission
○ Nx photos available?
 On submission form
 After you receive report
 Keep
in mind
 DACVPs not formally trained in forensic path &
may not be interested in forensic cases
 DACVPs may not have clinical experience
Histopathology
 Why submit?
 No significant findings on necropsy
 Substantiate necropsy findings
 Establish vitality, & chronicity / timeline
 “Mystery” lesions
 Refute / support statements by the accused
 Still
not sure?
 Collect, formalin fix, & store
○ 5 -7 days formalin  drain  store tissues in ziplock
 Ask a pathologist!
Histopathology
Collect 1 of everything
 Prioritize tissues:

 “Definitely” tissue: submit for histo
 “Maybe” tissue: don’t submit; might be needed later
No thicker
than 1 cm

 Except brain:
fix whole for
5 days
Body Presentation
 ID-ing
features
 Species, Breed / Type
 Sex
 Coat color & white marks
 Age: neonate, adult, geriatric
 Etc: Ear tip, microchip, tattoo
 Items
accompanying body
 Photo:
RLat, LLat, dorsal, ventral, & face
The External Exam

The most important part = Physical Exam
 Trauma extends from outside  in
 Evidence on the outside
BCS: X / Y (Purina, Tufts, etc)
 Hair coat quality
 Oral cavity & Nails / Claws

 Defense wounds
 Emaciation cases
Wounds, scars: pictures before & after shaving
 Don’t forget: Anus, vagina, mammary glands,
uterus (pregnant?), penis, scrotum

Trauma
Goal: Document extent of injuries
 Skin
the body
 Measure hematomas / ecchymoses
 Suspect
pneumothorax?
 Puncture diaphragm
“Woosh” & collapse with Neg pressure
 Does not work on prev frozen bodies
 Examine
the brain
 Injury hidden by skin & skull
 Oscillating “cast” saw
Trauma
 Blunt
abdominal trauma
 Liver, splenic fractures common
 “Real” pre-mortem hemoabdomen
○ Fluid is thick, with BLOOD CLOTS
 Artifact of freeze-thaw or autolysis
○ Watery blood-tinged fluid; NO BLOOD
CLOTS

Dr. John King DACVP: Exsanguination results
in ecchymoses on the visceral surface of the
diaphragm. WARNING: Not studied / unproven!
Photo
courtesy
ASPCA
Photo
courtesy
ASPCA
Gun Shot Wounds
Goals: Find entrance & exit wounds &
projectile; Document damage in between
 2V
Rads essential
 Documentation; Helps find projectile
 Lat only OK for survey; 2v for lesions/ projectiles
 Do
NOT handle projectile w/ metal
 Metal-on-metal ruins ballistic pattern
 Wash & place in paper envelope
Entrance wound
~Smaller
 Smooth-edged
circle or oval; beveling
 Peripheral abrasion

Exit wound
~Larger
 Oval / irregular shape
 Edges irregular
 No abrasion

Arrow wounds
May resemble a cut / stab or laceration
 Wounds: Entrance wound smaller than exit
 Hair at entry wound edge is cut
 Wounds may be impressive (big)!

http://img.photobucket.com/albums/v645/tracerace/Scotts/DSC05673.jpg
http://img.photobucket.com/albums/v645/tracerace/Scotts/DSC00313.jpg
http://i27.photobucket.com/albums/c181/Savage7mm/100_0824.jpg
Emaciation (Starvation)
 Emaciation
= the state of the body
 Starvation implies withholding of food
 Nx cannot prove withholding of food
 But it can rule out natural disease
 Investigation
key!
 Food & feces around?
 Receipts for food?
Emaciation (Starvation)
Goals: Document condition; Rule in/out disease
 Condition of teeth, oral cavity, & GI
 Presence & amount of fat in
 Peri-renal area; Coronary groove; Bone marrow
 Photograph,
collect & save GI contents if any
 Parasitology: Feces or SI & LI loops
 Liver
weight: K9= 1.5–5.9% BW, Cats= 2.5%
 Purdue: Fat % analysis on whole, intact femur
 Ideal for skeletonized remains
Examine bone marrow
at center of long bone
Normal, fatty
marrow
Serous atrophy
of fat; jelly-like
Photo: Michigan DNR Wildlife Dz. Manual
Burns
Goals: Prove vitality, √ for accelerants
 Impossible
to prove death d/t burns
 Soot in airway proves vital exposure to smoke
 Remove pluck; examine in clean area
 Avoid cross-contamination w/ soot from body
 Histology
on airway, lung, & skin burns
 Animals set on fire using accelerants
 Put skin/ fur samples in metal container ASAP!
Photo courtesy ASPCA
Drowning
“Wet” drowning <-----------------> “Dry” drowning
Inhale H20 into lungs
Inspiration against closed
glottis pulmonary edema
Nx goal: Demonstrate aspiration of H2O
Lungs may look grossly normal
 Check for H2O in stomach

 Swallowed H2O supports drowning

Histopathology? Definitely!
 Foreign material in lungs
Tracheal Foam = Artifact 99% of the time
Strangulation

Compression of the neck
CO2 death
↓ in blood O2 & ↑ in
Nx goal: Substantiate (if possible)
 May
be few, if any, post-mortem lesions
 Might leave bruises around larynx
 Might fracture hyoid bones
 May cause scleral petechiae / retrobulbar bleeding
 NOTE: Scleral petechiae ≠ strangulation
Photo courtesy ASPCA
Photo courtesy ASPCA
Questions?
Thanks to Dr. Sean P. McDonough DVM,
DACVP, PhD, Mentor Extraordinaire