Forensic Pathology Chapter 1 - Introduction to Forensic Autopsy

Autopsy (post-mortem examination)

a specialized surgical procedure used to determine the cause and manner of death

Clinical/academic autopsy

the medical attendants, with consent, seek to learn the extent of the disease for which they were treating the deceased patient

Medico-legal/forensic autopsy

performed on the instructions of the legal authority responsible for the investigation of sudden, suspicious, obscure, unnatural, or criminal deaths

Cause of death

the specific disease or injury that initiated the lethal chain of events

Mechanism of death

the direct physiological or biochemical failure of a body system that leads to death

Mode of death

the abnormal physiological state of an individual at the time of death

Manner of death

a legal determination of how the death occurred

Manners of death

natural, accidental, suicide, homicide, undetermined

Temperature to keep bodies in the morgue

4 degrees C when keeping bodies in the fridge for a short period of time

is the recommended temperature for keeping bodies in the morgue for long-term storage to avoid decomposition

-20 degrees Celsius 

Objectives of an autopsy

1. to make a positive identification of the body and to assess the size, physique and nourishment

2. to determine the cause of death, or in a newborn, whether live birth occurred

3. to determine the mode of dying and time of death, where necessary and possible

4. to demonstrate all external and internal abnormalities, malformations, and diseases

5. to detect, describe and measure any external and internal injuries

Objectives of an autopsy continued

6. to obtain samples for analysis, microbiological and histological examination, and any other necessary investigations

7. to retain relevant organs and tissues as evidence

8. to obtains photographs and video for evidential and teaching use

9. to provide a full written report of the autopsy findings

10. to offer an expert interpretation of those findings

11. to restore the body to the best possible cosmetic condition before release to relatives

Scene equipment

waterproof apron and rubber gloves

thermometer, syringes and needles, sterile swabs

autopsy dissection set, including handsaw

cutting needles and twine for body closure

swabs and containers for blood and body fluids

formalin jars for histological samples

plastic bags, envelopes, paper, spare pen and pencil

printed body charts for recording external injuries

hand lens, electric torch, mini-tape recorder

camera

How is time since death determined?

measuring internal body temperature either from the liver or rectum using a rectal thermometer

Normal body temperature and cooling after death 

normally body temp is at 37 degrees C and cools for about one degree per hour until room temp

How are bodies transported?

body bags are used to transfer the body from the scene to the morgue

How are bodily fluids detected?

bodily fluids are detected using ALS (alternate light source)

What should a pathologist do before starting any examinations?

the body must be correctly identified

What should the body be tested for before examination?

HIV and hepatitis

can be in the blood at room temperature for 2 months

External Examination

clothes and any belongings are removed

any external conditions are noted and documented

age is determined as well as race

must note EVERY feature of the body

body length is measured (heel to crown)

body weight for children is measured (not too common in adults)

state cleanliness and personal hygiene

note skin color

injuries must be recorded (body diagram)

Color changes of body during death

pink or brownish patches over large joints may indicate hypothermia

brownish hue of methemoglobinemia in some poisonings

bronze speckling of clostridial septicemia

dark red of cyanide

cherry-pink coloration of carboxyhemoglobin (CO poisoning, most common)

Internal Examination - incision shapes

I-shaped incision -straight line incision extending from the chin to the symphysis pubis

Y-shaped incision - behind each ear and continue down into a Y shape (most common)

U-shaped incision - clavicle to clavicle then continued down

Deflection of the skull/face

incision made from behind one ear and around skull to connect to other ear

when looking for blunt force trauma to the face/skull, bruising/fractures

DO NOT SHAVE HAIR

Exposing body cavities

during internal examination, skin, subcutaneous tissues, and fat are flayed off laterally to expose internal organs

to expose the body cavities, the sternum and ribs are removed by rib shears/cutters or saw

What does the thoracic cage do?

protects the lungs and heart

Ribs of the body

true ribs - 1-7 attach directly to the sternum via their own costal cartilage

false ribs - 8-12 either connect indirectly to the sternum via the cartilage of the rib above or not at all

floating ribs - 11-12 not connected to the sternum at all

Thoracic cavity anatomy

underneath right side of diaphragm is the liver - the liver is important for measuring toxin levels in the body

underneath left side of diaphragm is the spleen - spleen is hard and can't take blunt force trauma, can live without a spleen

What is a pneumothorax?

a collapsed lung

2 types of pneumothorax

simple - involves air in the pleural cavity that stops accumulating

tension - a life-threatening emergency where air continues to enter the pleural cavity (treat with chest tube)

On an X-ray…

air appears dark

tissues appear opaque

What is the greater omentum?

a lipid layer under the stomach that stores fat

Gallbladder

attached to the liver that takes in specific enzymes and releases them to improve digestion

Which tube comes first?

the trachea comes first then the esophagus

Where is blood stored after death?

in the veins

Why is the vitreous humour fluid collected

The removal of vitreous humour and cerebrospinal fluid may be required for toxicology or for attempts at estimated the time since death by the potassium content

How is the skull cut during autopsy

At an angle

3 layers to the brain

Dura matter (outermost layer)

Arachnoid matter

Pia matter (innermost layer)

4 arteries arising from the arch of aorta

2 left and 2 right

Right - vetrebral artery and carotid artery

Lung lobes

Right lung has 3 lobes

Left lung has 2 lobes

What is formalin used for?

Chemical used to preserve an organ but only the structure not the function (formalin fixation)

What is the pericardium

the membrane that covers the heart

What feeds blood to the heart muscles

Coronary arteries

What is the average heart rate in adults

60 - 100 bpm

<60 bpm - bradycardia

<100 bpm - tachycardia

What structure separates the 2 ventricles of the heart

Septum

Which side of the heart has more muscle

the left side

Heart mass of adults

374 g heart mass for males

285 g heart mass for females

What is a blood culture?

A sample of the blood taken from the femoral vein that is taken when an infection is suspected

What is histology?

The study of tissues

Histology samples are very thin in order for light to pass through under the microscope

What histological samples are taken during autopsy?

Liver, spleen, kidney, heart, lung, thyroid, adrenal, pancreas, muscle and brain as a minimum

What is autopsy radiology used for?

Generally used in relation to child abuse, gunshot wounds, identification, and dentistry

When is radiology done during an autopsy?

After the external examination but before internal examination (dissection)

Not used very often

Air embolism

Occurs when air or gas is admitted into the vascular system

Blood clots, bone marrow, and fat are other types of embolisms

Forensic photography

Many forensic pathologists take their own photographs of both scenes of death and of autopsy appearances

Exhumation

the retrieval of a previously buried body for postmortem examination

Usually followed by a first autopsy or a re-autopsy following new information

When is exhumation required?

Where all or part of a graveyard has to be moved for some development of the ground

Where some civil legal matter needs to be investigated

Where new information or substantiated allegations arise to suggest that a death was due to criminal action

In ancient or historical circumstances to investigate either the individual or a series of individuals for academic interest

Autopsy on the putrefied corpse

Putrefaction (decomposition) hides bruising to a variable degree

Abrasions, lacerations, incised wounds and gunshot wounds may survive severe degrees of decomposition

Resuscitation at autopsy

Bruising of the anterior chest wall, hemorrhage into the subcutaneous tissues and pectoral muscles, fracture of the sternum and ribs, hemothorax, bruised lung or lacerated lung, pericardial hemorrhage, and fractured dorsal spine may indicate CPR

Petechiae in the eyes and intra-ocular hemorrhages can occur after CPR

Other signs of resuscitation

Bruising of the face and neck, finger marks and nail marks on the face and neck

Damage to the lips and inner gums from mouth-to-mouth resuscitation

Damage to lips, gums, teeth and pharynx can occur from the intubation