Asphyxia Lecture Notes

A set of vocabulary flashcards for reviewing key concepts related to asphyxia.

Asphyxia

Interference with the uptake or utilization of oxygen.

Oxygen Utilization in the Brain

The brain utilizes 20% of the total available oxygen.

What is the most sensitive organ to oxygen deprivation?

The brain is the most sensitive organ to oxygen deprivation.

Compression of the Neck

Includes hanging and strangulation.

Obstruction of the Airway

Can occur from smothering, aspiration of foreign material, or swelling of the throat.

Postural Asphyxiation

Asphyxia due to the position of the body.

Compression of the Chest

Interferes with respiratory movement.

Exclusion of Oxygen

Due to depletion or replacement by another gas or chemical interference with oxygen uptake.

Examples of Chemical Interference

Carbon dioxide, carbon monoxide, cyanide poisoning.

Hanging

Death usually results from lack of arterial blood flow to the brain or obstruction of venous return. Can be performed in various body positions.

Petechiae

Ruptured capillaries due to increased venous pressure, commonly found in the conjunctivae, forehead, and eyelids.

Petechial Hemorrhages

Found in over 50% of suicidal hangings.

Knot Behind the Ears

Interferes with blood flow both to and from the brain.

Knot Under the Chin

Interferes with venous outflow.

Loss of Consciousness

Occurs when the brain is deprived of oxygen.

Pressure Required to Occlude Carotid Arteries

4-6 lbs. of pressure is required.

Pressure Required to Block Airway

32 lbs. of pressure is required.

Effects of Body Weight

Increased pressure from body weight can cut off all blood flow.

Compression of the Airway in Hanging

Uncommon occurrence

Cervical Vertebra Fractures

Rarely seen in hanging cases.

Hanging Evidence

Ligatures usually leave distinctive, recognizable evidence. Hanging can be easily accomplished; various nooses can suffice.

• Examples include belts, dog chains, etc.

Ligature Clue

Groove or furrow in soft tissue can indicate the type of ligature used.

Noose Effects

Multiple wrappings of the noose around the neck can pinch skin, altering appearance.

Friction from Tight Noose

Can cause serum-filled blisters.

Protrusion of Tongue

May occur due to upwards pressure from ligature.

Manual Strangulation

Considered a homicide with potential evidence such as fingertip bruises and marks. Also must preserve the knot always.

Neck Organs Assessment

Removal and assessment are required during autopsy.

Fractures of the Larynx

Includes hyoid bone, thyroid cartilage, and cricoid cartilage.

Smothering Causes

Blockage of the nose and mouth due to pillows, plastic bags, or bedding.

Aspiration Causes

Can be due to intoxication, food, or vomitus.

Swelling of the Lining of the Larynx

Can occur due to insect bites or anaphylactic shock and epiglottitis and diphtheria

Positional/Compression Asphyxiation

Occurs when the position of a person physically obstructs their ability to breathe. Other objects may also prevent breathing.

Manual self-strangulation

It is is generally infeasible.