THERMAL INJURIES

Thermal injuries, commonly known as burns, occur when the skin or other tissues are damaged by heat.  When excessive heat is transferred to the skin, it radiates outward from the point of contact and initiates local and, if severe enough, systemic responses from the body.  The mechanism of injury depends on the heat source which can include flames, hot liquids, hot solid objects, and steam. The severity of the burn depends on the heat source temperature and duration of contact.

There are various types of thermal injuries:

• Flash and flame burns: These can occur when someone is directly or indirectly exposed to a flame.

• Scald burns: These occur when someone is exposed to a high-temperature liquid or steam.  The exposure is generally from either a spill or immersion such as into a hot bathtub.

• Grease burns: These occur when someone is exposed to high-temperature grease. Since grease has a higher viscosity than water and other thinner substances, it travels down the skin more slowly.  Grease also does not evaporate resulting in a longer contact time with the skin.  Therefore, these burns can be deeper than they initially appear.

• Contact burns: These occur when someone comes into direct contact with a high-temperature object such as burners on a stove.

• Inhalation injuries: Open flames in an enclosed space can cause facial and supraglottic burns.  The products of combustion travel into the respiratory tract and cause mucosal irritation, bronchospasm, local or systemic inflammation, and capillary leak. This type of injury can be seen in house fires.

Resulting Injuries related to thermal injuries

• Depth of Injury: The depth of thermal injury is directly related to the contact temperature, duration of exposure, and the thickness of the skin. Burns are typically classified into three degrees:

• Local Response: The body’s response to a burn includes three zones similar to the rings of a bullseye.

1. Zone of Coagulation: This is the center of the bullseye and is the area of maximum damage where tissue is irreversibly destroyed.

2. Zone of Stasis: This is the next ring of the bullseye as you move out and surround the zone of coagulation.  This area has decreased tissue perfusion but is potentially salvageable with proper treatment.

3. Zone of Hyperemia: The outermost ring of the bullseye and the one furthest from the point of contact. This area has more blood flow than the others and can usually recover unless there is a severe infection or prolonged hypoperfusion.

• Systemic Response: Severe burns can trigger a systemic response, especially if they cover a large body surface area. This response can include:

  • Cardiovascular Changes: Increased capillary permeability leads to fluid loss and systemic hypotension.

  • Respiratory Changes: Inflammatory mediators can cause bronchoconstriction and, in severe cases, adult respiratory distress syndrome (ARDS).

  • Metabolic Changes: The basal metabolic rate can increase significantly, necessitating early and aggressive nutritional support.

Other Factors: Burns can also result from electrical discharge, friction, chemicals, and radiation. Each of these causes has its own unique mechanism of injury and effects on the body.

ACCELERATION/DECELERATION TRAUMA

Forensically, acceleration/deceleration injuries are often referred to as whiplash injuries.  They frequently occur as a result of high-speed vehicle accidents, abusive head trauma/physical abuse, or falls.  These injuries result from rapid changes in velocity involving the forward and backward movement of the head and neck and can lead to potential damage to the soft tissues, ligaments, and muscles in the cervical region as well as severe head injuries.

Here’s a breakdown of the mechanism:

1. Sudden Change in Velocity: When the body experiences a sudden stop or start, different parts of the body may move at different speeds. For example, in a car crash, the torso might be restrained by a seatbelt and stop with the vehicle, but the head continues to move forward at the speed the vehicle was moving, leading to injury.

2. Shearing Forces: The differential movement between the fixed and mobile parts of the body creates shearing forces. These forces can cause significant damage to tissues, particularly in the brain, where the brain tissue moves at a different rate than the skull.

Resulting Injuries:

1. Diffuse Axonal Injury (DAI): A type of traumatic brain injury (TBI) and one of the most severe outcomes of shearing forces.  The axons (nerve fibers) in the brain are stretched and torn as the brain moves rapidly within the skull. This can lead to widespread brain damage and is a common result of high-speed impacts from coup-contrecoup forces.

2. Whiplash: A specific type of acceleration/deceleration injury, often seen in rear-end car collisions, is whiplash or cervical hyperextension injuries. This involves a rapid back-and-forth movement of the neck, leading to soft tissue damage.

3. Internal Organ Damage: The rapid deceleration can also cause internal organs to collide with the body’s skeletal structure, leading to bruising, bleeding, or even rupture.

Signs and Symptoms of acceleration/deceleration injuries can vary depending on the organs affected, but some common signs include:

Signs and Symptoms of DAI:

1. Loss of consciousness

2. Headache

3. Dizziness

4. Nausea and/or vomiting

5. Difficulty with balance and/or coordination

6. Confusion

7. Cognitive impairments, such as memory loss or difficulty concentrating

Signs and symptoms of whiplash and internal organ injury:

1. Abdominal Pain: Persistent or severe pain in the abdomen can indicate damage to organs like the liver, spleen, intestines, or internal hemorrhage.

2. Nausea and Vomiting: These symptoms can be a sign of internal bleeding, traumatic brain injury (TBI), or organ damage.

3. Difficulty Breathing: This can occur if the lungs or diaphragm are injured.

4. Dizziness or Lightheadedness: These symptoms can result from internal bleeding leading to a drop in blood pressure or from whiplash injuries to the neck.

5. Weakness or Feeling Faint: Similar to dizziness, this can be due to significant blood loss.

6. Cervicogenic Headaches: Headaches that generate from the neck and radiate to the temple, top or front of the head, or down the neck

7. Numbness: In the arms and/or hands.

8. Neck pain: Pain that worsens when moving the neck, or stiffness and difficulty moving the neck

9. Headaches: Headaches that often start at the base of the skull

10. Pain: In the shoulders, upper back, arms, or jaw

11. Blurred vision

12. Tiredness, irritability

BALLISTIC TRAUMA

Ballistic trauma is a type of traumatic injury caused by firearm-related wounds or other projectiles. The damage to tissues depends on the kinetic energy of the projectile, which influences the amount of energy that the object has available to transfer to tissue. Ballistic trauma varies widely based on the bullet, velocity, mass, entry point, trajectory, affected anatomy, and exit point; and can have serious long-term health and economic consequences.

It is in ballistic trauma that perforating trauma is more likely to be found, as opposed to a stabbing or other penetrating injury.  Locating and identifying the exit wound is important not only for treatment purposes but also for forensic and crime reconstruction purposes.

Additional injury types include penetrating, the bullet enters the body, but does not exit; re-entry, the bullet enters, exits, then re-enters the body; and graze or tangential, a superficial wound caused by a bullet striking the skin at a shallow angle.

Injuries from ballistic trauma are influenced by many factors to include:

• Velocity of the firearm - high-velocity firearms, such as rifles, cause greater and more extensive tissue damage, whereas lower velocity firearms, such as a handgun, cause more localized tissue damage

• Projectile characteristics - type, composition, shape, the tendency to explode, deform, or fragment

• Density of the affected tissues

• Distance of fire

Ballistic trauma involves two primary mechanisms of injury:

1. Permanent Cavity: This is the direct path taken by the bullet as it crushes and destroys tissue. The extent of this damage depends on the bullet’s type, velocity, and mass, as well as the physical characteristics of the tissues it passes through.

2. Temporary Cavity: As the bullet travels through the body, it creates a temporary cavity by stretching and shocking the surrounding tissues. This cavity is larger than the bullet itself and can cause significant damage to organs and tissues outside of the bullet’s path.

Common complications following ballistic trauma depend on the location and severity of the injury. Here are some of the most frequent complications:

1. Infection: Due to the introduction of foreign materials (like bullet fragments or clothing) into the body, infections are a significant risk.

2. Vascular Injury: Damage to blood vessels can lead to severe bleeding, hematomas, or even loss of limb if not promptly treated.

3. Nerve Damage: Bullets can sever or damage nerves leading to loss of function or sensation in affected areas.

4. Fractures: High-velocity bullets can cause complex fractures, which may require extensive surgical intervention.

5. Compartment Syndrome: Increased pressure within muscle compartments can lead to tissue death and require emergency surgery.

6. Chronic Pain: Long-term pain, including conditions like hyperalgesia (increased sensitivity to pain), can persist long after the initial injury.

7. Lead Poisoning: Retained bullet fragments can lead to lead poisoning over time.

8. Organ Damage: Depending on the trajectory, bullets can cause significant damage to internal organs, leading to long-term complications like bowel obstruction or neurogenic bladder.

PENETRATING TRAUMA

Penetrating trauma occurs when an object pierces the skin and enters the body causing damage. These types of traumas are typically the result of injuries from sharp objects (like knives or broken glass) or high-energy projectiles (such as bullets).

Penetrating trauma can also be “perforating trauma”. Perforating trauma occurs when an object enters AND passes through the body creating entrance AND exit wounds. Perforating trauma is most commonly associated with ballistic wounds, which will be covered in another post; this post will focus on penetrating injuries.

The type and severity of resulting injuries depends on several factors, including:

• Location: Wounds to vital areas such as the chest, abdomen, or head can be life-threatening due to potential damage to critical organs or blood vessels.

• Depth: Shallow wounds might only affect the skin and underlying tissues, while deeper wounds can impact muscles, organs, or bones.

• Type of Object: Sharp objects tend to cause cleaner cuts, while blunt or high-energy objects can cause more extensive damage and bleeding.

• Obstacles: If an object has to go through clothing or other objects to reach the skin, the injury may be lesser in depth and severity

• Force: The stabbing force is influenced by the shape of the blade/object and stabbing velocity.  Generally, the greater the stabbing force the greater the depth and potential injury

• Victim: The underlying age and general health of the victim can influence the injury severity and healing

Common types of penetrating injuries include:

1. Knife Wounds: These cause incision (slash marks) or stab (puncture) wounds depending on how the knife is wielded. Damage can range from superficial skin injuries to deep wounds affecting muscles, blood vessels, or organs.  Sharp weapons can also strike bones resulting in a bone fracture, the knife tip could break off in the bone.  There can be a transfer of trace evidence from the knife to the bone or bone fragments onto the knife blade.

2. Puncture Wounds: Caused by sharp objects that penetrate the skin and underlying tissues, creating a small but deep wound.  They can potentially damage deeper structures like muscles, tendons, and organs, and may have a higher risk of infection.

3. Lacerations: These are tear-like wounds caused by sharp objects. Unlike clean incisions, lacerations may have irregular edges and can damage both the skin and underlying tissues. They can be superficial or deep, depending on the force and nature of the object.

4. Stab Wounds: These are a specific type of penetrating injury caused by sharp, pointed objects like knives. Stab wounds can cause severe damage depending on the depth and angle of penetration, potentially affecting internal organs, blood vessels, and other vital structures.

5. Gunshot Wounds: Often referred to as GSWs, these can cause significant damage due to the high energy of the bullet. The injury typically includes a combination of a wound channel where the bullet penetrates, as well as potential tissue damage from the bullet’s impact and fragmentation. Bullet wounds can affect bones, organs, and major blood vessels, leading to severe bleeding and trauma. Bullets or other projectiles cause these injuries. They can lead to a combination of entry and exit wounds, along with tissue damage from the bullet’s path and potential fragmentation

6. Fractures: Penetrating trauma can also result in broken bones, especially if the object causing the injury is large or if it impacts the bone directly.

7. Organs and Vessel Damage: Depending on the location and depth of the penetration, internal organs (such as the lungs, liver, spleen, or intestines) and major blood vessels can be damaged, leading to potentially life-threatening internal bleeding and organ dysfunction.

8. Infection: When the skin is broken, pathogens can be introduced into the body. These wounds can become infected if not properly treated and cleaned, leading to complications like abscesses or systemic infections.

BLUNT FORCE TRAUMA

Blunt force trauma, also known as non-penetrating trauma, occurs when the body is struck by or strikes a blunt object, leading to injury.  Although the weapon or object does not actually penetrate the skin, the skin may be broken due to the type and force of the impact. The mechanism of action involves several forces:

1. Acceleration and Deceleration: Rapid changes in speed that cause internal organs to move at different rates leading to tearing or shearing injuries.speed changes

2. Shearing: The slipping and stretching of organs and tissues in relation to each other causing significant internal damage.

3. Compression:  The body is squeezed between two objects leading to crushing injuries.

4. Torsion: Twisting forces that cause injuries to muscles, ligaments, and other soft tissues.

5. Crushing Pressure: Prolonged pressure on the body resulting in severe damage to muscles, nerves, and blood vessels.

These forces can result in a variety of injuries, including bruises, fractures, and internal bleeding. The severity of the injury often depends on several factors, such as the underlying age and health of the victim, presence of medications or other substances, and the force and location of the impact.  Some common types of injuries include:

1. Contusions (Bruises): The rupture of small blood vessels under the skin causing discoloration and swelling.

2. Abrasions: Superficial injuries where the top layer of skin is scraped off.

3. Lacerations: Deeper cuts or tears in the skin and underlying tissues.

4. Fractures: Breaks or cracks in bone due to the direct impact, shearing, compression, torsion or compression forces.

5. Internal Injuries/Bleeding: These can include damage to internal organs, such as the liver, spleen, or kidneys.

6. Traumatic Brain Injuries (TBI): These occur when the head is struck, leading to concussions or more severe brain damage.  Shockwaves from explosions can also cause TBIs.

Common signs of blunt force trauma can vary depending on the type, severity, extent, and location of the injury. Here are some typical symptoms:

1. Pain or Tenderness: This is often the first sign, occurring at the site of impact.

2. Bruising: These are common as blood vessels are damaged under the skin.  The bruising results from the leaking of blood from the damaged vessels (venules and capillaries).

3. Swelling: This occurs as a result of the increased blood/increased fluid movement to the area and the influx of white blood cells to the injured area (the body’s initial healing response injury)

4. Difficulty Breathing: This can occur if the trauma affects the chest or abdomen.

5. Nausea and/or Vomiting: These symptoms can indicate internal injuries.

6. Dizziness and/or Loss of Consciousness: This is particularly concerning and may suggest a head injury.

7. Internal Bleeding: This can be life-threatening and may not be immediately visible.

Blunt force trauma can cause death in a variety of ways which include:

• Intracranial bleeding and/or Cerebral Edema (swelling)

• Severe blood loss/Hemorrhage

• Pneumothorax (air accumulating in the space between the lung and chest wall)

• Hemothorax (blood accumulating in the space between the lung and chest wall)

• Aspiration of blood/stomach contents into the lungs

• Deep Vein Thrombosis (blood clot that forms in a deep vein)

• Pulmonary Embolism (part of a DVT that breaks off and travels to the lungs)

WHAT DO FORENSIC NURSE CONSULTANTS MEAN BY "MECHANISM OF INJURY"?

Mechanism of injury (MOI) refers to the method by which damage or trauma occurs to the body (skin, muscles, organs, and bones).  Now, this is where forensic nurses get to use those high school and freshman college physics lessons!  Understanding MOIs and the resulting bodily insults requires combining a bit of physics with anatomy and physiology to determine the effect of the manner (type), direction, amount, and location of force applied to the body and the resulting injury/injuries.

Isaac Newton’s First Law of Motion states that a moving object will continue to move at the same speed until an opposing or outside force acts upon it.  When this happens, the object’s kinetic energy is transferred to the outside object. For our purposes, the object is a weapon of some type, and the outside object is the body and this transfer of energy causes trauma or injury (typically, blunt/non-penetrating or penetrating). However, the transfer of energy can also be through a thermal agent such as heat, chemical, or cold agents and can also cause trauma to the body. This concept of the transfer of energy helps healthcare providers assess the likelihood and severity of injuries based on the nature of the incident and the Forensic Nurse Consultant to link (or not) the injuries to the indicted charges.

In forensics, determining the mechanism of injury (MOI) is crucial for understanding how an injury occurred, which can help in criminal investigations and legal proceedings. Forensic experts analyze the physical forces and mechanical processes that caused the injury to determine the nature of the incident (i.e. accidental, self-inflicted, self-defense, or an intentional violent act).  For example, in cases of blunt force trauma, the MOI can help differentiate between injuries caused by falls, car accidents, or assaults. Similarly, in cases involving sharp force injuries, understanding the MOI can reveal whether the wounds were caused by knives, glass, or other sharp objects and the directionality and/or angle of entry.

More specifically, when evaluating a case, Forensic Nurse Consultants consider the following:

1. The nature of force applied to the body

2. The estimated amount of force applied to the body

3. The events leading up to the transfer of energy/trauma

4. Positioning, location, and movement of the assailant and victim

5. Physical capabilities of the assailant

6. General medical condition of the victim

7. Post-injury medical care (when and what) provided to the victim

MOI can be crucial in determining court cases for several reasons:

1. Establishing Liability

2. Supporting Evidence

3. Refuting or Confirming Defenses

4. Accurate Diagnosis and Treatment

MOIs are broadly sorted into several categories, based on the type and amount of energy transferred. Each has distinct characteristics and associated injuries.

1. Blunt

2. Penetrating

3. Ballistic

4. Acceleration/Deceleration

5. Thermal

6. Chemical

7. Electrical

8. Blast

9. Crush

10. Asphyxial

HOW FORENSIC NURSE CONSULTANTS EVALUATE VIDEO FOOTAGE IN CRIMINAL CASES!

Forensic nurses play a crucial role in assisting law enforcement with evidence collection and attorneys with analysis of this evidence. Part of this in-depth review includes reviewing video footage.  They will often be provided with video footage such as:
🎥 Body-Worn Camera Footage
🎥 Surveillance Cameras
🎥 Dash Camera
🎥 Security Systems
🎥 Interview Room Cameras
🎥 Personal video from victim, witness, or perpetrator

When forensic nurses review video footage, they focus on several key aspects:
👀 Injuries and Trauma:
They look for signs of physical injuries, such as cuts, bruises, or gunshot wounds. They also watch for the individual's movement, range of motion and for any signs of pain. Assessing the severity and location of injuries helps determine the force used and the potential impact on the victim’s current and future health.

👀 Behavioral Observations:
Forensic nurses pay attention to the behavior of both victims and suspects.
They note any signs of distress, fear, or aggression, which can provide valuable context. If a victim/suspect is known or suspected to be under the influence of drug or alcoholic substances, the forensic nurse can observe their behavior to corroborate or refute these assertions.

👀 Evidence of Assault or Abuse:
They examine the footage for any actions that indicate non-consensual behavior. Detecting signs of sexual assault, domestic violence, or other forms of abuse is crucial.

👀 Timelines and Sequences:
Forensic nurses verify the sequence of events. They correlate actions captured on camera with victim statements and other evidence.
They are also able to determine the injury progression through the videos if multiple videos were taken over a period of time.

👀 Medical Interventions:
If medical interventions occur during the footage (e.g., CPR, wound care), forensic nurses assess their appropriateness and effectiveness.

👀 Crime Scene:
Look at the crime scene to determine if there are elements that may have impacted the injuries sustained or explain the lack or absence of injury.
Reviewing police camera footage enables the forensic nurse consultant to obtain a “real-time” view of the incident aftermath and to obtain information with context that is lost with written/document evidence and photographs.  Helps them provide expert insight.

How can Forensic Nurse Consultants impact criminal charges?

🔎 Mitigating Factors:
Forensic nurse consultants identify mitigating factors related to the injuries. They examine all available documentation to understand the case background and context of the injuries. They also review all medical records of the alleged victim and/or perpetrator for medical conditions or medications that may have contributed to the injuries.

🔎 Severity Assessment:
The severity of the injury needs to meet the definition of the charges.  By accurately determining injury severity, forensic nurses can provide expert input as to whether charges could be upgraded or downgraded.
❓ Are the injuries consistent with the explanation?
❓ Are there alternative explanations?
❓ Do the injuries look chronic or recent?
❓ Are there injury patterns that may indicate the type of object used?
❓ Do the medical records provide clear timeline of the medical history?
❓ Were there treatments, previous injuries, or follow-up appointments?
❓ Are there inconsistencies that could indicate underlying issues?
❗ They consider factors like healing time, pain level, and long-term consequences such as disfigurement, scarring, physical limitations, loss of function, and/or risk of death.
📸 They interpret photographs of injuries taken at different stages (immediately after the incident and during healing) and document the extent and progression of injuries visually. The absence of photographic evidence of injuries significantly hinders injury evaluation and analysis

🔎 Expert Testimony:
Forensic nurses can testify in court as expert witnesses. The objective of their testimony is to educate the judge and jury on the medical evidence and issues in order for an informed decision to be made. Their objective analysis can support a defense argument for reduced charges or the prosecution argument for greater charges.

🔎 Collaboration with Legal Teams:
Forensic nurses work closely with attorneys, providing insights into the medical aspects of the case. They collaborate with legal teams to build a stronger defense or prosecution litigation strategy and/or negotiate plea deals.

⭐ Forensic nurses DO NOT directly change the charges but contribute valuable information to the legal process.