Wounds & Injuries CNS 2024 PDF

Tu e s d ay, 2 6 th No vem ber 2024 Wounds & Injuries and CNS POTS Dr Yvonne McCartney Year 2 26th November 2024 Pathology Wounds & Injuries RCSI 2024 Dr Yvonne McCartney State Pathologist  1. Describe the different types of injuries / tissue damage and why the...

Tu e s d ay, 2 6 th No vem ber 2024 Wounds & Injuries and CNS POTS Dr Yvonne McCartney Year 2 26th November 2024 Pathology Wounds & Injuries RCSI 2024 Dr Yvonne McCartney State Pathologist  1. Describe the different types of injuries / tissue damage and why they should be distinguished. 2. Describe the factors to be assessed regarding the type of Learning weapon involved in sharp force trauma. Outcomes 3. Describe the main features of gunshot wound injuries. 4. Describe vehicular impact injuries and the factors that can influence these injuries. Graphic Images GRAPHIC IMAGES  DEFINITION Wounds & Injuries Disruption of the normal structure of tissues caused by the application of force  Importance of Accurate Documentation Forensic vs non-forensic autopsy Weapon / implement used E.g. Blunt or sharp object Pattern of the injuries can help determine: Circumstances of injury Accident / suicide / homicide Accuracy in medicolegal reporting  Describing Injuries Wound type Bruise, abrasion or laceration etc. Wound dimensions Length, width, depth etc. Photograph with a scale (e.g. tape measure) Stab wounds Measurements to be taken of the wound as it appears first Then with wound edges drawn together  Describing Injuries Position of the wound in relation to fixed anatomical landmarks e.g. midline, clavicle, ear lobe The height of the wound from the heel (ground level) Pedestrian RTAs 1.53 m Stab wounds  1. Blunt force trauma Types of Injuries 2. Sharp force trauma 3. Mixed injuries Knights Forensic Pathology, 4th edition Blunt Force Trauma Bruises Abrasions Lacerations Sharp Force Injuries Stab wounds Incised wounds Blunt Force Trauma Bruises  Bruises Blunt trauma / injury to the body surface without damage to the epidermis Blood leaks out (extravasation) into surrounding tissues from damaged capillaries, venules and arterioles →Surface bruises (intradermal) →Subcutaneous →Visceral (contusions)  Bruises Bruises may 'appear' after some days Blood tracking along tissue planes 'Shifting' of bruises after time – gravity From face or scalp to neck in head injury patients Extent of bruising is dependent on: Location of injury: e.g. eyes, palms Individual traits: thinness of skin, coagulation  Localisation Number Medical Distribution Evaluation of Bruises Size, shape Pattern – grip/ finger marks Colour Tramline Bruise Two parallel linear bruises separated by a paler, undamaged section of skin When the skin is struck with a rod-shaped object → Blood squeezed from vessels at point of impact → They are empty so don’t leak blood → Edges of the wound stretched, and blood vessels torn, causing blood to leak into the surrounding tissue Tramline Bruise Knights Forensic Pathology, 4th edition Abrasions  Abrasions – Grazes/Scratches Known as a ‘scratch’ or ‘graze’ Either direct impact (crush) or glancing impact across the skin surface resulting in a loss of the epidermal layer only Usually after an object has struck the skin (e.g. a kick), or an injured person has fallen onto a rough surface, such as road Broader surface = 'graze' or 'brush abrasion’ E.g. motorcyclist thrown from vehicle and skids along the road surface Often covers a relatively large area of skin, and is called a 'friction burn’  Forensic Significance of Abrasions Abrasions can retain much of the surface characteristics of the object that caused the wound E.g. car bumper grill Direction of force can often be determined, from the torn epidermis Strands drawn towards the end of injury, and are 'heaped up’ Edges of wound may be ragged and directed towards the end of the wound Dirt, gravel, debris and fibres may be attached or ingrained Knights Forensic Pathology, 4th edition Lacerations  Lacerations Knights Forensic Pathology, 4th edition Known as gashes, cuts or tears Blunt force trauma causing a split / tear in the skin and underlying tissue BLEED PROFUSELY Usually where there is bony support Forehead, scalp and face, knees etc Less common in softer body areas (buttocks) Motor vehicles contact - shearing of the skin from underlying support = Degloving injury  Ragged edges Crushing and bruising of the margins Characteristics of Lacerations Hairs driven into the tissues Tissue strands crossing depth of wound (nerves, fibrous brands, vessels)  Lacerations Knights Forensic Pathology, 4th edition Note: Scalp lacerations may resemble incised wounds when caused by a regular shaped object Sharp Force Trauma Sharp Force Injuries Stab wounds Incised wounds Stab Wounds Stab Wounds Knights Forensic Pathology, 4th edition Stab Wounds Depth of injury >> length. Penetrate more deeply than slash / incised wounds - contact with vital organs in the chest and abdomen Caused most obviously by knives Also bayonets, swords, scissors and blunter instruments such as screwdrivers Stab Wounds External surface / skin injuries are usually slit-like When object is removed - skin contracts Wound slightly shorter than the blade width The centre of wound – widens / gapes The size and shape also depend on: Configuration and movement of the object Direction of thrust Movement of the individuals Knights Forensic Pathology, 4th edition  Clean cut edges One or both ends pointed Non-pointed end may be squared off or split Fish tail or boat-shaped defect Often gape (related to skin elasticity and Langer’s lines) Characteristics Cross section of weapon may be illustrated when edges of wounds opposed of Stab Wounds Underlying bone may be scored by blade Abrasions may be present Frequently shows notching or a change in direction (caused by relative movement of the knife and body) Incised Wounds  Incised Wounds Due to sharp instruments Length > depth Wound margins uninjured Deep tissues cleanly cut e.g. surgeon’s incised wound Also known as Slash wounds  If the wound involves major blood vessels, it can be life threatening, but in general, they Incised Wounds are not as serious as stab wounds  Other Injuries 1. Weals (reddening, swelling, normal tissue response) 2. Glass injuries (cutting or tearing) 3. Axe or Chop injuries (combined blunt and sharp force) 4. Thermal injuries 5. Firearm injuries 6. Defence injuries (forearms, hands, thighs)  7. Fabricated Wounds or Fictitious Wounds Caused by person him or herself, or by someone else with consent Other Injuries Reasons: False accusation of assault or rape To mimic defence injury To aggravate a simple injury  8. Tentative Self-Inflicted Injuries Suicide attempts Short, shallow wounds, usually on wrists or neck Often multiple, superficial and parallel wounds, surrounding a major/deeper wound Usually sharp injuries Other Injuries 9. Self-Inflicted Injuries Deliberate direct damage to body without conscious intent to commit suicide Females > males Mental Disorders - haphazardly inflicted on arms or body In general injuries are: Multiple, superficial and parallel Accessible site; depends on handedness Clothing not damaged Age of Injuries Age of Injuries Colour changes in bruises - purple to yellow Scab formation in abrasions Scabbing and scarring of laceration Histological examination of tissues Immunohistochemistry Age of Bruises Bruises change colour - degradation of haemoglobin Timescale not fixed - rough estimation Colour change - dark blue or purple to blue, brown, green and yellow In a fit & healthy person spectrum could take from 72 hours to 1 week Age of Bruises The more extensive / deep seated the bruise the longer it will take to disappear Yellow bruise – likely to be least 18 hours old Markedly different coloured bruises suggest that they have been caused at different times, and may indicate signs of chronic abuse, such as of an infant etc.  Death from Injuries Haemorrhage Externally into environment Damage to vital Shock Infection Internally: chest, abdomen, structure retroperitoneum, muscle Pulmonary Acute tubular necrosis Fat embolism thromboembolism Fat Embolism Syndrome Pelvic and long bone fractures 12 to 72 hours after major Extensive soft tissue trauma traumatic injury Burns Intravascular embolisation of fat in systemic and pulmonary vasculature from bone marrow or adipose tissue Enter circulation via ruptured vascular sinusoids or venules (7 - 10 um diameter)  Clinical diagnosis of exclusion Respiratory, neurological, cutaneous & haematologic manifestations Petechial rash, anaemia and thrombocytopenia Fat Embolism FES incidence 1 - 3.5% (10% mortality) Syndrome Autopsy: FE in lung, brain, retina and kidney > 90% have recent traumatic injury  Oil Red O stain - fat globules (red- orange) within the pulmonary arterioles The capillary loops of this glomerulus Petechial hemorrhages in white contain fat globules in a patient matter. Cerebral oedema and with fat embolism syndrome. herniation may follow. GUNSHOT INJURIES  Gunshot Injuries Science TYPE OF WEAPON DISTANCE DIRECTION Types Of Weapon Rifled Smooth Bore  Shotguns Single or double barrelled Repeating, semi-automatic Average barrel length = 18 to 36 inches Sawn off < 25 cm / 10 inches Knights Forensic Pathology, 4th edition Knights Forensic Pathology, 4th edition Knights Forensic Pathology, 4th edition  CONTACT Hole about diameter of barrel Shotgun Stellate laceration at bony sites e.g. skull Injuries Contact barrel(s) imprint around wound Scorching of wound margins Pink colour of skin around wound due to CO Soot, powder, shot and wad in wound Shotgun Injuries Knights Forensic Pathology, 4th edition  Shotgun Injuries As the distance between the shotgun and skin increases, the following occur: Loss of contact abrasion mark The appearance and then disappearance of soot around the margin of the wound The emergence and disappearance of powder tattoo around the wound The entrance wound becomes larger and scalloped at first, but then disappears Appearance of pellet wounds and wad Shotgun Injuries Knights Forensic Pathology, 4th edition  Rifling - parallel grooves and lands on inside of barrel (4 to 7) Left or right twist Rifled Weapons Gyroscopic steadiness Leaves marks on surface of bullet The appearances of the most common handgun and rifle rounds are shown here In general, it is difficult to tell from the wound exactly what round was used  Rifle Weapon Injuries Features of rifled entry wound: Neat entry hole Less than diameter of the bullet Soiling of edges by bullet grease Collar of abrasion Edges inverted +/- Secondary projectiles Depending on – range, clothing  Contact Typical entry wound Rifle Blackened, seared margin Imprint barrel muzzle abrasion Weapon All projectiles in wound (bullet + secondary) Injuries Contact to head Stellate shaped entry wound due to gases spreading under skin lifting it from the skull Possible back spatter into weapon  Distance At distance the entry wound will have: Neat hole with a rim of abrasion Rifle Weapon No soot, powder tattoo or pink Injuries discolouration The entry may look irregular if intermediate target or projectile loses spin  Shotgun Only at close range e.g. head Shotgun pellets stopped by bone Rifled Exit less likely if head wound May be irregular with Exit Wounds everted edges Usually larger than entry No bullet grease Multiple exits if projectile fragments or bone fragments expelled through skin  Tissue damage due to energy from projectile Energy depends on size and velocity of projectile Internal Injuries Shotgun pellets slowed by tissues & stopped by bone Bullets from low velocity weapons stopped by bone  Internal Injuries In high velocity projectile: Crushing and laceration of tissues in path of missile Shock waves damage solid tissues and vessels Temporary cavitation, stretches tissues, fractures bones, disrupts vessels and creates vacuum  Haemorrhage Damage to vital structure Shock Death from Infection Injuries Pulmonary thromboembolism Acute tubular necrosis Fat embolism Road Traffic Collisions  1. Describe the causes of motor vehicle collisions 2. Describe the types of injuries sustained to the driver of the vehicle 3. Describe the types of injuries sustained to other occupants of the vehicle Learning 4. Describe injuries sustained from seatbelts and airbags Outcomes 5. Describe pedestrian injuries 6. Understand the importance of the post mortem examination and collection of trace evidence in road traffic collisions 7. Describe the types of injuries sustained in motorcycle accidents  Causes of Motor Vehicle Collisions Natural Vehicle Intoxication Human failings Environmental disease disrepair Alcohol Speed Sudden death Rain, ice, fog Defective tires, Drugs of abuse Reckless driving while driving breaks, steering Prescription Falling asleep drugs Distracted  Drink Driving Legal limits for blood alcohol concentration (Ireland): Experienced drivers: 50 mg / 100 ml Novice / professional drivers: 20 mg / 100 ml Legal limits for blood alcohol concentration (UK): 80 mg / 100 ml Alcohol is a factor in over 1/3 of fatal road traffic collisions in Ireland Drug Driving Legal limits for blood concentration of illegal drugs (Ireland): Cannabis (THC): 1 ng/ml Cannabis (THC-COOH): 5 ng/ml Cocaine: 10 ng/ml Benzoylecgonine (Cocaine): 50 ng/ml 6-Acetylmorphine (Heroin): 5 ng/ml  The Dynamics of Vehicular Injury Acceleration / deceleration: Tissue injury is caused by a change in the rate of movement Change of force: The amount of G-force that a human body can tolerate depends on duration and direction in which the force acts Damage depends on force per unit area Direction of impact: 60 – 80% of vehicular crashes are frontal (deceleration) 6% are rear impact (acceleration) Sideswipes crashtest.org Roll-over  Depends on: Position of Pattern of Type of vehicle occupant in the vehicle Injury to Vehicle Occupants Seat belts & Speed airbags The Driver  Driver Injuries Front Impact, Unrestrained Driver: Legs strike fascia of car Abdomen or lower chest contacts the lower edge of the steering wheel Head moves forward with flexion of cervical and thoracic spines Head strikes windscreen / upper windscreen rim / side pillar Windscreen may break from impact with head Whole body may be ejected from vehicle Knights Forensic Pathology, 4th edition  Driver Injuries Head & Neck: Glass injuries – eye damage Skull fracture Scalp laceration Hyperflexion of cervical spine – fracture / dislocation Trunk: Bruising Rib and sternum fractures from impact with steering wheel Lower Limbs: Abrasions and lacerations Fractures of legs, feet, hip, pelvis Upper Limbs: Abrasions and lacerations Fractures from gripping steering wheel  Driver – Internal Injuries C-spine fractures Intracranial haemorrhage Atlanto-occipital dislocation Diffuse axonal injury Ruptured aorta Heart contusions / lacerations Complete avulsion of the heart Lung contusions / lacerations Liver lacerations / haematoma Contusion of mesentery and omentum Ruptured liver Splenic lacerations Ruptured spleen Other Occupants of the Vehicle Injuries to Other Occupants of Vehicle Front Seat Passenger Rear Seat Passenger No steering wheel injuries Projected forwards into back of the Increased head injuries front seats Projected over front seats and through windscreen Roll-Over Accidents All occupants have multiple injuries Increased risk of ejection from car The Effect of Seatbelts  Seatbelt Laws in Ireland Driver has the responsibility to ensure all passengers under 17 years are suitably restrained All adults must wear a seat belt Exemptions: medical certificate, driving instructor / examiner, An Garda Síochána / Defence Forces 3 – 12 years (> 36 kg) must have appropriate seating 0 – 3 years (< 36 kg) must use child restraint system (suitable for height & weight) Seatbelt Laws in Ireland Seatbelt Laws in Ireland  Seatbelts The use of seatbelts reduces the risk of fatal injury by 40 – 50% for drivers & front-seat occupants and by 25 – 75% for rear-seat occupants. Increased unit are over which force is applied Extend deceleration time Prevent ejection Prevent head injuries Knights Forensic Pathology, 4th edition  Seatbelt Injuries Bruising Abdomen, chest wall Internal Injuries Rib and sternal fractures Spinal fractures * Rupture of small intestine / large intestine / mesentery * Rupture of bladder (esp. If full) Rupture of aorta * * increased risk with single lap strap Airbags  Airbags Front and side airbags in most modern domestic cars Contains sodium azide (solid and highly toxic explosive propellent) Can reach speeds of over 300 km / hr seat.ie Deflation is rapid to allow escape from the car Inflated bag is designed to: Interpose itself between occupant and structures of the car Cushion the impact Prevent forceful contact and hyperflexion irishmirror.ie  Chemical burns Facial bruising Eye injuries Arm and hand fractures Airbags - Spinal fractures Injuries Head injuries Illegal to use a rearward-facing child car seat in a passenger seat with an active airbag Can cause serious injury and death to the child Pedestrians  Pedestrian Injuries Most common road traffic collision fatalities Injuries: Primary - contact with vehicle Secondary - further contact with vehicle Tertiary - contact with the ground Knights Forensic Pathology, 4th edition  Injury pattern depends on: Speed of the vehicle Pedestrian Braking Injuries Type of vehicle Size / age of victim (adult / child)  Pedestrian Injuries Speed of Vehicle High speed Picked up and knocked forward or over the car Increased severity of injuries Lower speeds Onto bonnet and then off to the side of the car Braking Lowers bumper height Knights Forensic Pathology, 4th edition  Pedestrian Injuries Type of Vehicle & Bumper Height Impact above centre of gravity Knocked down +/- run over by the car Impact below centre of gravity Picked up and either thrown forwards or onto bonnet Children Tend to be knocked forwards as the impact is higher up on their body Projected further by the impact Increased risk of being run over by the vehicle  Pedestrian Injuries Patterned injuries Bumper, headlights Tyres Bumper fractures Lower leg (tibia / fibula) – closed / compound Standing – both legs fractured at same height Walking / running – fractures at different levels Side impact – single leg fractures (ipsilateral)  Injuries to Upright Pedestrians Legs Most common trauma is to the legs (85% of pedestrian casualties have lower limb injuries) Abrasions & lacerations to upper shin / knees Tibia / fibula fractures Head injuries Second most frequently injured region Most common cause of death Impact with windscreen, pillars, roof, ground Scalp lacerations Skull fractures Chest, abdominal, pelvic and limb injuries Usually concentrated on one side (opposite side to point of primary impact) Often widespread with no particular pattern Pedestrian Injuries – Trace Evidence Documented and photographed in situ Retained (NB – chain of evidence) On Victim Paint, glass, car parts Marks on clothing (tyres) On Vehicle: Blood, tissue, clothing fragments The Body Found on the Road The Body Found on the Road Hit-and-run? Number of times run-over? Number of cars involved? Post Mortem Examination: Identification of the body Identifying patterned injuries Collection of trace evidence Natural disease Toxicology  The Body Found on the Road Run Over Injuries Body crushed between road and vehicle Degloving / flaying injuries to skin and muscle Flail chest (bilateral rib fractures) Spinal fracture Heart and lungs crushed or lacerated Bilateral pelvic fractures Injuries to lover, spleen, intestines, mesentery Motorcycle Deaths  Motorcycle Deaths Higher rate of injury and death amongst motorcyclists compared with car drivers 34-fold increased risk of death per vehicle mile travelled Head & neck injuries: Common and often severe Skull fractures (basal skull facture – hinge fracture; ring fractures) Cervical spine fractures Cortical contusion and laceration Limb injuries: Lacerations, friction burns, factures (often compound) Trunk injuries: Rib fractures, spinal fractures Visceral damage motogp.com  Motorcycle Deaths Brush abrasions: From friction / skidding along the road Can cover large areas of the body surface Traumatic asphyxia or crush injury: Heavy bike falls on top of the victim Tailgating accident: Motorcyclist drives into the back of a truck, bikes goes under the truck and motorcyclists head impacts the tailboard of the truck Severe head and neck injuries Decapitation Passengers of motorcycle: Fall backwards Posterior scalp lacerations, skull factures and brain contusions  Things to Remember All road traffic collisions in Ireland are routine Coroner’s PMs Hit and run cases are forensic “State” cases Document and measure patterned injuries and bumper injuries from anatomical landmarks The overall pattern of injury is helpful in establishing what happened In conjunction with forensic crash investigation Summary  Wounds & Injuries Importance of accurate documentation of wounds & injuries Importance of recognizing the different types of injuries and to understand how they may have occurred Recognise the difference in sharp force injuries (stab versus incised wound) and blunt force trauma Gunshot Injuries Summary Recognise the different characteristics of entry versus exit wounds Understand the characteristics of close / distance range injuries Road Traffic Accidents Understand the types of injuries that may occur to the driver and other occupants of the vehicle Understand the types of injuries that may occur to pedestrians and to motorcyclists  Questions? 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