DEFINITION OF WOUNDS Medical definition Disruption of the

DEFINITION OF WOUNDS Medical definition: Disruption of the continuity of the tissues produced by external mechanical force. Legal definition: Breach of the full thickness of the skin

Wounds Medico legal divisions of wounds • 1 - accidental • 2 - sucidal • 3 - homicidal • 4 - self inflecting •

Blunt Force Trauma • There are Four Main Divisions of Blunt Force Type Injuries. • They are: – Abrasions or scrapes: scratches and grazes – Contusions or Bruises (leakage of blood from vessels = extravation) • Extra = outside; vasa = vessel – Lacerations or Tears – Fractures of Bone(s)

Types of wounds Abrasions Lacerations Bruises Incised Wounds

Types of wounds

Blunt Trauma • The severity of blunt trauma depends on: – Amount of force delivered – Time over which the force is delivered – Region struck – Extent of body surface struck – Nature of the Weapon

Blunt Trauma Wounds • The larger the area over which the blow is delivered the less severe the injury • An object that projects from the weapon will deliver all of the force • Rounded portions of the body can sustain greater injuries

ABRASIONS There are three types of Abrasions - Impact - Patterned - Scrapes

Abrasions • It is the most superficial type of injuries that does not penetrate the full thickness of the skin (usually confined to the epidermis). • Usually caused by blunt force trauma.

Characteristics of Abrasions • They are usually not life threatening although they are painful. • They heel without scarring. • Bleeding/Exudation is slight and leads to crust/scab formation. • Might be associated with bruising and laceration

Blunt Trauma Wounds • Abrasions: – An injury in which there is removal of outer layers of tissue by compression or a sliding force – Indicates EXACT site of contact or impact – In living persons the wound will scab over and become dry and darken – Postmortem the wound is yellow with a parchment-like appearance

A linear abrasion or ‘graze’, confined to the upper layers of the skin. The tangential direction of impact of the weapon was from above downwards (along the longitudinal axis of the upper arm), as can be determined by the shreds of epidermis peeled towards the lower end.

What is the Forensic Significance of Abrasions? • Indicates violence • Its shape gives an idea about the causal instrument – Bite abrasions take the pattern of the teeth • Site of abrasion denotes the type of crime • Age of abrasion can be estimated so the time of the incident is known • Helps in identification of the assailant as in bite abrasion

Types of abrasions Direct vertical impact: 1) The force is usually applied vertically onto the skin and causes crushing of the epidermis. 2) The causative object may stamp it’s shape on the skin. Examples: • Fingernail impression and bite mark, and marks of a vehicle radiator on a pedestrian victim or the pattern of a floor grid on to which a person has fallen.

Types of abrasions Tangential impact( brush abrasions) : • Loss or scraping of the epidermis due to friction against a rough surface (graze) or a sharp surface (scratch) • Broader surface

• Example of a brush abrasion of the abdomen by scraping along a rough sooted and rusty surface of a metal tank during a fall. This example of brush abrasions. It illustrates a motorcycle fatality, where the victim has come in contact with the road surface.

Types of Abrasions • Impact Abrasions – The blunt force is perpendicular to the surface of the body • Mostly seen over bony process – Eyebrows – Cheekbone – Nose

Types of Abrasions

Blunt Trauma Wound Patterned Abrasions – This occurs when the object which impacts the body leaves an imprint or stamp on the skin – Be aware postmortem insect bites may resemble patterned abrasions

Patterned Abrasion

Types of abrasions Fingernail abrasions • These are important because of their frequency in assaults especially child abuse, sexual attacks and strangulations • Often associated with focal bruises. – Fingernails abrasions are most often seen on the neck, face, and the upper arms and the forearm

Fingernail Abrasions

Types of abrasions Post mortem abrasions: • Unlike post mortem bruises, artifactual abrasions are common. • They may have been inflicted after death from a variety of causes, including dragging a corpse or buffering in moving water. Some post mortem animal injuries resemble abrasions such as insect bites.

Blunt Trauma Wound • Dating Abrasions is a complicated process – Scab formation begins in 4 -6 hrs and is usually complete in 18 hrs – The skin underneath the scab begins to regenerate within 72 hrs – Once the scab falls off the skin will remodel and become thinner after about 12 days

Importance of abrasions in forensics • Always reflects the site of impact. • Often indicates the causative agent. • Often indicates the direction of impact. • Helps in determining the time of injury.

Mechanical Injuries • Are those, which are caused by the physical violence to the body, depending on the manner and how they are caused. • Examples: - Blunt force injury. Sharp force injury. Fire-arm injury.

Classification of Mechanical Injuries Blunt Force Injuries/Trauma: Abrasions. Contusions, . Lacerations. Sharp Force Injuries/Trauma: Incised wounds. Stab wounds. Chop wounds.

Contusion/Bruise • Contusion is an infiltration or extravasion of blood into the tissue due to rupture of vessels by the application of blunt force. • Examples: -Stick, stone or fist. • Its subcutaneous without discontinuity of skin.

Features of contusion • Varies in sizes-Haematoma. • Superficial contusions are slightly raised over the skin. • May not be present at site of the impact. • Superficial contusions appear soon with red colour. • Deeper contusion appear late, can be detected by infra red photography. • Contusions over bony prominences are less visible externally.

Factors modifying the appearance of contusion • • Site of injury. Vascularity of the part. Age. Sex. Colour of the skin. Nature of disease. Shifting of blood due to gravity.

Colour changes in the contusion • Colour changes in the contusion is due to disintegration and haemolysis of red blood cells. • Haemosiderin-Iron pigments, dark brown colour to blue colour. 2 -4 days. • Haematoidin-Iron free pigment. Green in colour. 57 days. • Bilirubin-Yellow colour. 7 -10 days. • Normal colour of skin 15 -20 days. • Pigments are removed by phagocytes.

Intradermal bruising showing the pattern of rubber soles of ‘trainer’ shoes on the neck and T-shirt of a homicide victim.

Multiple bruises on the trunk of a victim of child abuse. The bruises are of the ‘fingertip’ type, caused by heavy prodding by adult fingers. The child died of a ruptured liver.

Patterned abrasion and intradermal bruising of the face during a fatal armed robbery. The watchman was struck in the face by an assailant wearing a hard-corded driving glove with a coarse weave pattern.

Kicking and stamping injury to the face. The nose is bruised from a kick and the patterned rubber sole of the shoe has imprinted intradermal bruising on the forehead. It is essential to obtain accurate photographs and measurements of the shoe-tread pattern, to allow identification of the footwear.

Extensive bruising of the face due to hitting, kicking and stamping 6 days earlier. The victim had multiple fractures of the facial bones, bilateral serial rib fractures and a tension pneumothorax.

Bruises from a beating with a broom handle. They are approximately parallel and several, especially the lowermost, show a double ‘tram-line’ appearance typical of the impact of a round or square-section rod. The pressure in the centre compresses the vessels so that they do not bleed.

Suction marks in the left breast of a 22 year-old homicide victim, who was killed by manual and ligature strangulation.

A black eye (peri-orbital haematoma) of a live victim from a direct fist blow, which has also bruised the bridge of the nose and lacerated the corner of the eye (sutured).

Laceration wounds/Injuries • These are the wounds caused by the blunt force resulting torn of the skin and the underlying tissue, with a minimal bleeding.

Features of the lacerated wounds • • • Edges are ragged, irregular and contused. Margins are abraded due to impact of blunt force. Deep tissues are crushed. Hair bulbs are crushed. Less bleeding due to crushing of underneath vessels. • Presence of foreign materials. • Shape-Irregular. • Size-May or may not correspond to the weapon.

• • • Margins-Irregular Floor-Tags of tissue seen across the floor. Damage to the tissue-Gross and extensive. Haemorrhage-Less because of crushing of vessels. Foreign substances at the site of injurydust, mud, gravels etc. • Healing-Process delayed due to gross damage and infection. • Scars-Due to damage to skin and tissue.

Laceration of the eyebrow with surrounding bruising. The wound is stellate as a result of crushing against the underlying bone. The victim fell from a low cliff on to rocks. The sea has washed away the original bleeding.

Multiple homicidal lacerations of the scalp. The unusual shape is difficult to interpret, but they were caused by a claw hammer. Two are triangular, the upper and lower show tissue bridges because of the gap between the two claws

Laceration of the scalp from a 30 cm long heavy torch (insert). The skin over the shoulders is reddish due to firstand second-degree burns. The victim was hit on the head while sleeping in bed, after which the husband poured petrol over the body and set it on fire.

Homicidal lacerations of the scalp penetrating the skull. Although some of the injuries resemble incised wounds, their margins are crushed, and hairs and tissue strands cross the injuries. The damage was probably inflicted with a metal rod with sharp edges.

Homicidal slashed wounds caused by knife; the length is greater than the depth, unlike stab wounds. The long tails are due to the knife rising from the skin, thus indicating the direction of the slash.

knife slash of the back showing regular scratches along the margin. This was inflicted with a ‘Rambo’ knife, which has deep serrations along the back edge that have somehow marked the skin on withdrawal.

A stab wound and the inflicting knife. The wound is slightly shorter than the width of the blade at the depth of penetration because of sideways gaping and the contractile elasticity of the skin.

Two knife wounds in the back. The wounds have a sharper lower edge compared to a rounder upper edge, due to a one-edged blade.

Multiple stabs on the back from the same knife, showing differing shapes and sizes.

A stab wound showing a unilateral ‘fish-tail’ split caused by the blunt back edge of the knife blade. This is sometimes bilateral due to tearing of the tissues. The other end of the wound is pointed due to the cutting edge of the blade.

Multiple stab wounds from the same knife, showing variations in the size and shape of the injuries. With multiple injuries, it is advisable to number each to facilitate easy reference in the autopsy report and when giving evidence in court.

A slashed facial wound from a knife, showing undercutting or ‘shelving’ on the edge nearest the mouth, indicating the angle of the knife relative to the surface. The tailed nature of the lower end also indicates that knife was drawn downwards across the face.

Homicidal stab wounds misdiagnosed by an attending doctor as ‘haematemesis or epistaxis’. The lower right wound clearly shows evidence of a single-edged blade. The wound in the left axilla is V-shaped because of the twisting knife.

A stab wound of the centre of the chest. Although each end of the wound is identical, the weapon was a single-edged kitchen knife. The end of the wound adjacent to the back of the blade has split making it impossible to say if a single- or double-edged knife was used. The sternum beneath was penetrated to reach the heart, so considerable force must have been used.

Three wounds from a single stab with a knife, which was in place when the body was discovered. The knife had entered obliquely through the inner side of the right breast, emerged into the cleavage and re-entered the mid-line. If the knife had not been in situ, interpretation could have been more difficult.

Homicidal stab wounds of the throat and head showing the pleomorphism of injuries caused by the same knife. The wound under the chin is V-shaped caused by twisting of the weapon; the large throat wound consists of several superimposed thrusts and over the manubrium there is a ‘tail’ caused by the tip of the knife slipping out of the wound on withdrawal.

Multiple homicidal stab and incised wounds inflicted with various kitchen utensils.

A wound over the eyebrow caused by impact from a broken drinking glass. Although this location is commonly the site of laceration from blunt blows, this injury is sharp-edged and has unbruised margins, indicating that it is an incised wound. There is an associated abrasion from non-cutting contact and there is bleeding into the upper eyelid, probably from gravitational seepage from the wound

Multiple homicidal stab wounds by closed scissors.

Defence injuries: bruising on the back of the hand in an attempt to fend off a blunt instrument in this case a metal poker that was used to inflict fatal head injuries. Such injuries confirm that the victim was conscious and active during the attack, and that it was not made covertly while the victim was unaware.

Defence wound on the back of the hand from trying to ward off the knife.

Typical defence injuries in a victim of a knife attack. In grasping the blade to deflect it, there have been cuts across the palmar surfaces of the finger joints and a slash between the thumb and forefinger, together with a cut at the base of the thumb.

Defence wounds of hand in attempts to ward off an assault with a meat cleaver.

Medico-Legal importance • Homicidal-occurs in any part of the body. produced by blows with hard and blunt weapon. • Suicidal-Very rare. • Accidental-Road traffic accidents, accidental fall from height. • Foreign bodies-Mud, gravel, oil etc.

Incised wounds • Its produced by sharp cutting instrumentsknife, razor, blade, swords, chopper, axe etc. Features: • Edges are regular, clear cut, retracted and averted. • Except in neck and scrotum-edges are inverted. • Spindle shaped wound, maximum widening in the central part. • Length is greater than the breadth. • Breadth is greater than the thickness of the cutting blade.

• Gaping is greater if underlying muscles are divided across or cut obliquely. • Haemorrhage is excessive due to the cleat division of blood vessels. • Half severed artery bleeds more as they can neither retract nor contract. • Edges of wound may be irregular when skin is loose and if cutting edge is blunt.

Weapon • Incised wound means use of sharp cutting weapons. • Bevelled cuts and chop wounds suggest use of heavy or moderately heavy sharp cutting weapons.

Defence wounds • Defence wounds result from the immediate and instinctive reaction of the victim to save himself, either by raising the arm to prevent the attack or by grasping the weapon. • If the weapon is blunt, bruises and abrasions produced on the forearms or backs of the hand. • If the weapon is sharp the injuries will depend upon the type of attack, whether stabbing or slashing. • If the weapon is single edged and grasped-single wound. Double edged-double wound.

Fabricated & Self-inflicted wounds • They are the wounds inflicted by a person on his own body. • Fabricated wounds-produced by a person on his own body or others body with consent. • To charge an enemy with assault or attempted murder. • To aggravate a simple injury.

• By the assailant to pretend self defence. • In theftsrobbery where servants of the house are involved, to get absolved from the crime. • By woman to bring a charge of rape against an enemy.

• Stab Wounds • • Forensic Importance • • Reflects sharp edge, not weapon type • No trace evidence • • Bleeds profusely • • Hemorrhage and air embolism • • They can be produced by any long thin object which impacts the body with sufficient force to penetrate. • The typical instrument is a knife, but any sharp pointed, or keen-edged object will work.

• Stab Wounds: Degree of Force • • The most reliable estimate of blade width is made from the deepest wound with the shortest skin surface length. • • It is easy to over-estimate the amount of force required to produce a stab wound. • • The depth of a wound is not generally an indication of the degree of force used

• Stab Wounds: Degree of Force • • The most critical factor is the sharpness of the point of the instrument; relatively little force is required to produce a stab wound provided a knife with a sharp point. • • After clothing, the skin offers the greatest resistance to penetration; once this is overcome, then the blade easily cuts into deeper tissue.

• Stab Wounds: Degree of Force • • The penetration of bone does imply a significant degree of force. • • The tip of the blade may break off when driven into bone and should be recovered for matching with the weapon. • • In estimating the force exerted by an assailant, consideration should be given to the possibility of counter pressure by the victim, e. g. running or falling forwards.

• Stab Wounds: Length of Weapon • The depth of the wound (the length of the wound track, provides some indication of the length of the stabbing instrument). • • The wound track length may be less than the length of the instrument if the weapon was not thrust into the body to its full length. • The wound track can be longer than the knife if there is force compressing tissues.

• Stab Wounds: Clothing • • Cuts on the clothing should be noted and correlated with injuries to the body. • • More than one cut on the clothing may correspond with a single injury to the body as a result of folds in the clothing. • • Cuts to the clothing may not exactly overlie corresponding wounds to the body. • • There may be stab or slash marks on the clothing without corresponding injuries to the body, e. g. "defense"-type slashes to the arms.

• Stab Wounds: Cause of Death • • Most deaths from stab wounds are homicides. • Homicidal stab wounds are usually multiple, since most wounds leave the victim capable of some resistance for a measurable time during which the thrusts are repeated. • • Single homicidal stabbings are often associated with drugged, drunk, sleeping, or otherwise partially incapacitated victims and are almost always aimed at the heart.

• Homicidal stab wounds to the chest are all likely to be deep, penetrating the chest wall, and more than one may be lethal. • • Stabs in the back strongly suggest homicide. • In cases of multiple scattered stabs, the larger the number the greater the certainty of murder. • • There is often a sexual motive to deaths with this type of "over-kill".