WOUNDS AND INJURIES

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WOUNDS AND INJURIES
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Wounds and injuries
DEFINITION Disruption of the normal structure of
tissues caused by the application of force.
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Wounds and injuries
Legal definition of a wound a wound is where the
whole skin is broken, the continuity of the skin
broken. An abrasion of the surface is not
sufficient. Splits of the inside of the mouth
are included but not fractures or internal
injuries if the overlying skin is intact.
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Wounds and injuries
A wound implies a deliberate action while an
injury can be caused accidentally.
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Interpretation of injuries
This is the most important part of the forensic
examination The nature of the agent(s) causing
the injuries may be identified in general terms
e.g. due to a blunt object or a sharp object.
The pattern of the injuries on the body may
help in deciding the circumstances in which the
injuries occurred, accident, suicide or
homicide.
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Describing injuries
1.The nature of the wound, ie whether it is a bruise, abrasion or laceration etc
  2.The wound dimensions, eg length, width, depth etc. 3.It is helpful to take a photograph of the wound with an indication of dimension (eg a tape measure placed next to the wound), 4.Measurements to be taken of the wound as it appears first, and then with wound edges drawn together
 
 
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Describing injuries
 
 
  5.The position of the wound in relation to fixed anatomical landmarks, eg distance from the midline, below the clavicle etc
  6.The height of the wound from the heel (ie ground level) - this is particularly important in cases where pedestrians have been struck by motor vehicles
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Blunt force injuries

• Abrasions
• Bruises
• Lacerations

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Injuries due to sharp or long instruments

• Incised wounds
• Stab wounds

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Bruise

• Crushing of tissues
• epidermis uninjured
• connective tissue crushed
• small vessels ruptured and bleed into tissues
• common in young and old, haematological problems
• falls, assaults

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Bruises/ Contusions

• Bruises are caused by blunt trauma / injury to
  tissues, resulting in damage to blood vessels
  beneath the surface.
• Blood leaks out ('extravasation') into
  surrounding tissues from damaged capillaries,
  venules and arterioles.
• Bruises may be surface bruises, or deeper within
  tissues or organs.

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Bruises/ Contusions

• Unlike abrasions, the characteristics of the
  object causing a bruise cannot easily be
  determined, because blood tends to spread out in
  a diffuse manner from the site of injury,
  particularly along fascial planes.
• 'shifting' of bruises after time. For example,
  from faace or scalp to neck
• Bruises may also 'appear' after some days due
  again to the same phenomenon of blood tracking
  along tissue planes, and pathologists often
  re-examine a body again to look for such bruising.

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Bruises/ Contusions
Intra-dermal bruises, however, provide an
exception to this general rule, as they are
superficial - lying just under the epidermis. In
this case, there may be good correlation between
the bruise seen and the characteristics of the
causative object e.g. tramline bruises.
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Bruises/ Contusions
  Ecchymoses/ purpura - smaller than a few millimeters
  petechiae - pinpoint bruises(usually due to venous engorgement, e.g. in asphyxia, or in defects in blood coagulation such as Disseminated Intravascular Coagulation (DIC)). Senile purpura flat purple bruises in elderly
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Bruises/ Contusions
A blow from an object may give rise to a
combination of injuries, such as a bruise with an
abrasion etc, and different parts of the body are
more susceptible to bruising than others. For
example, the skin over the eyelids bruises
easily, whilst the tougher palmar surface or
plantar surface rarely bruises, unless severe
direct trauma e.g. fall from a height or torture.
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Bruises/ Contusions
The positioning of bruising is significant e.g.
multiple rows of spherical/ disc shaped bruises
may be seen when an attempt is made to strangle
someone with bare hands (manual strangulation).
The bruises are caused by the attacker's
fingertips pressing into the skin.
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Bruises/ Contusions
'Tramline' bruises Consist of two parallel
linear bruises separated by a paler, undamaged
section of skin. This type of injury occurs when
the skin is struck with a rod shaped object,
which squeezes blood from the vessels at the
point of inpact, thus emptying them and
preventing them from leaking blood. The edges of
the wound are stretched, and blood vessels are
torn, causing blood to leak into the surrounding
tissues. A similar phenomenon is seen when the
injury is caused by a hard spherical object, such
as a squash ball !
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Abrasions

• Surface injury
• graze or scratch
• rough surface striking the body tangentially
• crushed epidermis, pressure or imprint abrasions
• examples ligature mark, fingernail scratches,
  tyre marks, ground or gravel injuries e.g. grazed
  knees

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Abrasions
An abrasion is a superficial injury, commonly
known as a 'graze' or 'scratch'. This type of
wound damages only the epidermis (uppermost skin
layer), and should not therefore bleed.
However, abrasions do usually extend into the
dermis causing slight bleeding.
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Abrasions
Abrasions are commonly caused by a 'glancing'
impact across the surface of the skin, If the
force is directed vertically down onto the skin
surface it may be termed a 'crush' injury. These
wounds are seen where an object has struck the
skin (eg a kick), or where the injured person has
fallen onto a rough surface, such as road.
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Abrasions
Abrasions may be 'linear', a 'scratch' If
broader surface is affected, it is called a
'graze' or 'brush abrasion' (eg where a
motorcyclist is thrown from their vehicle, and
comes into contact with the road surface in a
skidding fashion). Such an abrasion often covers
a relatively large area of skin, and is often
called a 'friction burn.
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Abrasions
If the surface of an abrasion is examined
closely, for example with a hand-held magnifying
glass, the direction of force can often be
determined, from the torn epidermis. Strands
are drawn towards the end of the injury, and are
'heaped up'. The edges of the wound may also be
ragged and directed towards the end of the wound.
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Abrasions
Of particular importance in the forensic setting
is the fact that abrasions can retain much of the
surface characteristics of the object that caused
the wound. For example, there may be a
patterned abrasion caused by an element of a
vehicle involved in a 'hit-and-run' (such as that
made by a radiator grill or bumper), and if the
abrasion has been fully documented and
photographed (with a scale) and the suspected
vehicle is subsequently recovered, the two may be
matched up.
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Lacerations

• Breach in epidermis and dermis
• crush injury
• common where skin stretched over bone, scalp,
  face and shins
• margins bruised and abraded
• tissues not cleanly divided, tissue bridges
  across base of wound
• bleed profusely
• falls, kicks and blows from object

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Lacerations
These wounds are commonly known as 'gashes,
tears or cuts' of the skin. The skin surface is
split or torn following blunt trauma, and the
force causes the full thickness of the skin to be
damaged. Lacerations therefore bleed profusely.
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Lacerations
Areas of the body that are commonly the site of
lacerations are those with underlying bony
support, such as above the eyebrows, on the scalp
and face, or over the knees etc, whilst they are
less common on areas of the body that are softer
such as the buttocks. Contact with motor
vehicles may also cause splitting of the skin due
to grinding type movements over the surface, the
most severe being a degloving injury.
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Lacerations
Lacerations have ragged wound edges,
as they have been torn apart and not neatly
incised as in a surgical wound. scalp
lacerations sometimes resemble incised wounds
when they have been caused by a regular shaped
object. If the wound is examined closely the
ragged edges can be visualised, along with
crushing and bruising of the margins, hairs
driven into the tissues and tissue strands
crossing the depth of the wound (nerves, fibrous
brands, vessels)
 
 
 
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Stab wounds

• Caused by long object
• penetrate body
• small surface wound, depth varies
• shape depends on object penetrating

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Stab wounds
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These are wounds where the depth of injury is
greater than the length. They penetrate more
deeply than slash wounds and tend to come into
contact with vital organs in the chest and
abdomen Stab wounds are caused most obviously
by knives, but are also caused by bayonets and
swords, as well as scissors and even blunter
instruments such as screwdrivers.
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Stab wounds
muscle and skin contracture around the wound often obscures the size of the knife blade
  the size of the wound depends upon the depth of penetration of the knife, and whether, for example the parallel section of the knife has been reached (ie near to the hilt of the knife)
  if the blade is 'rocked' in the wound (ie either the assailant moves the knife around, or the victim moves in relation to the knife), the wound is longer than if the knife is inserted in and out rapidly and in the same direction
  irregular or 'V' shaped wounds arise when the knife is twisted in the wound
  most knives are single edged, and have a sharp cutting surface whilst the back of the blade is blunt. The wound may be sharp at one end, and blunt at the other. Unfortunately, this is not always the case, as the blunt edge of the knife may split the skin, and resemble a double edged knife wound.
muscle and skin contracture around the wound often obscures the size of the knife blade
  the size of the wound depends upon the depth of penetration of the knife, and whether, for example the parallel section of the knife has been reached (ie near to the hilt of the knife)
  if the blade is 'rocked' in the wound (ie either the assailant moves the knife around, or the victim moves in relation to the knife), the wound is longer than if the knife is inserted in and out rapidly and in the same direction
  irregular or 'V' shaped wounds arise when the knife is twisted in the wound
  most knives are single edged, and have a sharp cutting surface whilst the back of the blade is blunt. The wound may be sharp at one end, and blunt at the other. Unfortunately, this is not always the case, as the blunt edge of the knife may split the skin, and resemble a double edged knife wound.
muscle and skin contracture around the wound often obscures the size of the knife blade
  the size of the wound depends upon the depth of penetration of the knife, and whether, for example the parallel section of the knife has been reached (ie near to the hilt of the knife)
  if the blade is 'rocked' in the wound (ie either the assailant moves the knife around, or the victim moves in relation to the knife), the wound is longer than if the knife is inserted in and out rapidly and in the same direction
  irregular or 'V' shaped wounds arise when the knife is twisted in the wound
  most knives are single edged, and have a sharp cutting surface whilst the back of the blade is blunt. The wound may be sharp at one end, and blunt at the other. Unfortunately, this is not always the case, as the blunt edge of the knife may split the skin, and resemble a double edged knife wound.
  They are usually slit-like When the object is removed the skin contracts slightly, leaving a wound that is slightly shorter than the blade width. The centre of the wound often widens.
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Stab Wounds
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Incised wound

• Due to sharp instruments
• length greater than depth
• wound margins uninjured
• deep tissues cleanly cut
• e.g. surgeons incised wound

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Incised wounds
Slash Wounds These are wounds where the length
is greater than the depth, eg a slice wound
across the skin. If the wound involves major
blood vessels, it can be life threatening, but in
general, they are not as serious as stab wounds.
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Other injuries

• Weals
• Glass injuries
• Axe injuries
• Thermal injuries
• Firearm injuries
• Defence injuries
• Self-inflicted injuries

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Miscellaneous

• Weals - triple response
• defence injuries - assaults arms, hands, legs
• self inflicted - haphazard on arms or body in
  mental disorders
• tentative injuries - suicide attempts short,
  shallow wounds on wrists or neck

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Age of injuries

• Colour changes in bruises - purple to yellow
• scab formation in abrasions
• scabbing and scarring of laceration
• histological examination of tissues

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Bruises change colour over time, because of the
degradation of haemoglobin in the blood. However,
the timescale of this degradation is not fixed,
and it is therefore possible only to give a rough
estimation of the age of the bruise. Colour
changes are from dark blue or purple to blue,
brown, green and yellow
 
 
 
 
 
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Age of bruises
Bruises change colour due to degradation of
haemoglobin Timescale of this degradation is not
fixed Possible only to give a rough estimation of
the age of the bruise. Colour changes are from
dark blue or purple to blue, brown, green and
yellow In general, small bruises on an otherwise
fit and healthy person, could pass through the
spectrum of colour changes between 72 hours and 1
week. The more extensive, or deep seated the
bruise, the longer it will take to dissapear. If
a bruise is brown/ green or yellow it is likely
that the injury is at 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.
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Death from injuries

• Haemorrhage
• damage to vital structure
• shock
• infection
• pulmonary thromboembolism
• acute tubular necrosis
• fat embolism

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The rounded clear holes seen in the small
pulmonary arterial branch in this section of
lung are characteristic for fat embolism. Fat
embolism syndrome more commonly due to trauma
with long bone fractures. It can also be seen
with extensive soft tissue trauma, burn injuries,
severe fatty liver, and very rarely with
orthopedic procedures.
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An Oil Red O stain demostrates the fat globules
within the pulmonary arterioles. The globules
stain reddish-orange. The cumulative effect of
these gobules throughout the lungs is similar to
a large pulmonary embolus, but the onset of
dyspnoea is usually 2 to 3 days following the
initiating event, such as blunt trauma with bone
fractures.
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The capillary loops of this glomerulus contain
fat globules in a patient with fat embolism
syndrome.
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With cerebral fat embolism syndrome, there is
loss of consciousness. Note the multitude of
petechial hemorrhages here, most in white matter.
Cerebral oedema and herniation may follow. Few
persons with a history of trauma will develop fat
embolism
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Seen here with Oil red O stain in a peripheral
cerebral artery branch are globules of lipid.
This is fat embolism syndrome. Treatment is
supportive.