INJURY

Clinically its defined as solution or disruption of the anatomical continuity of any tissues of the body.

Legally under section 44 IPC, its defined as any harm whatever illegally caused to any person in body,mind,reputation or property.

Wound

Medico-legally include any lesion,external or internal,caused by violence,with or without breach of continuity of skin.

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. Fractures. Fire arm injuries.

Abrasions

Injuries involving superficial layers of the skin and are caused by

-Impact of an object.

-Fall on rough surface.

-Pressure of finger nails,teeth,muzzle of

a gun or by rope.

Abrasion

Tangential Compression

(friction/sliding/scrape) (crushing/pressure)

Linear Brush Patterned Non-Patterned

(scratch) (graze)

Impact Contact

Age of abrasionRecent abrasion appears bright red scab 12-24 hrs.Reddish brown scab 2-4 days.Healing process starts 4-7 days.Epithelium grows and dried scab falls 8-10 days.Absence of infection.

Antemortem Abrasions

Reddish brown colour.Margins are blurred due to vital reactions.

Postmortem Abrasions

Yellowish in colour.Translucent area.Margins are sharply defined.Absence of vital reactions.

Artifacts in Abrasion

By Ants.By Insects.By Animals.By Marine animals.

Medico-Legal Aspects

Site of impact and possibility of internal injury.

Identification of object causing the injury.Cause of injury.Direction of injury.Time of injury.

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. 5-7 days.

Bilirubin-Yellow colour.7-10 days.Normal colour of skin 15-20 days. Pigments are removed by phagocytes.

Age of the contusion

Colour changes.Histologically.Healing process depends on:

-Size and situation of contusion.

-Age and physique of the person.

-Presence and absence of disease.

Antemortem contusion

Sharp,well defined margins.Swelling of the tissues.Discoloration of the skin.Extravasation of blood into the true skin and

subcutaneous tissue.Doubtful cases-Microscopic examination.

Postmortem contusion

Can be produced with in 1-2 hrs after death. If body is decomposed it is difficult to

differentiate between antemortem and postmortem contusions.

Self inflicted contusion

Rare-can be inflicted by irritant substances like Marking nut,root of plumbago zeyloxica or rosea.

Can be differentiated by chemical analysis.

Homicidal contusion

Shape and size of contusion,indicates the weapon used.

Accidental contusion

Their position,arrangement,circumstances and surroundings.

Medico-Legal Aspects

Identification of the object.Degree of violence.Cause of injury.Time of injury.

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-IrregularFloor-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 injury-

dust,mud,gravels etc.Healing-Process delayed due to gross damage

and infection.Scars-Due to damage to skin and tissue.

Types of lacerated wounds

Split laceration:

Found in pats overlying bones-scalp,face,hands and lower limbs.

Due to perpendicular impact by blunt force.Due to crushing of skin between two hard objects. It simulates the incised wound.

Stretch laceration:Due to over stretching of skin and produces

flap.Due to blunt tangential impact-when head

strikes on the wind screen of the vehicle.Due to sudden deformity of bones after

fractures.

Avulsion wound:Degloving of skin over the impacted area

due to compression and grinding of underlying tissue.

Commonly seen in road traffic accidents and by machinery in heavy industries.

Tears laceration:Due to friction with irregular or pointed end

of a weapon or an object on the surface of the body.

Deeper at the string point than at the terminal.

Cut laceration:This type of lacerated wound is produce by

“not so sharp” edge of heavy weapon.Seen in chop wounds.Margins are not clear cut.Abrasions or contusions are seen on the

margins.

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 instruments-

knife,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.

By nature of the incised wound,weapon used can be identified.

Light sharp cutting weapons-razor blades,knife an produce incised wounds by striking,drawing or by sawing.

Drawing cuts-Deeper at start,gradually become shallow and at the end only skin is cut with scratch “Tailing of the wound”

The position of the accused and victim can be identified in homicidal cases,and suicidal cases which hand has been used.

Sawing cuts-Multiple at the beginning and only one deep cut wound called “Tentative or Hesitation cuts”

Bevelling cuts-When weapon is used oblique or tangential way over the body.

Heavy sharp cutting weapons-like swords,axes,choppers etc-wounds are greater and severe. Usually homicidal in nature.

Injuries caused by these weapons show signs of bruising over the edges and extensive damage to deeper structures and organs.

Incised wounds made by curved weapons like sickle, tangi etc will cause single wound when hit over the convex portion of body.

Weapons applied over the flat surface, it will make two wounds with intact of skin between these two wounds and they will be in the same line.

Medico-Legal importance

Homicidal-Any part of the body, commonly on the neck, head and trunk, also be found on the inner side of forearm or hand of victim while defending or protecting. ‘Defence Wounds’.

Suicidal-Found in the accessible parts by light weapons on the throat (cut throat wounds). Tail end of the wound indicates which hand has been used.

Accidental-Any part of the body hands, fingers during the handling of knife, razor blades etc.

Weapon

Incised wound means use of sharp cutting weapons.

Bevelled cuts and chop wounds suggest use of heavy or moderately heavy sharp cutting weapons.

Manner of use of weapon

Deep chop wounds and bevelling suggests striking by the weapon.

Tailing and hesitation cuts indicate drawing of the weapon.

Multiple superimposed or overlapping injuries are indicated by saw like movement of the weapon.

Direction of application of force

From the tailing and bevelling, the direction of application of force can be known.

The relative position of the victim and the assailant can also be known, by the direction of application of force.

Age of the wound or time since injury

In case of dead bodies-histological examination of tissue from the margin of the wound, gives the clue that the survival of time after injury.

Time since injury can be studied by the healing process.

When fresh- Bleeding is still present or fresh soft clot is adhered, margins are red, swollen and tender.

By 12 hrs- Blood clot and lymph dry up, margins are red and swollen. Histologically there is infiltration of leucocytes.

By 24 hrs- Proliferation of connective tissue cells and vascular endothelium for neo-vascularisation.

By 36 hrs- Fibroblastic infiltration and capillary network formation starts.

By 48hrs- Capillary network is completed. Fibroblasts run across the new vessels.

By 3-5days- Vessels are obliterated and thickened, wound heals and scar formation starts and advances.

By 6th day- Scar formation is completed. Scab over the wound falls off. After weeks and months, soft, tender, reddish scar becomes tenderless, whitish and firm.

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. (fictitious, forged or invented)

To charge an enemy with assault or attempted murder.

To aggravate a simple injury.

By the assailant to pretend self defence. In thefts\robbery 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 wound\Punctured wound

These are the deep wounds produced by the pointed end of a weapon or an object, entering the body.

These injuries generally caused by ‘sharp pointed piercing stabbing weapons-knives, dagger, bayonet, arrow, pick-axe, broken glass pieces.

A stab wound caused by a sharp pointed and cutting instrument has clean cut edges, have sharp angles at the two extremities.

The wound is wedge shaped if it is produced by instrument with only one cutting edge.

A sharp pointed and cylindrical or conical instrument produces a wound having a circular or slit like opening.

When the edges of the weapon are sharp, the wound produced is an ‘Incised penetrating wound’.

When the weapon edge is blunt, it produces a ‘Lacerated penetrating wound’.

When a stab wound enters into a body cavity-thoracic, abdominal, joint cavities ‘penetrating wound’.

When the wound pierces the body through and through it is known as ‘perforating wound’.

Features of punctured wound

Length of the external wound should correspond with the breadth of the blade of the weapon.

Entry wound length is little shorter than breadth of the blade or body of the weapon.

Exit wound also similar to entry wound.Breadth of the entry or exit wound should

correspond with the thickness of the part of the blade of the weapon. But it depends on the elasticity of the skin, direction of underlying muscle fibres and their intactness.

If the fibres are not cut, due to rigor mortis reduces the breadth-fibres are cut increases the breadth.

Depth is the greatest dimension of a stab wound produced by the length of the weapon introduced and its length and breadth by the breadth and thickness of the weapon respectively.

Sometimes wound may be greater than the length of weapon in the yielding parts.

Edges are retracted, clean or lacerated and bruised according to the weapon used.

Knives, daggers, bayonets and other sharp cutting weapons cause surface injuries will be an ‘Incised Wound’.

Pick-axe or horn of animals which have blunt edges-margins irregular, bruised and lacerated.

Shape of the wound of entrance in case of stab wound depends on the shape of the weapon and its edges.

Hilt marks are common when the weapon is pushed till the handle.

Haemorrhage is more internally than external wound.

Injury to the vital organs are common in stab wounds.

Concealed Punctured Wound

These are punctured wounds produced by needles, nails or pins.

Concealed parts of the body-nostrils, frontanella, fornix of the upper eyelids, axilla, vagina, rectum and nape of the neck.

Complications

Marked internal haemorrhage. Infection to the wound due to foreign

materials.Air embolism.Pneumothorax.Asphyxia due to inhalation of blood.

Medico-Legal Importance

Shape of wound indicates the type of weapon.The depth of the wound indicates the force of the

penetration.Direction and dimensions of the wound indicate the

positions of assailant and victim.Age of the injury can be determined.Position, number and direction of wounds can give

clue for manner of production-Suicidal, Accidental, Homicidal.

Fracture Fracture of a bone is defined as

disintegration or breakage of bone due to blunt force either directly or indirectly.

Direct fracture. Indirect fracture.

Direct Fracture Focal fracturesSmall force applied to a small area. Injury

to overlying soft tissue is minimal.Eg-forearm and leg, where two bones lie

adjacent to each other. While defending blows during an attack. ‘Tapping Fracture’.

Crush fractures It results from application of a large force

over a large area and is typically fragmented.

Injury to the surrounding soft tissue is usually extensive.

If two bones lie adjacent to each other, both are involved.

Eg- fracture of tibia and fibula in RTA.

Penetrating fracture It results from applications of a large force

over a small area.Eg- Bullet injury to a bone. Both tissue

damage and the comminuted type of fracture.

Indirect Fractures

Traction Fractures It results when a bone is pulled apart by

traction.Eg- Transverse patellar fracture due to

violent contraction, of this type of fracture due to sudden contraction of quadriceps.

Angular fraction It occurs due to bending of bone. The

concave surface of the bend is compressed, while the convex surface is put under traction resulting in breakage.

Rotational fractureFracture in spiral, when it is twisted.

Vertical compression fracture In this type fracture can be seen in long

bones with oblique fracture when hard shaft of the bone is driven into the cellous portion.

In RTA there has been a collision and knee has impacted violently against the dashboard.

Angular-Compression fracture

Here the fracture line is curved, with an oblique component due to compression and a transverse component due to angulation.

Repair and healing of the fracture

Healing of the fracture depends on the age and nutritional status of a person. Usually cancellous bone unites faster than cortical bone.

Haemorrhage phase.Proliferation phase.Callus phase.Consolidation phase.Remodeling phase.

In the Haemorrhagic phase, bleeding will be at the site of fracture.

In the Proliferation phase, a collar is formed around the fractured ends by proliferation of cells from periosteum and endosteum.

In the Callus phase, cellular elements give rise to osteoblasts and chondroblasts which produce a matrix of collagen and polysaccharide, impregnated with calcium.

In the Consolidation phase the callus is transformed into mature bone by 4-6weeks in children and in adults by 12-14weeks.

In the final, the Remodeling phase, matured bone will take place.

Medico-Legal Importance

Fracture of a bone constitutes grievous injury according to law.

The type of fracture can give the clue of causative force, whether direct, indirect, rotational or angular etc.

The site of fracture may help to indicate the cause of death.

Eg- fracture of hyoid bone suggestive of throttling.