Injury

Mechanical

Definition

• In law an injury is defined as " any harm, whatever illegally caused to any person in body, mind, reputation, or property ( Sec 44 IPC)
• In medicine an injury is a bodily harm produced by any means.
• Bodily harm is separately defined in Law in IPC-319. “Whoever causes bodily pain, disease or infirmity to any person is said to cause hurt”.
• A wound is defined as solution of natural continuity of skin, mucosa, or any of the tissues of the living body.
• Trauma is sudden & severe mental or physical injury

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Importance of Medico- Legal Examination of Injury

• If weapon is available , the measurement of length and breadth with direction of wound may give a clue to the depth and viscera affected.
• Bruising of an elbow in an accident may give a clue fractured ribs underneath.
• A medico-legal approach by reconstruction of the mechanism of production of an injury is just as important as a mere record of its presence and at times may lead to some innovation by which the injury can be prevented. Crash helmet, seat belt

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Raccoon Eyes

Classification of Injury

• Mechanical Injury
• Abrasion
• Bruise
• Fracture
• Wounds
• Incised
• Stab
• Lacerated
• Firearm & Explosive

Thermal injuries

• Injuries Due to Cold-
• Frost Bite
• Trench foot
• Immersion foot
• Injuries due to Heat-
• Burns
• Scalds

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Classification of Injuries

• Chemical Injuries
• Corrosive Acids
• Corrosive Alkalis
• Injuries due to:
• Electricity
• Lightning
• X-Ray
• Radioactive substances
• Legal Classification of Injuries IPC 319-320
• Simple
• Grievous

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Classification Based on Causes

• Living irritants through chemical poison and mechanical irritation
• Pathogenic microorganisms
• Animal Parasites
• Non living Irritants
• Physical- Trauma, foreign body, heat, cold, light, electricity, X-rays & other radiations
• Chemical- Strong acids & alkalis and all poisons

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Classification based on manner of Injury

• Suicidal
• Homicidal
• Accidental
• Natural
• Artificial
• Hesitant cuts
• Defence wounds

ABRASIONS�(Scratch, Graze, friction mark)

• Abrasions are caused by injury to the superficial layers of the skin produced by frictional contact of the skin with some sharp or rough object ( or by such an object coming in contact with the skin)
• An abrasion is a type of mechanical injury characterized by loss of superficial layer of skin (epidermis) or mucous membrane due to friction with some rough surface or point of sharp objects.

Types of Abrasions

• Scratch-
• Due to sharp & fine object passing across the skin, moving the surface layers in front of it and causing heaping up. This indicating the direction. Ex- finger nail scratches, due to thorns, sharp pin or point of knife.
• Grazes-
• When wider area of rough surface comes in contact with surface of skin it causes graze of varying depth. Direction is indicated by tag of tissue. Underneath tissue may be bruised if friction is associated with impact.

Types of Abrasions ( Cont.)

• Impression or impact abrasion-
• When the pattern of abrasion is copy of the object producing it . Because of elasticity of skin some distortion in the shape may be present but identification of the object may still be possible- Radiator grill, Tread of the car tyre, or lashes with a whip ,marks caused by teeth in bite may have peculiar characteristics which matches with bite of the accused.
• Pressure abrasion (Ligature Mark)
• Caused by linear pressure upon the skin accompanied by movement. Commonly seen in hanging , strangulation or tying of a limb . The differentiation of antemortem from post-mortem ligature mark may be impossible , as when dry both type will have similar brown appearance. Sometimes vital changes in form of haemorrhagic spots may be seen at the edges of the antemortem lesions.

Medico-Legal Importance of Abrasions

• They may be the only external signs of a serious internal injury
• Patterned abrasions connect injury with object which produced it.
• Some times their site may suggest the nature of the crime- Breast bite, abrasion on thigh.
• Abrasions are mostly accidental , they may also be homicidal but are rarely suicidal
• Abrasions are generally simple hurt but may be grievous.

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Abrasion to be differentiated from

• Excoriations of the skin by excreta- In infants some excoriations may be present in the napkin area before death.
• Marks produced by insects after death - they are dry, brown with irregular margins and are usually seen on the eyes, nostrils, angles of mouth, ears, armpits, groin, scrotum, anus or where ever the parts are slightly moist. Fish may also produce similar injuries which are white wet.
• Pressure sore- Bony prominence, softening of tissue Hospitalisation or bed ridden.
• Perimortem abrasions look alike , even under microscope. Differentiation difficult in very superficial abrasion after the decomposition is advanced.

Difference Between Antemortem & Post-mortem Abrasions

Age of Abrasion

• The exact age cannot be determined. Fresh – Bright Red with some serosanguinous exudation
• 12-24 hours- Lymph and blood dries up leaving bright red scab
• 2-3 days - reddish- brown scab
• 4-7 days- Brownish black scab. Epithelium grows and covers the defect under the scale but may bleed on trying to remove scab
• After 7 days- Scales dries, shrinks and falls off from periphery.

Bruises �(Contusion or Ecchymosis)

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• Bruise is a discolouration of skin due to an injury caused by a blunt force resulting in to extravasation of blood into the tissue without solution of the continuity of the skin or mucous membrane.
• Haematoma is formed when large blood vessel is injured causing haemorrhage of some size forming a tumour like swelling under skin.

Causes

• Spontaneous- purpura , scurvy, leukaemia
• When a blunt force is applied to body or when a moving body strikes a stationary blunt object, then apart from other injuries like abrasion and laceration, bruise might result. It is due to crushing of small blood vessels like capillaries with extravasation of blood in to the affected tissue. The blunt force should be such as not to cause tearing of the covering skin or mucus membrane because then the injury is called laceration .ex- fist, stones stick, whip, bar, foot etc.
• Degree of violence required to cause bruising vary from firm gripping to heavy blows.

Changes in Bruise

• Swelling more in loose tissue like eyelids and scrotum or labia due to leaking of more blood. Bruising much less in scalp, palm or sole
• Swelling increases in size as the time passages up to 24 - 48 hours after which it gradually starts regressing and disappears depending on size in one to two weeks.
• Colour changes in skin determines age of the bruise 
• Oxygenated blood which leaks into tissue is bright red initially and up to the period fresh blood is added(up to 24 hrs) the blood retains its oxygen and looks bright red.

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Changes in Bruise (Cont.)

• With deoxygenation blood becomes dusky purple or black and is seen through the skin as such.- 2-3 days (Reduced Haemoglobin)
• 4^th day –Bluish black to brown (Haemosiderin)
• After 5-6^th days- as the RBCs are broken down haemoglobin is liberated and broken down into iron and the pigment(haematoidin) the colour changes into dark green which gradually lightens its shade and become light green.
• After 7-12 days- as the iron is removed first the colour looks yellow(Bilirubin)
• 14th-15th days- Yellow gradually faints and disappear.

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Factors Modifying the Appearance of Bruise

• Because the inflammatory process starts from the periphery where new blood vessels grow and remove the tissue debris and blood pigments the colour changes start from periphery and proceed towards the centre which is touched last.
• Causative Agent- Harder the weapon greater the bruise.
• Amount of violence- Greater the violence more the bruising
• Absent if hit with yielding substance like sand bag

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Factors Modifying Bruises

• Superficial bruises appear at once
• Deep bruises visible one to two days later or may not appear on surface.
• Site of appearance of bruise may shift due to gravity shifting of blood from the site of injury.
• Discoloration will be more marked after the passage of time
• Therefore it is always advisable to re-examine the body 24 hours later for bruises ("finger tip" indicating struggle or restraint) for bruises produced at the time of death may show little swelling and less extravasation .

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Cont.

• Routine incisions should be made at autopsy over the common sites such as knuckles , forearms, elbows , shoulder , hips , buttocks back, knees, calves. If the victim survives they will be more marked.
• In living persons who have been assaulted a second examination after an interval of one or two days should be done for bruising originally indicated only by tenderness on pressure and slight swelling may become visible.

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Cont.

• Covering with cloth reduces bruising and it may be absent if body covered with thick rug , blanket or quilt at the time of assault.
• Infants and old people bruise easily.
• Infants - skin loose, delicate or plenty of subcutaneous fat
• Old people- loss of subcutaneous fat and poorly supported blood vessels.
• Sex- Women bruise more easily especially when they are obese because of subcutaneous fat.
• Texture and colour of skin- Fair skinned persons bruise easily . It is also easily seen in fair skin.

Effect of Diseases

• Natural disease-
• Hypertensive and with degenerative diseases of cardio vascular system tend to produce more extensive extravasation of blood, and because of impaired circulation, absorption is slower, with the result that colour changes will be delayed, and histologically modified. Fresh looking bruise may be seen overlying a 10 days old fractured femur.
• Some blood diseases, vitamin deficiency and liver damage may accentuate ecchymoses by delayed clotting and bleeding time.

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Patterned Bruise

• Bruise is usually round but it may indicate the nature of the weapon used-
• Solid body ( hammer or fist)
• End of thick stick - round but elongated if length of stick hits.
• Whip- elongated curves over prominences and may encircle the limb or body . Seen as two parallel lines distance between which gives the diameter of whip . End of bruise is abraded and finer.
• Cane - similar but does not encircle
• Straps , belts, chains- give definite imprint
• Ligature may produce a patterned bruise

Cont.

• Contact injuries with firearms - may indicate outline of muzzle
• Motor car accident may show bruise like grill mark
• Suction or biting or sexual assaults- give elliptical patterned bruise and teeth pattern may be present.

Bruise to be differentiated

• From hypostasis
• An incision on site will reveal presence clotted blood in the tissue in case of bruise
• Blood will ooze out from cut ends of the vessels in PM lividity
• From Post mortem bruises –
• Appreciable bruise does not occur 2 minutes after death. Small bruises may be produced using great violence
• Post mortem bruise restricted to bony prominences
• Artefact simulating bruise may occur in neck during removal of tongue
• In case multiple injuries are caused in perimortem period or if there is advanced decomposition then status of some injuries may be difficult to decide.

Difference Between Suicidal, Homicidal and Accidental Bruise

• Bruises caused by a blunt weapon are not as a rule self inflicted.
• To bring false charges, juice of marking nut, root of Plumbago zeylanica, or Plumbago rosea is applied on skin.
• Colour dark brown, margins covered with tiny vesicles and surrounding skin red and inflamed.
• Similar stains found on tip of fingers and nails.
• A presence of mud, sand , Grease or oil may give an idea of accidental origin .

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Medico-Legal Importance

• Bruise simple injury but contusion of heart may cause death.
• Large number of bruises may cause death by shock and internal haemorrhage. A contusion may contain 10-20 ml or more blood.
• Patterned bruise may connect victim with offender.
• From age of bruise the time of assault can be estimated .
• Degree of violence may be ascertained from bruises.
• The character/ site of bruise may reveal the manner of assault , finger tip bruise, teeth marks, nail marks on inner side of thigh.

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Lacerations �(Tears or Ruptures)

• It is tear or split caused by the effect of blunt force on tissue.
• It is a wound caused by application of blunt force.
• Depending on the severity of the impact a blunt force might cause bruise or laceration. And if there is associated friction then there may as well be an abrasion

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Types of Lacerations

• Split laceration –
• By crushing of the skin between two hard objects. Ex.- scalp laceration , cut eye brow of the boxer, lacerated chin of motorcyclist .
• Stretch laceration –
• Due to over stretching of skin Ex- when a weight passes over a limb or where bone is bent and broken. There is over stretching of skin until a point is reached where the skin must break producing a flap or tear.
• Avulsion ( Grinding compression) –
• A weight may produce avulsion of skin from under lying tissue underlying tissue is also crushed. Ex- lorry wheel passing over the body or a limb

Types of Laceration

• Tears-
• Caused by door handle of a car or a protruding hinge. It really an over-stretching action similar to already described ‘Stretch’ which is caused by irregular or sharp objects.
• Cut lacerations-
• Are inflicted by a heavy edged instruments such as a chopper or hatchet .
• Puncture laceration-
• Caused by a blunt pointed object piercing tissue to a varying depth. In such cases the skin is cut with bruising at edges and hairs may be forced into the wound.

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Lacerations

• Single lacerated wound does not bleed externally, but multiple closely placed lacerated wounds bleed but less than in incised wound.
• Margins irregular and bruised may also be abraded
• Hairs are not cut but may be crushed
• Lacerated wounds are more painful than incised wounds
• Chances of infection in lacerated wound is far more including that of tetanus and gas gangrene
• Healing of large lacerated wounds is slow

INCISED WOUNDS

• Incised wound is caused by a sharp weapon in which margin of the wound is clean cut regular and the surface length is more than width or depth
• Incised wounds may be caused by any object with a sharp edge ( either linear or pointed) ex- knife, razor , fragments of glass etc.
•  Edges - clean cut , well defined and usually everted Edges may be inverted if a thin layer of muscle is adherent to skin( scrotum)
• Size of incised wound has no relation with size of weapon .

Character of Incised Wound

• Shape- Spindle shaped because of greater retraction of edges at the centre. The gaping is more if underlying muscles cut transversely or obliquely and less if cut longitudinally.
• Haemorrhage- as vessels are cut cleanly the bleeding is more
• Direction- incised wounds are deepest at their commencement as more pressure is exerted on knife at this point. Gradually the incised wound ends in tailing of wound which is superficial incision of skin only which becomes finer as the end is approached.
• Bevelled - if the blade of weapon enters obliquely , one edge is bevelled at the expense of other and if the blade is nearly horizontal a flap wound is caused bevelling can be produced by a sharp weapon only.

Timing of an incised wound

• After 12 hours- edges red and swollen adherent with blood and lymph with leucocytic infiltration.
• After 24 hours- Scab of dried blood covering the wound. Proliferation of vascular endothelium and connective tissue cells seen microscopically.
• After 36-48 hours- capillary network complete. Fibroblasts running at right angles to the vessels
• After 3-5 days- Vessels show thickening and obliteration.
• Healing by first intention takes place in a week

Puncture�(Stab Wound)

• Puncture wounds have greater depth than their surface length or breadth and are caused by piecing or stabbing instruments having sharp pointed ends.
• Penetrating- puncture wounds are called penetrating wounds when passing through the tissue these enter a cavity of the body namely thorax, or abdomen.

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Character of Puncture Wounds

• Perforating wounds- when the weapon enters the body or a part on one side and comes out on the other side then the puncture wound is called perforating wound
• There are two wounds with single blow.
• Wound of entry- larger than exit with inverted edges
• Wound of exit- smaller with everted edges.
• Puncture wounds Take the shape of the weapon causing it
• Wound is elliptical in shape, margins are clean cut regular if caused by a pointed knife or dagger
• Margins may be abraded and bruised if caused by a sword or bayonet of a rifle.

Characteristics of Puncture Wounds

• Surface length- Is usually slightly less than the width of the weapon up to which it has been driven because of elasticity of the skin. Sometimes length is more if wound is enlarged by movement while withdrawing the weapon.
• Depth of the puncture wound is usually more than the length of blade up to which it has pierced in abdomen, elsewhere it is equal or less.
• Full penetration is confirmed if mark of hilt is present on sides of margin of the wound.
• In puncture wounds external bleeding may be negligible with even fatal internal bleeding.

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Medico-legal Aspects

• Suicidal stab wounds are found on accessible areas of body.
• Common site chest over heart or upper abdomen.
• Direction - upwards, back ward and to the right.
• Stab wounds are usually homicidal
• May be in inaccessible area of body
• Multiple wounds
• May have any direction but usually from above downwards and if by a Rt handed person then from left to right (On front of body) and from right to left if by a Lt handed person.
• Accidental - less common than homicidal. It is due to falling from height or traffic accident usually due to blunt pointed objects.

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Other puncture wounds�

• Lacerated Puncture Wound
• Concealed Puncture Wounds
• These injuries may not be detected unless carefully looked for though they may be fatal.
• Caused on concealed parts of the bodies like axillae, nostrils, fontanelle, nape of neck, vagina, rectum etc.
• Defence wounds-
• Are caused in trying to ward off the attack and are found on hands and arms which attempt to intervene.
• Tentative or Hesitant Cut

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Fracture of Bone / Tooth�(FRX or Fx, F_x, or #)

• Latin word for bone is ‘Os’. There are 270 bones at birth. 206 bones in adults. Femur largest, Stapes smallest
• Fracture is damage in the continuity of the bone caused by.
• High force impact or stress
• Minimal trauma injury in pathological fracture ( osteoporosis, bone cancer, or osteogenesis imperfecta.)
• A bone fracture may be diagnosed based on the history given and the physical examination performed. 
• Radiological imaging is performed to confirm the diagnosis
• Radiographic examination of the nearby joints is indicated in order to exclude dislocations and fracture-dislocations. 

• TRAUMATIC FRACTURES- Types
• Closed fracture:-  overlying skin is intact
• Open fracture/ compound fracture:- associated external wound communicating with fractured bones
• Linear fracture:- that is parallel to the bone's long axis
• Transverse fracture:- fracture line runs at a right angle to the bone's long axis
• Spiral fracture:- A fracture where at least one part of the bone has been twisted
• Comminuted fracture:- broken into several pieces.
• Impacted:- bone fragments are driven into each other
• Greenstick fracture:- Seen in infancy and childhood when due to softness the bone bends and breaks only on outside like a green stick when bent.
• Oblique fracture:- A fracture that is diagonal to a bone's long axis (more than 30°)
• Avulsion fracture- A fragment of bone separated from main

Healing Process

• 1. Reactive phase
• i. Following Fracture inflammatory phase 24-48 hrs
• ii. Granulation Tissue formation ( 2 to 3 Weeks )
• 2. Reparative phase
• iii. Soft Callus/ Cartilage formation- 3 to 6 Wks
• IV Hard Callus/Lamellar bone- 6 to 12 Weeks
• 3. Remodeling phase
• v. Remodelling to original bone contour and strength:- 3-5 years
• Factors affecting healing
• Adequate nutrient intake, Age, Bone type, Infection, drug therapy, and pre existing bone pathology

Medico- Legal Aspect

• All fractures are Grievous Hurt

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