MECHANICAL INJURIES 2- jps

MECHANICAL INJURIES: 

MECHANICAL INJURIES DR. JINESH P. S. 16/08/2011

CONTENTS: 

CONTENTS LACERATED WOUND & SIGNIFICANCE INCISED WOUND & SIGNIFICANCE PUNCTURED WOUND & SIGNIFICANCE REFERENCES

LACERATED WOUND: 

LACERATED WOUND A TYPE OF MECHANICAL INJURY WHERE THERE IS A RUPTURE OR TEAR OF SKIN OR DEEPER TISSUES, OR BOTH , DUE TO APPLICATION OF BLUNT FORCE Three dimensional Often have abraded margins & irregular contused edges In external - as blood vessels are crushed, haemorrhage is usually not severe In internal – haemorrhage from ruptured viscera may be severe & fatal

LACERATED WOUND: 

Foreign particles frequently present Interior contains bridging strands Depth may not be uniform through out produced by any one or more of the following means Passive agent like ground Vehicles Blunt weapons LACERATED WOUND

CAUSES OF DFF. TYPES : 

CAUSES OF DFF. TYPES Configuration of the object delivering the force Type of the tissue Areas of the body involved Velocity of the offending weapon

TYPES: 

TYPES Tears Split (incised –looking laceration) Stretch Avulsion (grind laceration) Crushing Cut laceration Patterned laceration Post mortem laceration

TEARS: 

TEARS Results from tearing of tissues due to a relatively sharp force, which is not sharp enough to incise Caused due to projecting object Do not generally corresponds in shape or size to the weapon producing Bruised tear (contused laceration) - impact produces bleeding into the surrounding tissues Scraped tear (abraded laceration) - margins of the laceration are denude of the epithelium

TEAR - MECHANISM: 

TEAR - MECHANISM

CUT LACERATION: 

CUT LACERATION Results from cutting action of a weapon which is not very sharp (broken glass piece) Profound & distinct contusion of edges Some hair ‘ ll be driven into interior

SPLITS: 

SPLITS Skin gets split due to compression bet weapon & underlying bone Split laceration looks like incised wound – apparent incised wound Hand lens examination reveal contusion of edges & bridge of tissues Bruising seen surrounding edges Common area involved – scalp, lower jaw, shin, eye brow, iliac crest

STRETCH: 

STRETCH Skin gets stretched to a breaking point resulting in a laceration at that site In run over by motor vehicle Skin is split off & whole skin may comes off Hanging skin indicates run over

AVULSION: 

AVULSION Also known as degloving or destocking of skin Skin overstretched In run over by motor vehicle – s kin & wheel moves together & skin comes off Skin is separated from underlying tissue & hangs loosely

CRUSHING: 

CRUSHING Wheels stays over skin & cause grinding compression, crushing underlying tissue & bones with partial or total amputation Associated with avulsion & stretch laceration More chance of fat embolism

PATTERNED LACERATION: 

PATTERNED LACERATION Rarely reproduce shape of injuring object But – hammer blow to the scalp Exact size of striking surface ‘ ll not corresponds

LACERATION OF INTERNAL ORGANS: 

LACERATION OF INTERNAL ORGANS Blunt force on chest & abdomen – compressive force propagated internally External injury may be absent or minimal Kicking or fisting on abdomen can produce rupture of liver

LIVER LACERATION: 

LIVER LACERATION

POSTMORTEM LACERATION: 

POSTMORTEM LACERATION Usually produced by terrestrial or aquatic animal action on corpses (rat, fish, crab) Vital reaction is absent Edges shows evidence of ‘nibbling’ or ‘gnawing’ Running vehicle or train can cause extensive postmortem laceration

REPAIR & HEALING: 

REPAIR & HEALING Often get infected, delays healing Don’t exhibit uniform healing pattern, age estimation difficult Healing by second intention

REPAIR & HEALING: 

Debris removed by phagocytosis Filling of defect by granulation tissue Lost tissues are repaired Epithelium regenerates & cover surface Permanent scar Time frame depends upon extent & severity REPAIR & HEALING

AGE OF THE LACERATED WOUND: 

AGE OF THE LACERATED WOUND UNSUTURED Inflamed skin edges 12-24 hrs Appearance of infection 36-48 hrs SUTURED Inflamed edges 12-24 hrs Edges can be easily separated 1-3 dys Firm union 3-5 dys Red linear tender scar 7-10 dys Pale firm nontender scar More than 4 wks

MEDICOLEGAL SIGNIFICANCE: 

MEDICOLEGAL SIGNIFICANCE Commonly seen above bony prominence May be accidental or homicidal, self inflicted are rare Foreign particles help to identify causatives Type of laceration provide a clue to nature of occurrence In avulsion – direction of force can be ascertained Site may give clue about cause of death (laceration of internal mucosa of lips – smothering) In face constitute grievous hurt

INCISED WOUNDS: 

INCISED WOUNDS A clean division of tissue by a sharp cutting instrument Force is delivered over a very narrow area, corresponding with the cutting edge of the blade Egs – knife, razor, dagger, Incised wounds caused by heavy cutting weapon ‘ ll have bevelled edges – chop wounds Egs – chopper, axe, sword

INCISED WOUNDS: 

Types: Slash wounds: Length > depth. Generally NOT as serious as stab wounds unless involves major blood vessel. Stab wounds: Depth > length. More SERIOUS as they tend to come in contact with vital organs in chest & abdomen INCISED WOUNDS

CHARACTERS: 

Broader than the edge of weapon causing it – retraction of divided tissue Spindle shaped & gaping ( zigzag, Cresentric also present) Middle of wound – depth more & wider gaping Gaping is greater in deep wounds when muscle fibres are cut transversely or obliquely Gaping is more if cut at right angles to the ‘lines of Langer’ & less if parallel to this CHARACTERS

CHARACTERS: 

Edges – smooth, even, clean cut, well defined, usually everted Inverted in scrotum – thin muscle fibre closely united to skin – lacerated looking incised wound CHARACTERS

CHARACTERS: 

Irregular edges – axilla , anterior abdominal wall (skin is loose) or cutting edge of weapom is blunt (skin ‘ ll be puckered) Length is greater than width & depth Commencement of wound is deeper & gradually become shallower & ending in tailing scratch Length has no relation with length of cutting edge of weapon Bleeding is more in clean cut If sharp weapon edge struck obliquely – bevelling of one edge Sharp edge struck horizontally – wound with a flap CHARACTERS

AGE OF INCISED WOUND: 

AGE OF INCISED WOUND Aseptic incised wound in apposition ‘ ll covered with lymph – 36 hrs Join edges – 3 dys Wound heal by first intention forms red, tender, linear scar– 7 dys If it is in face heals rapidly – 3-5 dys

AGE OF INCISED WOUND: 

Not aseptic & gaping owing to loss of tissue – heals by formation of granulation tissue Edges bound together by blood & lymph – 12 hrs (margins ‘ ll be red & slightly swollen with leucocytic infiltration) Small wound show scab formation – 24 hrs Pus ‘ ll appear – 36-48 hrs (if become septic) ‘ ll not heal for wks, if sloughing of surrounding tissue has occurred from suppuration AGE OF INCISED WOUND

AGE OF INCISED WOUND: 

Vascular endothelium proliferates & vascular buds are given off minute vessels at periphery in 24 hrs Complete network of new capillaries – 36 hrs Spindle shaped cells runs at right angles to vessels in deeper part – 48 hrs Definite fibrils run parallel with long fibroblast – 5 dys Cellular structure & vessels obliterated & replaced by dense fibrous scar – 3-4 wks Tough white glistening scar – 6 mnths AGE OF INCISED WOUND

SUICIDAL: 

SUICIDAL Tentative or hesitation cut weapon move in a saw like fashion Seen on throat, abdomen, wrist Multiple, parallel, & superficial Cause of death often – air embolism

HOMICIDAL: 

HOMICIDAL Throat By heavy cutting weapons like chopper, sword, butcher’s knife or even razor Manner of infliction – slashing or sawing Often single & deep Deeper structures may be involved

MEDICO LEGAL SIGNIFICANCE: 

MEDICO LEGAL SIGNIFICANCE Points to the use of a cutting weapon Length, width, or depth ‘ ll not correspond to that of weapon Tailing gives direction Site may suggest the possible motive, intent, or even the mental status of assailant

PUNCTURED WOUNDS: 

PUNCTURED WOUNDS Piercing wounds produced by sharp pointed objects Definite relation to weapon used Depth is more than length or width & equal to or less than length of blade of the weapon

TYPES: 

TYPES Penetrating wound Perforating wound Incised stab wound Lacerated stab wound Concealed puncture wounds

PENETRATING WOUND: 

PENETRATING WOUND Terminates in tissues, organ, or cavity

PERFORATING WOUND: 

PERFORATING WOUND Transfix organ, limb or trunk Have two separate surface wounds – entry & exit External bleeding may slight, internal bleeding can be very profuse Wound of entry usually larger than wound of exit –weapon usually taper towards tip Edge of entry mostly inverted, exit – everted Direction can be deduced by joining entry & exit

INCISED STAB WOUND: 

INCISED STAB WOUND Starts as incised wound, Ends as a stab wound when there is a sudden thrust at the termination of incised wound Or it may begin as stab wound & become incised as the knife is pulled out with a little bit of dragging

LACERATED STAB WOUND: 

LACERATED STAB WOUND Entry wound is slit like or oval shaped or round with irregular bruised margin, according to the weapon used

CONCEALED PUNCTURE WOUNDS: 

CONCEALED PUNCTURE WOUNDS In some stab homicides To conceal its presence Stabbing may be through a natural orifice (ear, nostril, vagina, rectum) Stabbing may be in unusual location ( axilla , nape of neck)

MEDICOLEGAL SIGNIFICANCE: 

MEDICOLEGAL SIGNIFICANCE External appearance of stab wound may give a clue regarding kind of weapon If both ends are sharp cut – double edged or tip of single edged, single edged tilted on withdrawal or weapon possesses a curved beak – spindle shaped wound Bruising around stab may indicates weapon had been inserted up to the hilt Round or pointed weapon like spear produce circular stab wound Pointed weapon that is square shaped in cross section ‘ ll produce cross shaped stab wound

MEDICOLEGAL SIGNIFICANCE: 

Stabbing with frock produce clusters of 3, 4 puntcure wounds Small slit like stabs produced by stabbing with screw driver May not produce significant external bleeding, but pruduce extensive internal bleeding If stab enters the skin obliquely edge of wound on the side from which weapon has entered become “ bevelled ” & other edge over hanging – wound inflicted direction can be ascertained Exit wound is smaller than entry wound MEDICOLEGAL SIGNIFICANCE

MEDICOLEGAL SIGNIFICANCE: 

Depth of wound give minimum length of weapon used In yielding areas like abdomen & ends up in a cavity or collapsible organ like lung - depth can sometimes be more than length of the blade Length of entry wound may be equal to breadth of stabbing weapon Usually it may lesser by 2-3 mm if skin is elastic Width of entry wound is usually greeter than thickness of weapon due to gaping MEDICOLEGAL SIGNIFICANCE

MEDICOLEGAL SIGNIFICANCE: 

Stab wounds may be suicidal, homicidal or accidental Suicidal stabs are usually single, over left side of chest Concealed puncture wounds may seen in ear, nostril, vagina, rectum, axilla , nape of neck MEDICOLEGAL SIGNIFICANCE

DEFENSE WOUND: 

DEFENSE WOUND Found on upper limb of the victims or may on legs Produced during warding off an attack or grabbing weapon Superficial injuries on other parts of body may indicate struggle It may be fabricated to substantiate a charge of homicidal assault – on accessible areas, may not be serious

HOMICIDE/SUICIDE/ACCIDENT: 

HOMICIDE/SUICIDE/ACCIDENT Suicidal stabs ‘ ll be in accessible areas All stab wounds have to be considered as homicidal, unless otherwise proved Accidental punctured wounds can occur by falling over sharp pointed fixed objects – other injuries like abrasion, contusion ‘ ll also present to indicate a fall Stab wounds occurring during a scuffle between persons holding weapons may also happens – stab ‘ ll not be deep, may have tailing ends

REFERENCES: 

REFERENCES Amrit K. Patnaik , K. Mathiharan . Modi’s Medical Jurisprudence & Toxicology. 23 rd ed 2010 B. Umadethan . Forensic Medicine. 1 st ed. 2011 V. V. Pillay . Textbook of Forensic Medicine & Toxicology. 16 th ed.2011

THANK YOU: 

THANK YOU