Forensic

• Simple wound


  Heals in less than 10 days, leaves no permanent infirmity
• Dangerous wound


  Heals in more than 40 days and/or leaving an infirmity
• Fatal or mortal wound


  Cause death immediately or later
• Classification of wounds


  • Legal classification
  • Medico legal classification
• Legal classification


  • Incised wound
  • Stab wound
• Medico legal classification


  • Blunt
  • Sharp
  • Firearm
  • Physical agents
  • Chemical agents
• Mechanical wounds


  Any breach in the natural continuity of a tissue or organ caused by application of mechanical force to the body
• Mechanical force can be

  • Sharp force
  • Blunt force
• Mechanical wounds


  • Cut wounds
  • Stab wounds
• Abrasions, Bruises, Lacerations

  • Abrasions: by pointed OR rough blunt instrument
  • Contusions: by smooth blunt instrument
  • Lacerations and contused wounds: by heavy blunt instrument
• Abrasions


  Destruction of the superficial layers of the skin following contact with a pointed OR rough blunt object
• Types of abrasions


  • Tangential force (Sliding abrasions)
  • Perpendicular force (Patterned abrasions)
• Sliding abrasions


  • Scratches
  • Grazes (brush abrasions)
• Patterned abrasions


  Abrasions that retained the pattern of the impacting object
• Examples of patterned abrasions

  • Tyre marks
  • Steering wheel
  • Hanging
  • Strangulation
  • Human bites
  • Animal bites
• Medico legal importance of abrasions

  • Gives an idea about the instrument used
  • Gives an idea about the direction of the force
  • Differentiate cut from contused wounds, bruises from hypostasis, inlet and exit of bullet
  • Gives idea about time passed since injury (healing stages)
  • May indicate the type of crime
• Examples of medico legal importance of abrasions

  • Semilunar abrasions around mouth suggest smothering
  • Semilunar abrasions on the neck suggest throttling
  • Rope marks on neck suggest hanging or strangulation
  • Finger nail abrasions on the body of both the victim & the assailant indicate resistance or struggle
• Bruises (Contusions)


  Extravasations of blood in the tissues following rupture of blood vessels as a result of application of force using smooth blunt or rough object
• Characteristics of bruises


  • Can be superficial or in deep organs
  • Ruptured vessels are mainly venules
  • Skin over it intact and may associated with abrasions (Abraded Contusions)
  • Takes the shape of causal instrument
  • Blood may gravitate and appear in lower site

  
• Color changes of bruises over time

  • In first 24 hrs: bright red (oxygenated Hb)
  • In 2 days: dark red to blue (deoxygenated Hb)
  • In 2-4 days: purple brown (Hemosiderin)
  • In 4-7 days: brown – green (Biliverdin)
  • In 8-14 days: green - yellow (Bilirubin)
  • In 14- 30 days: color disappears
• Medico legal importance of bruises

  • May be the only evidence of crime or violence
  • May be the only evidence of signs of resistance
  • The date of the crime can be estimated from its age
  • Give an idea about the instrument used
  • Differentiate between incised & contused wound
  • Should be differentiated from hypostasis
  • May be the cause of death
• Consequences of bruises


  • Fat embolism
  • Injury to internal organs
  • Renal failure (crush injury)
  • Liability to sepsis & death from septicemia
  • Neurogenic shock (reflex vagal inhibition)
• Lacerated wound


  Tear OR split of the skin, mucous membrane, muscle and may internal organs, Caused by application of blunt force

  
• Characteristics of lacerated wounds

  • Edges: Irregular, Abraded, uneven, Angle: Multiple
  • Length & Depth: variable, Gapping: present
  • Base: Irregular show tissue bridging
  • Abrasions & bruises at the edges
  • Crushed hair at the edges (microscope)
  • Little bleeding (crushed blood vessels)
  • More liable to sepsis (dirty instrument)
  • Take longer time to heal, usually by 2nd intention & leave thick permanent scar

  
• Subtypes of lacerated wounds

  • Split wound
  • Contused wound
• Incised (Cut) Wounds


  Clean cut wound caused by drawing the edge of sharp instrument along the surface of the skin
• Characteristics of incised wounds

  • Angle: Acute
  • Edge: Sharp, regular, clean, well defined
  • Length: Greater than depth & width
  • Width: greater than the thickness of the edge of the blade
  • Base: Cleanly cut, No bridging
  • Direction: Deep, wide at its origin (head) & superficial, narrow at its end (tailing)
  • Profuse external bleeding
  • No abrasions or contusions at the edges
  • Less liability to sepsis (clean cut wound)
  • Healing is rapid leaving a thin linear scar

  
• Contused wound may simulate cut wound can be differentiated by crushed or torn hair, may be surrounded by abrasions and contusions, irregular & abraded edges with variable depth
• Contused wound


  May simulate cut wound, can be differentiated by: Crushed or torn hair, May surrounded by abrasions and contusions, Irregular & abraded edges with variable depth
• Subtypes of Lacerated wound

  • Split wound
  • Contused wound
  • Incised (Cut) Wounds
• Incised (Cut) Wounds


  A clean cut wound caused by drawing the edge of a sharp instrument along the surface of the skin
• Characteristics of cut wounds

  • Acute angle, Sharp, regular, clean, well defined edges, Length greater than depth & width, Width greater than thickness of blade edge, Cleanly cut base, Deep at origin, superficial at end
• Cut wounds


  • Profuse external bleeding, No abrasions or contusions, Less liability to sepsis, Rapid healing leaving thin linear scar

  
• Chop (SLASH) wound


  Caused by blow with sharp cutting edge of heavy instrument, Has clean-cut edge but abraded and bruised margins due to friction against the sides of the wide blade on cutting
• Differentiation between cut and contused wounds


  • Edges (Regular vs Irregular)
  • Tissue bridging (Absent vs Present)
  • Surrounding abrasions (Absent vs Present)
  • Hair at margin (Sharply cut vs Crushed)
  • External Bleeding (Profuse vs Slight)
  • Tendency to gap (More vs Less)
  • Liability to sepsis (Less vs More)
  • Healing & scar (1st intention, thin vs 2nd intention, thick)

  
• Stab Wounds


  Penetrating injuries caused by forcing sharp pointed instruments into the body in stabbing manner, most commonly by knife, dagger, sword
• Characteristics of Stab Wounds

  • Edges: Regular, cleanly cut

  Angles: Single bladed (one sharp angle), Double bladed (two sharp angles)

  Base: Deep, may show broken tip of weapon

  Length: Less than depth, More deeper than longer

  Bleeding: Slight external, massive internal

  Sepsis: More due to blood accumulation in wound

  
• Multiple angles (cruciate appearance) indicate the weapon was twisted or rotated during withdrawal
• Stab wound length


  Wound length is ≤ blade width due to recoil of skin on withdrawal or tapered blade not fully inserted
• Stab wound depth


  Is ≤ length of instrument if not fully inserted, Is ≥ length of instrument if fully inserted and body surface compressed