Abrasion
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/rope.
Types of abrasions
1.Scratch abrasion
- Synonym: linear abrasion
- Sharp or pointed object not sharp enough to cause incised wound, but pointed enough to scratch
- E.g. thorn, fingernails(Crescent shaped abrasion ), tip of knife
- Clean area at the start of the wound and tags at the end
- Helps in determining the direction of force
2.Graze abrasion
- Synonyms: grinding or sliding abrasions, brush burns
- Most common type – Commonly seen in road traffic accidents
- Mimics burn
- Occurs when the skin is rubbed (friction) against some rough surface
- Uneven, longitudinal parallel lines of abrasion are seen
- Epithelium heaped up at the end of these lines which indicates the direction of force
3. Pressure abrasion
- Synonym: crushing abrasion
- Sustained pressure of a rough object at 90° – crushing of the superficial layers of the skin
- No force on impact, but sustained pressure after the object comes in contact with body surface
- E.g. Ligature mark in hanging and strangulation
4. Impact abrasions
- Synonym: Contact abrasion or Imprint abrasion
- There is a moment of forceful impact, after that no contact of the object with body
- E.g: radiator grill mark, tyre tread marks seen in RTA
Patterned abrasion
- lmpact abrasion or pressure abrasion, which show pattern of the object (causing injury) are called patterned abrasion.
- Examples are pattern of cycle chain, pattern of whip, pattern of teeth ond nails,Pattern of tyre, pattern of string in hanging and strangulation (ligature mark), pattern of head light/bumper/radiator in vehicles occident, and pottern of porallel lines in (railwoy line pattern) blow with a stick.
Artifacts in Abrasion
- By Ants.
- By Insects.
- By Animals.
- By Marine animals.
Medico legal importance
- Gives a clue about the direction of trauma
|
- Helps to identify certain features of the causative agent
Imprint of the muzzle of a shotgun (Abrasion ring) |
Imprint of the hilt guard of a knife |
- Helps in finding the time of injury
- The pattern of abrasions provide evidence of the nature and the mechanism of trauma.
eg. grazed abrasions in different directions all over exposed areas of the body indicate that a body has been thrown on a rough surface in different directions.
- An abrasion can be categorized for medico legal purposes .
- Helps in reconstructing the incident eg. finger nail abrasions in strangulation helps in finding the relative position of both victim and the assailant
- Indicates the type of crime eg. strangulation, sexual offence etc
Antemortem Abrasions
- Reddish brown colour.
- Margins are blurred due to vital reactions.
- Antemortem Abrasions can be confused with ant bite marks.
- Yellowish in colour.
- Translucent area.
- Margins are sharply defined.
- Absence of vital reactions
Exam Important
Types of abrasions
1.Scratch abrasion
- Synonym: linear abrasion
- E.g. thorn, fingernails(Crescent shaped abrasion ), tip of knife
2.Graze abrasion
- Synonyms: grinding or sliding abrasions, brush burns
- Most common type – Commonly seen in road traffic accidents
- Mimics burn
3. Pressure abrasion
- Synonym: crushing abrasion
- E.g. Ligature mark in hanging and strangulation
4. Impact abrasions
- Synonym: Contact abrasion or Imprint abrasion
Patterned abrasion
- lmpact abrasion or pressure abrasion, which show pattern of the object (causing injury) are called patterned abrasion.
- Examples are pattern of cycle chain, pattern of whip, pattern of teeth ond nails,Pattern of tyre, pattern of string in hanging and strangulation (ligature mark), pattern of head light/bumper/radiator in vehicles occident, and pottern of porallel lines in (railwoy line pattern) blow with a stick.
Antemortem Abrasions
- Reddish brown colour.
- Margins are blurred due to vital reactions.
- Antemortem Abrasions can be confused with ant bite marks