This document discusses different types of injuries, including mechanical injuries caused by physical violence or trauma. Mechanical injuries are classified as blunt force trauma, sharp force trauma, or firearm injuries. Blunt force trauma includes abrasions, contusions, and lacerations. Abrasions are further classified as scratches, grazes, pressure abrasions, patterned abrasions, and atypical abrasions like nail marks. The age of an abrasion can be estimated based on changes like scabbing that occur over 12-24 hours and 2-3 days as it heals.

1. INJURIES

2.  Legally- any harm whatever in nature illegally caused to the body ,mind
,reputation or property . (IPC-44)
 Clinically (Medico-legally )- Trauma or injury is defined as breach or dissolution of
the natural continuity of any of the tissue of a living body by actual physical
violence .
 Classification –Classified in three ways : Medical , Legal and Medico –legal.
 1.Medical :-Depending upon the causative factor it is of following types :-
a.Mechanical injury
b.Thermal
c.Chemical
d.Physical
e.Explosives

3.  Legal :-
a.Simple
b.Grevious
▪︎Medico –legal :-
a.Suicidal
b.Homicidal
c.Accidental
d.Fabricated
e.Defence

4. MECHANICAL INJURIES
▪︎ All injuries sustained due to physical violence to the body constitute mechanical trauma or
mechanical injury.
Usually there are two mechanisms encountered and they are:
Impact of a moving object – Here the trauma is due to the impact of a moving object on a
relatively non-mobile victim, e.g., a cricket ball hit by a batsman strikes a spectator watching the
game.
Impact of a virtually Non-moving object on actively moving Victim – Here the mechanical
trauma
is due to the impact of moving victim who directly hits against a non-moving object, e.g., a
scooter driver collides with an electric pole..

5. CLASSIFICATION
 Mechanical trauma is further sub-classified into :-
a. blunt force trauma
b.sharp force trauma and
c. Firearm injuries
A. BLUNT FORCE TRAUMA :-
It is injury produced by weapons or objects with blunt edges
or surfaces. Basically they are:
• Abrasion
• Contusion
• Laceration.

6. B.SHARP FORCE TRAUMA :-
It is injuries produced by weapons or objects with sharp cutting edge or edges.
Basically they are:
• Incised wound
• Stab wound
• Chop wound.
C.FIREARMS INJURIES :-
These are injuries produced by firearms. They are further classified into:
• Injuries by rifled firearms (gunshot injuries)
• Injuries produced by smooth bored firearms (shotgun injuries)

7. INJURIES BY BLUNT FORCE
ABRASION :-
It is defined as superficial injury, inducing displacement of only epidermis in the skin by friction.
Various causes leading to development of an Abrasion are:
Fall on rough surface
Blow with blunt weapon
Dragged by the vehicle
Hurt by fingernails, thorns, teeth bite etc.
 Some pressure and movement by agent on the surface of the skin is essential. The exposed raw surface is
covered by exudation of lymph and blood which produces a protective known as a crust or scab. They vary
in size, depending on the extent of the body surface exposed to the abrading force.
 Abrasions are simple injury – produces minimum bleeding, heals rapidly within seven days and leaves no
permanent scarring on healing.

8. TYPES OF ABRAISONS :-
Depending upon the mechanism of the pressure and nature and movement of the
weapon/agent involved against the skin surface, abrasions may be classified as
follows.
1.SCRATCHES OR LINEAR ABRASIONS :-
These are produced by horizontal or tangential friction by the pointed end of some
object like thorn, nail, needle or tip of any weapon.

9. 2.GRAZES (SLIDING/TANGENTIAL/BRUSH ABRASIONS):-
These are caused due to horizontal or tangential friction between the broader area
of the skin and the object/weapon or hard rough surface of the ground.

10. 3.PRESSURE ABRASIONS (CRUSHING ABRASIONS/IMPRINT ABRASIONS):-
When the impact is vertical to the skin surface, the epidermis gets crushed and
pressure type of abrasions result and the imprint of the impacting object may be
produced. These may be seen in manual strangulation (abrasions produced by
fingernails) and in hanging.

11. PATTERNED ABRASIONS:-
Patterned abrasions occur when the force is applied at or around right angle to the
surface of the skin.If a weapon with patterned surface strikes the body or body falls
upon a patterned rough hard surface, the abrasions will usually follow the pattern
of the object.

12. 5.ATYPICAL ABRASIONS :-
 Nail marks and teeth bites may conveniently be included in this category of
abrasions though they may produce lacerations too, depending upon the force
applied. Nail marks are especially important in cases of child abuse, sexual
offences and manual strangulation. They may appear as linear scratches or s
straight or curved marks depending upon the circumstances.

13.  AGE (FATE) OF AN ABRASION

 Abrasions usually heal rapidly without any scar formation, unless

 they are deep enough to involve the dermis, which prevents

 regrowth of hair follicles and sebaceous glands. A rough idea

 about their age may be gathered from the following changes:

 Fresh: The area will appear reddish due to oozing out

 of serum and little blood. The dermis will be

 congested and painful.

 12–24 hours: The exudation dries up to form a reddish scab,

 comprising dried blood, lymph and injured epi-

 thelial cells.

 2–3 days: The scab is reddish-brown, less tender and adher-