The term ‘injury’, under Section 44 of IPC, denotes any harm illegally caused to any person, on body, mind, reputation, or property. It will include any tortuous act also. Injuries can be severe life-threatening or they may be mild. The type of injury formed depends on the manner and how they are caused.
The thickness of the skin has forensic relevance in the amount of injury that is required to penetrate the skin and cause bleeding from the underlying tissues. The human body is exposed to mechanical forces quite often and the body usually absorbs such force either by resilience and elasticity of the soft tissue or by the rigid strength of the skeletal framework. When the intensity of the force applied on the skin is more than the threshold limit a wound occurs.
Injury is a broader term and it is often used synonymously with trauma and wound. The injury will include any lesion, external or internal caused by violence, with or without breach of continuity of the skin.
Classification Depending on Causative Factor
A. Caused by Blunt Force
It is a type of mechanical injury caused due to the application of a mechanical force which can be sliding or compressive that results in the loss of the superficial layer of the skin or mucous membrane will no or minimal bleeding.
It is caused by a blunt force causing the collection of blood due to rupture of blood vessels. The mechanical force of blunt nature crushes and tears the subcutaneous tissue without breaking the overlying skin.
It is defined as a form of injury caused by hard and blunt force impact characterized by splitting or tearing of the tissues.
B) Caused By Sharp Force
This type of wound is produced by light and sharp cutting weapons or force when applied over a very narrow area corresponding to the cutting edge of the weapon. This wound is characterized by an orderly solution of the skin and tissues.
They are otherwise known as stab wounds and are piercing types of wounds that will penetrate or perforate the skin due to the application of mechanical force along the long axis of a narrow or pointed object.
C) Caused by Firearm
1. By Rifled Firearm
2. By Smoothbore Firearm
3. by Country Made Firearm
The wounds caused by each type of firearm will be different depending on the range of firing. Also, each type of firearm uses a different type of bullets or cartridges, primer composition, type of propellant, site of the body that got hit, striking velocity all influence the pattern and type of wound.
D) Caused by Chemical Agents
Corrosions are caused due to strong acid or strong alkali and irritation can happen because of weak acids and alkali, animal or vegetable extract, and so on.
E) Thermal Injuries
1. Due to heat
General effects like heat stroke, heat cramps, and heat exhaustion and local effects like burns and scalds are examples of injuries due to heat.
2. Due to cold
Exposure to cold can cause frostbite, trench foot, pernio, and hypothermia. Hypothermia is a state where an individual’s core body temperature is below 35℃. Pernio is also known as chilblains which is a vasculitic disorder where the patient develops raised erythematous lesions on the lower parts of the legs and feet.
Trench foot otherwise known as immersion foot occurs when the foot or hand is exposed to a temperature as low as 5-6℃ if the limbs are wet. Frostbite happens due to exposure to a temperature below 0℃.
If a person is struck with lightning, then the injuries can happen due to the electric current, heat effect, successive expansion, and regression of heated air. Lightning can strike a victim by direct stroke, side stroke while using electrical appliances during lightning, or due to ground current.
A person can get electrocuted as a cause of contact injury, flash burn, or spark burns.
4. Blast Injuries
Classification Depending Upon Gravity
Classification Depending Upon Time of Infliction
Antemortem injuries are those inflicted before death and will show signs of healing. Postmortem injuries are caused after death and show no signs of healing, perimortem injuries occur at or around the time of death, these wounds might appear fresh but will not show signs of healing.
Classification Depending Upon Manner of Infliction
- Defence Wounds
- Fabricated/Fictitious Injuries
Classification of injuries is important because each type of injury reveals a lot about its cause. Classification helps to identify the features in detail and co-relate it to the cause of the injury, offending weapon, age of the injury, time of infliction, and so on.
In the forensic investigation, it is important to determine whether a wound was suicidal, homicidal, or accidental and also whether it was inflicted before or after death. Analyzing an injury also helps in the reconstruction of a possible sequence of events that occurred.