Contusions/Bruises and their Forensic Significance

Contusions are one of the most common types of injuries occurring in active children. A contusion, or bruise, is caused by a direct blow to the body that can cause damage to the surface of the skin and to deeper tissues as well depending on the severity of the blow. This type of injuries occurs when blood vessels in the skin or internal organ are ruptured. These injuries are type of Mechanical injuries and fall under blunt force injury. They are caused by blunt force, such as, fist, stone, stick, whip, boot, etc. Usually there is no loss of continuity of skin but they may be associated with abrasions or lacerations. A fresh bruise is usually tender and slightly raised above the surface of the skin. The size varies from small pin head to large collections of blood in the tissues. There are two types of bruises – Patterned bruise and Artifical Bruises.

Patterned Bruising

A bruise is usually round but it may indicate the nature of the weapon used. A blow from a hammer or the closed fist usually produce a round bruise. Bruise made by the end of a thick stick may be round, but if any length of the stick hits the body they are enlarged and irregular. A blow with a rod, a stick or a whip produces two parallel linear hemorrhages. The intervening skin is unchanged. In bruise produced by a long rigid weapon, e.g. stick, the edges of the bruise may be irregular and the width may be greater due to the infiltration of blood in the surrounding tissues along the edges of the bruise. Bruises caused by blows from whips are elongated, curve over prominences, and may partially encircle a limb or the body and are seen as two parallel lines. Bruises from straps, belts or chains leave a definite imprint. Patterned bruising is also seen in motorcar accidents.

Artificial Bruises

Some irritant substances, e.g. juice of marking nut or Calotropis, when applied to skin produce injuries, which stimulate bruises. They are seen on exposed accessible parts of the body, colour is dark brown, shape is irregular, margins are well defined and regular and are covered with small vesicles, ecchymosis is absent, contain acrid serum, itching is present, and vesicles may be found on finger tips and on other parts of the body due to scratching.

Difference Between Antemortem and Postmortem Bruises.

Antemortem Brusises	Postmortem Bruises
Colour changes present	Absent
Superficial and deep	Usually superfical only
Ecchymosis is more	Very less
Signs of inflammation and other vital reaction seen	Absent
On microscopic examination such changes and other changes can be demonstrated	No infiltration of leucocytes

What Affects the Appearance of a Bruise?

Bruising is one of the most common types of physical injury observed in victims of violence, assault, and abuse. There are several factors that affect a bruise’s appearance, such as:

• Tissue type – Loose connective tissue type sites, such as the eye, face, and genitalia show more bruising.

• Fat content at the location of the injury – The more fat, compared to muscle, can contribute to an increase in bleeding.

• Age of the victim – Infants bruise easily because of their loose and delicate skin. The elderly bruise easily because they have decreased elasticity of the skin and blood vessels.

• The depth of the injury – Superficial bruises may present immediately, while deep bruises may take hours or even several days to appear.

• Characteristics of the inflicting object, including its surface and force of impact against the body – This affects the bruise’s size, shape and pattern of appearance.

Difference Between Postmortem staining and Bruises.

Postmortem staining is a bluish or reddish-purple discoloration due to capillo-venous distension with blood, at the undersurface of the skin of the dependant parts of the body, due to settling of blood in those areas due to pull of the gravity, when circulation to keep the blood in motion ceases. And these can be confuse with bruises. Following are some traits that differentiate PM staining and bruises.

Traits	Postmortem Staining	Bruises
Causes	Due to dilatation of blood vessels in dermis	Due to rupture of blood vessels
Site	Seen on dependent parts of body	Any where on the body
Appearance	No elevation of the involved area	Swollen due to extravasated blood and oedema
Epidermis	Not abraded	May be abraded
Margins	Clearly Defined	Merge with the surrounding area
Colour	Uniform Bluish purple in colour	Colour Changes with the age of the injury
On Incision	Blood is seen in blood vessels, which can be easily washed away	Extravasated and clotted blood is seen in surrounding tissues, it cannot be washed away easily
Effect of pressure	Absent	Little lighter over the area of pressure

Characteristics and Forensic Significance of Bruise

The colour change is very variable, starts at the periphery and extends inwards to the center. At first its colour is red, after few hours to 3 days it converted in to blue on 4th days is changes into bluish-black. When bruising is extensive and deeply situated the colour takes longer time to appear externally.

• Bruises may not always show at the original impact site due to gravity shifting
• Size of the bruise may not necessarily commensurate with the severity of trauma
• Deep bruises may take 1-2 days to become visible externally, therefore re-examination after 1-2 days is recommended
• Deep bruises may never show up externally (e.g. in vehicular accidents). Deep incisions at autopsy are necessary to demonstrate them.

Forensic Significance

• Nature of trauma i.e. blunt
• Indicator of ante mortem nature
• Site of trauma (Gravity shifting must be kept in mind)
• Degree of violence
• Identity of weapon
• Time or age of injury
• Purpose of injury
• Whether homicidal, suicidal or accidental