A contusion, also known as a bruise is the extravasation or collection of blood due to the rupture of blood vessels caused by the application of mechanical force of blunt nature without loss of continuity of tissues. It is caused by a blunt force impact causing crushing or tearing of subcutaneous tissue or dermis without breaking the overlying skin. As the blood vessels rupture, the blood gets collected underneath the tissue. This causes swelling and pain.
Contusions may be present in the internal organs like brain, lungs, etc. Contusions over the brainstem are often fatal. Contusions on the heart can disrupt the normal rhythm and can cause cardiac failure. Contusions when present on organs can rupture the cellular covering with resulting bleeding. Postmortem and antemortem contusions can be distinguished as swellings, extravasation of blood, signs of inflammation, and hemorrhage are present only in antemortem contusions.
If contusions are inflicted on vital parts like the heart, or neck then it may cause death. Multiple contusions can cause death due to shock, or hemorrhage. The size of the bruise may not correspond with the size of the offending weapon nor do they indicate the direction in which the force was applied. When a large blood vessel is injured, a tumor-like mass called hematoma is formed. Petechial bruises are finely mottled or stippled. If the petechiae become larger and confluent, they are called ecchymoses. The greater the force of violence used, the more extensive the bruise will be.
Types of Contusions
1. Intradermal Bruise
This type of bruise will be present in the sub-epidermal layer of the skin. They are superficially present and occur at the point of application of the force. The margins are distinct. Motor tire marks, impact from a whip, and impact from rubber soles of shoes are examples of this type of contusion.
2. Subcutaneous Bruise
This type of bruising is the most common. They are located in the subcutaneous tissue often in the fat layer above the deep fascia and so are visible through the skin. They are also known as superficial bruises. If the depth is more, then it is known as a deep contusion. The margins of these bruises appear blurred especially at the edges.
3. Patterned Bruise
Patterned contusions will have the imprint or design of the offending weapon or the object. This helps in identifying the nature of the offending object or weapon.
4. Tram Line Contusion
These are caused by the blow of a rod, stick, belt, or any such object over the skin which compresses the skin beneath the area of contact. The blood in that area gets displaced sideways causing tram-track-like hemorrhages on the sides of the skin. This type of bruise is also known as tram-track contusions or rail-road contusions.
5. Six-Penny Bruises
They are discoid-shaped bruises that result from fingertip pressure. They are commonly found in cases of manual strangulation over the neck and in cases of child abuse.
6. Shifting Bruise
These bruises appear at a different site and not on the actual site of application of the mechanical force. This feature is associated with deep-seated contusion and so takes a lot of time to appear at the skin surface. The movement from deep tissue towards the surface is governed by factors like fascial planes, the anatomical structure of the location, the gravitational force acting. These are also known as a migratory contusion, ectopic contusion, or percolated contusion, come-out bruise.
7. Artificial Bruises
These can be produced due to the application of some irritant substances like Marking Nut, Calotropis, Plumbago zeylanica, Plumbago rosea. This is done to make false allegations against somebody.
Age of Contusions
|Fresh||Reddish in color|
|Within a few hours.||Bluish in color|
|2nd day||Bluish-purple coloration|
|Till the fourth day||Bluish-black|
|4-5 days||Brownish due to the presence of hemosiderin|
|5-7 days||Greenish due to the presence of haematoidin|
|7-10 days||Yellow due to bilirubin|
|Within 1 and a half week||Yellow color slowly fades in tint|
|About 2 weeks||Normal color is restored.|
Factors Affecting Bruises
a) Colour of Skin
Bruising appears more prominently in people with fair complexion than in people with a darker complexion.
b) Age of the Individual
Children’s bruises easily as they have more soft tissue composition and less volume of protecting tissues. Old persons too bruise easily owing to loss of flesh and accompanying cardiovascular changes.
c) Sex of Individual
As women have more subcutaneous fat and delicate tissue, bruising is seen more in women than in men.
d) Amount of Force
If the tissue involved is loose and lax such as the face, scrotum, genitalia, eyelids, etc. a moderate blow may result in a relatively large bruise. If the tissues are strongly supported containing firm fibrous tissues and covered by thick dermis such as back, scalp, palms, and soles, etc. a blow of moderate violence may produce a comparatively small bruise.
e) Peculiarities of the Victim
Chronic alcoholics bruise easily because of cutaneous vasodilation. Boxers and athletes show comparatively less bruising due to good muscle tone, which may prevent easy rupture of blood vessels. The presence of some diseases like scurvy, vitamin K and prothrombin deficiency, hemophilia, leukemia, atherosclerosis, etc. may produce exaggerated bruising.
f) Vascularity of the Area
The size and density of the vascular network vary from area to area and that is why bruising over the areas like face, genitalia, scrotum, etc., having rich vascularity, will be more as compared to other areas.
g) Resiliency of Area
Resilient areas such as the abdominal wall, buttocks, etc. bruise less with a given impact than the region having a bone immediately underneath and with the least amount of subcutaneous tissue, like head, shins, and areas against iliac crests.
Contusions have medicolegal importance because bruises like patterned bruising can indicate the offending weapon. The age of injury, character, and manner of the injury can be determined. The application of the degree of violence can also be estimated.
The bruises may be confused with postmortem lividity, congestion, artificial bruise, or purpura and hence it is important to know about the features of such injuries to avoid false findings.