Medicolegal Investigation of Blunt Force Injuries

Medicolegal Investigation of Blunt Force Injuries Forensic Yard (8)

According to section 44 of IPC, the term injury denotes any harm illegally caused to any person, on body, mind, reputation, or property. It also includes tortuous acts. The characters of any injury caused by some mechanical force depend upon the nature and shape of the weapon, the nature of the tissue involved, the amount of energy in the weapon or instrument when it strikes the body, whether inflicted on a moving or a fixed body, the velocity of the weapon, area of action.

Injuries caused by a blunt force are physical trauma and are non-penetrating. It occurs due to incidents such as road traffic collisions, direct blows, assaults, injuries during sports. Most of the injuries due to a blunt force are not deep and do not create an open wound. Rarely, injuries due to a blunt force cause death and so most of the time these wounds will show signs of healing. Thus by looking at the age of the wound time of infliction can be estimated.   

The blunt impact can cause different types of injuries like laceration, abrasion, or contusion. The severity of the blunt force is related to the mechanism of the injury as well as the underlying comorbidities of the person. Blunt impact injuries are commonly seen in forensic autopsy practice, and appropriate interpretation of wounds is essential for accurate medico-legal testimony.

Types of Blunt Force Injuries

1. Abrasion

It is a type of mechanical injury that is characterized by the loss of superficial skin or mucous membrane due to the application of mechanical force. Pure abrasions do not ordinarily bleed but because of the corrugated nature of dermal papillae. Quite often the dermis layer also gets injured, and thus bleeding might occur. This bleeding is rarely serious as only small blood vessels are involved. Abrasions can be produced due to sliding force or compression force.

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There are different types of abrasions namely scratches or linear abrasion, graze abrasion, pressure abrasion, patterned abrasions. The medicolegal importance lies in the fact that they are produced at the point of impact of the blunt force, they may exhibit a pattern thereby providing information regarding the nature of force, their sites and distribution over the body may yield some clue towards the nature of the crime.

Scratches over the neck, face or inguinal region of a female may be produced by the fingernails of the assailant during the sexual assault. The presence of some foreign material like mud, dust, sand, etc in and around the abraded area will suggest the nature of the surface or agent responsible for its causation. These are also helpful in determining the approximate period of infliction of the injury.

Age of Abrasion

DurationFeatures
FreshReddish due to oozing out of serum and little blood
12-24 hoursDries up to form a reddish scab
2-3 daysThe scab is reddish-brown
4-5 daysThe scab turns dark brown
5-7 daysThe scab appears to be brownish-black and starts falling from the margins.
7-10 daysThe scab shrinks and falls off, leaving some unpigmented area underneath.

2. Contusions/Bruises

These are also known as bruises. It is a 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 tissue. This collection of blood is accompanied by swelling and pain. A pure bruise lies beneath the intact epidermis. The black eye following a fistfight, the scalp hemorrhage from a fall, and the bluish-purple appearance after an upper arm is squeezed too tightly are few examples of contusions.  

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A bruise is evidence of the application of blunt force. It is unusual for a suicide case to have bruises. But to support a false charge, bruises are sometimes simulated by the application of some irritants such as the juice of bhilawa(marking nut), or the roots of Chitra(plumbago zeylanica) or lal Chitra (plumbago rosea).

If patterned bruising is present, then it gives a clue about the nature of the agent used in the assault. Healing will indicate the age of the bruise. There are different types of bruises namely intradermal bruise, subcutaneous bruise, patterned contusion, deep bruise, tram-line contusion, sixpenny bruises, horseshoe-shaped contusion, gravitating or shifting contusions, spectacle hematoma. 

Factors such as the amount of force, pecularities of the victim, resiliency of the area, vascularity of the area, deep/delayed/migratory bruises influence the prominence of the bruise. Also antemortem and postmortem bruising can be distinguished.

If it occurred while being alive, then swelling and color changes can be seen, coagulation of the effused blood into the subcutaneous tissue along with infiltration of the blood into the tissues can be observed. But if decomposition has happened then it is difficult to distinguish between antemortem and postmortem bruises.

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Age of a Bruise

DurationFeatures
FreshReddish in color
Within a few hoursBluish in color
2nd dayBluish-purple coloration
Till the fourth dayBluish-black
4-5 daysBrownish due to the presence of hemosiderin
5-7 daysGreenish due to the presence of haematoidin
7-10 daysYellow due to bilirubin
Within 1 and a half weekYellow color slowly fades in tint
About 2 weeksNormal color is restored.

3. Laceration

A lacerated wound is a form of mechanical injury which is caused by hard and blunt force impact characterized by splitting or tearing of the tissues. The tissues get crushed or stretched beyond the limits of their elasticity.

This causes laceration which disrupts the continuity of the tissues by tearing and not slicing. Passive agents like ground, edge of a pavement or stairs, parts of furniture or a building, vehicles, blunt weapons, and so on can cause a laceration.

Types of Lacerations

  • Split Laceration
  • Stretch Laceration
  • Grinding Compression/Avulsion Laceration
  • Tear Laceration
  • Crush Laceration
  • Cut Laceration
  • Patterned Laceration
  • Boxer’s Laceration

When crushing and tearing are produced due to laceration, there are usually associated abrasions or bruising. Edges of laceration may indicate the direction in which the blow or force was applied. The margins are ragged, irregular, and uneven.

Irregularly torn fibrous tissue, blood vessels, and nerves can also be observed. Bleeding is minimal in lacerated wounds. Lacerations over the hairy area will show hair bulbs crushed or torn and the crushed hair bulb may get thrust into the depth of the wound.  

Conclusion

Sometimes abrasions can be confused with post mortem abrasion, ant bites, pressure sore/bedsore, excoriation of the skin by excreta. Bruises can also be diagnosed differentially as congestion, artificial bruise, purpura, postmortem lividity.

Hence, it is necessary to understand the features of these wounds and what causes such wounds. Sometimes contusions and lacerations can result in the death of a person, hence careful analysis is required to understand whether the injury was the reason for death or not.

The presence of these wounds also indicates whether it is suicidal/ homicidal/accidental which helps in further investigation. 

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