FIREARM INJURIES

By Dr. Naveen

shotgun

rifle

These are injuries caused by high velocity projectiles, calle

d bullets or pellets.They produce punctured wounds.

Types of firearm weapons (guns)

1) Rifled guns - The term “rifle” comes from the riflings or groovings made on the inner surface of the barrel. On the inner surface of the barrels of these guns, parallel grooves (usually 4-7 in number) are made which run spirally, all along the bore.

Rifled guns are comparatively more powerful guns. Rifled gun cartridge contains one bullet as the projectile.

2) Smooth bored guns or shotguns : In these guns the inner surface of the barrel is uniformly smooth.

Injuries in case of rifled weapon (bullet injury)

There is a single punctured wound of entrance. It travels deep inside the body, injuring organs in its track and sometimes makes an exit wound.

1. The wound of entrance

1) shape and diameter

The wound of entrance is circular when the bullet strikes the body surface perpendicularly.

It is oval, when the bullet strikes the body at an angle.

This wound (wound of entrance) is smaller when the firing is from a close range (except contact wound).

It is slightly larger when the firing is from a long distance.

2) abraded or contused collar

While the bullet enters the body through the hole made by the nose of the bullet, the surface of bullet faces a friction with the skin surrounding the hole (wound of entrance), causing abrasion or contusion of the frictioned area, around the wound of entrance, termed abraded or contused collar.

3) dirt or grease collar

Around the abraded or contused collar, there is a dirt or grease collar, made by the metallic dust and grease on the surface of the bullet, which the bullet inherits when it passes through the length of the bore of the barrel (grease is used in the inner surface of the barrel to prevent rusting, and metallic dust is produced due to the friction between the bullet and inner surface of the barrel when the bullet travels inside the barrel).

3) The wound of entrance is inverted and there is no protrusion out of fat through this wound.

The abraded or contused collar and the grease collar tell about the direction of firing .

2. The depth and track of the wound After entering the body the bullet may run a

straight course or it may get deflected and take a different course due to obstruction by the tissue, mostly a bone.

If the affected part of the body is covered with clothes then, the depth of the wound near the wound of entrance will show presence of fabrics torn out from the clothes and pushed inside the wound by the bullet. In bullet injury, usually there is less haemorrhage near the wound of entrance.

3. The wound of exit

1) The wound through which the bullet comes out of the body is usually slightly larger than the wound of entrance, when the gun is fired from a short distance. The wound of entrance is smaller when the bullet is fired from a short distance, because in that case the bullet possesses high velocity.

But when fired from a long distance, the exit wound is slightly smaller than the wound of entrance . The wound of entrance is larger when the bullet is fired from a great distance as, then the bullet possesses a low velocity.

2) The wound of exit is everted, with protrusion of fatty tissue through the wound.

3) The margin is irregular.

Contact wound in case of rifled weapon In case of contact wound, there will be muz

zle impression around the main wound, in the form of abrasion or depression. The effect of fire, hot gas, smoke and unburnt and semiburnt gunpowder will be present in the depth of the wound near the wound of entrance, instead of their effects being present around the wound.

Due to expansion of the gas coming out of the muzzle end and entering inside the depth of the body tissue, there will be greater destruction of the tissue with a large wound.

If the contact wound is on the head, then bursting of the cranial cavity may occur with exposure and expulsion of the brain matter.

Examination of gunshot injury cases A. In case of living In pellets (shotgun ) injury, the problem is o

ccasionally more than bullet injury. This is because of dispersion of the pellets in the body. The pellets may be distributed in widespread area. But fortunately, often the depth of the wounds are less with less involvement of the internal vital organs due to less penetrating capacity of the pellets.

The part of the body apparently injured with possible extent of the pellets to deeper tissue, should be subjected to X`ray examination.

X`ray examination will help exact location of the pellets, which is necessary for both legal and medical purposes.

Examination of the injured

1. General condition of the injured.

2. The part involved, extent and severity of the injury.

For these, radiological examination may be necessary. X`ray examination is also necessary for therapeutic purposes. A gunshot injury case is better examined on the operation table.

In case of shot gun injury, many a ti

mes the superficially lodged pellets are left as such without disturbing, particularly when many of them are lodged sporadically at distant places. If such pellets are compatible with continuance of life and normal functioning, then their removal by surgery may be considered as unnecessary step, just to cause further trauma.

3. Examination of the clothing

It is important to examine the clothing to the presence of recent tear or bullet hole and blood and other stains.

4. Examination the place of occurrence of the bullet injury may at times be necessary, which may be helpful to know the direction of firing etc.

B. Postmortem examination of a case of death due to firearm injury

The size and shape of the entrance and exit wounds should be noted. Mark of contact with the muzzle is also an important finding. Once the bullet or a pellet is traced (which becomes very easy if the body is X`rayed prior to the starting of the postmortem examination ), it has to be removed from the body cautiously. It is recommended that bullets or pellets should be removed with the help of rubber-tipped forceps and not with the bare metallic tips of the forceps.

The bullet or the pellets so recovered, need not be washed and should instead be preserved along with the blood stain over them, being wrapped with cotton, in a clean glass jar. The jar should be properly labeled and sealed and sent to the Forensic Science Laboratory. If fragments of a bullet have been recovered, then all the available fragments of the bullet should be preserved.

The number of bullets, fragments or pellets recovered and preserved should be mentioned on the label of the glass container. In case of contact wound by shotgun, along with pellets, the wad and the discs should be searched out from the track of the wound and preserved.

Materials to be preserved during postmortem examination in cases of death due to firearm injuries

1. Bullet, fragment of bullet or pellets.

2. Skin from around the wound, for chemical identification of the unburnt gunpowder and the type of grease (available from the grease or dirt collar), which help to identify the firearm weapon used. If the unburnt gunpowder detected from the skin around the wound tallies with that present in the inner surface of the barrel of a gun which is suspected to have been used to injure the victim, then that becomes a strong corroborative finding.

3. Clothing

Differences between wound of entrance and exit

( page 192)

Points of difference Wound of Entrance Wound of Exit

1.Size Smaller when near, larger when distant

Larger when near, smaller when distant

2. Margin Inverted Everted

3.Singeing, blackening, burning, tattooing Present Absent

4. Abraded or contused and grease collars Present Absent

5. Foreign fabrics of cloth etc Enters in the wound Nothing such

6. Protrusion of fat Absent Present

7. Bright redness due to formation of COHb Present Absent

8. Impression of muzzle Present in contact shot Absent

9. Bursting effect In contact shot may be present Absent

Medicolegal informations available from a firearm injury

1. Nature of death due to firearm injury – Death due to firearm injury may be suicidal, homicidal or accidental.

Suicidal: 1) elective sites (palate, right temple in case of a rt. handed person), 2) usual weapon(short,hand-rest weapons), 3) Often the entrance wounds are contact wounds with presence of the impression of the muzzle around the wound of entrance. 4) The gun may be held in the tight grip, in a state of cadaveric spasm of the hand used. And other suicidal support.

Homicidal , accidental ( no specificity)

2. The direction of the firing It is better to try to assess the direction of th

e firing from the dispersion of the pellets in cases of shotgun injuries and from abraded /contused and grease collars, in case of bullet injuries by rifled weapons.

3. Distance of firing In case of bullet injury (rifled gun), the dist

ance of firing can be assessed from : 1) Effects of fire, smoke, burnt and unburnt gun

powder, when firing is from a short or near distance.

2) Beyond the distance covered by the influence of these, it is very difficult to assess the precise distance of the firing. Only a vague idea can be formed from the diameters of the wound of entrance and the wound of exit.

Usually, when the firing is not from a great distance, the wound of entrance should be smaller than the wound of exit. But if the firing is from a long distance, the wound of entrance may be equal or even larger than the wound of exit.

3) As in case of shotgun injury, impression of the muzzle will indicate contact firing.

4. Identification of the firearm weapon used.

1) The gunpowder used in the ammunition (cartridge), can help identification of the weapon used.

If by chemical examination, the nature of the gunpowder present at the inner surface of the barrel and those around the wound of entrance or the corresponding part of the clothing of the victim are found to be same, then it is an indication that the suspected gun might have been used in the particular occasion.

2) As in case of gunpowder, if the grease material from over the grease collar around the wound of entrance or the corresponding part of the clothing (in case of bullet wound), tallies with the grease material, used to keep the inner surface of the barrel of the suspect gun clean then , this finding also serves as a linking line between the use of that particular gun in causing the particular wound.

3) Comparative study of the bullet recovered from the dead body and the test bullet fired from the suspect gun

Such a comparative study may be confirmatory to conclude whether a particular gun was actually used or not.

1) Primary markings – These are the marks engraved on the surface of the bullet due to lands and grooves present on the inner surface of the barrel of a rifled gun, which are similar in the barrels of all the guns of the same make.

Hence, these marks on the surface of the bullet, which are parallel and spiral according to the line of the grooves and lands on the inner surface of the barrel, will be similar on all bullets fired from any rifled gun of the same make.

2) Secondary markings – These marks on the surface of the bullet are caused due to certain individual features of the inner surface of the barrel like, minor projections or elevations or depression are specific of a particular gun and not common to all guns even of the same make.

If these marks on the body of the test bullet and those on the body of the recovered bullet tally in their dimensions and curvature, then it can be more or less conclusively opined that, the bullet causing the death of the victim was fired from the gun examined.

5. Identification of the assailant

Dermal nitrate or paraffin test is recommended for the identification of the assailant. Paraffin impression from the medial surface and the base of the thumb and lateral surface and the base of the index finger of the right hand of a right handed accused is taken and is subjected to the test for the presence of nitrite, performed with the reagent diphenylamine.

In case of recent use of a gun, if the hand is contaminated with nitrogenous compound of the gunpowder or priming mixture, then bluish discoloration of the relevant parts of the paraffin cast will be there due to leakage of the gas from the chamber through the defective breach mechanism, during a fire.

The test may be negative even though one round was fired by the accused, if there is no chance of leakage of the gas through the breach mechanism or if the assailant has thoroughly washed his hand after using the gun or used gloves while using the gun.

Conversely, the test may give a false positive reaction even if a gun has not been used by the accused person, if his hand gets contaminated with his own body fluid like urine, which contains nitrogenous compounds.

Now-a-days, for the fallacies of the nitrous test, test for metal present in the priming mixture which also contaminates the hand, is recommended. Trace of the primer metals may be detected by SPECTROPHOTOMETRY or NEUTRON ACTIVATION ANALYSIS.

EXPLOSIVE

Terrorism and warfare lead to many deaths from explosive devices. In military bomb, shell and missile explosions , the release of energy may be so high that death and disruption from blast effects may occur over a wide area, though the energy falls off rapidly as the distance from the epicentre increase.

When an explosion occurs, the generation of huge volumes of gas, expanded by chemical interaction and great heat,causes a compression wave to sweep outwards.At the origin, this is many times the speed of sound, but rapidly slows down.The pure blast effects cause either physical fragmentation, disruption and laceration of the victim, from high pressure and hot gas striking the body. A minimum pressure of about 700kilopascals is needed for tissue damage in humans

There may be pressure effects upon the viscera, which are far more damaging eg. lungs and alimentary canal .Ruptures and haemorrhage of these zones is the classical blast lesion.

For more casualties, fatal and otherwise, are caused by secondary effects of explosive devices, especially in the lower-powered terrorist bombs. These include:

1 Burns, both from the near effects of the explosion and secondary burns from conflagrations started by the bomb.

2 Missile injuries from parts of the bomb casing and from adjacent objects and fragments projected by the explosion.

3Peppering by small fragments, debris and dust propelled by the explosion. These can cause multiple abrasions, lacerations and bruises and discolour the skin from impacted dirt.

4 All types of injuries due to collapse of buildings, roofs, ceilings, etc.due to structural damage from the explosion.

5 Injuries and death from vehicular damage or destruction, such as decompression, fire and ground impact of bombed aircraft and crash damage to cars, trucks, buses, etc.

If a near or massive explosion disrupts one or more bodies, then identification of the fragments is essential, not least to determine how many victims were killed –a task which can be extremely difficult. The task resembles that after a mass disaster such as an air crash, where many bodies may be both disrupted into hundreds of fragments and burned as well.

现场地面落叶

面目全非

炸断的足

面目全非

内裤上的破

口

家具下压着两具尸体

女尸

残存的女阴

躯干被破坏

衣服上的破口

男尸的损伤