Firearms are barreled weapons of any type or description from which a shot, bullet, or another missile can be discharged with some velocity and momentum, and which in the appropriate circumstances can cause injury and death.

20.1: Historical Aspect

Muskets

• Puckle Gun — It is a tripod-mounted, single-barreled flintlock gun fitted with a multishot revolving cylinder.

  • Introduced by James Puckle in 1718.

  • This weapon fired nine shots per minute at a time when the standard soldier’s musket could be loaded and fired but three times per minute.

  • Puckle demonstrated two versions of the basic design:

    • First Variant: Intended for use against Christian enemies, fired conventional round bullets;

    • Second Variant:  designed to be used against the Muslim Turks, fired square bullets, which were believed to cause more severe and painful wounds than spherical projectiles.

Revolvers

• Colt Revolver:

  • Samuel Colt invented the first revolver - named after its revolving cylinder.

  • He was issued a U.S. patent in 1836 for the Colt firearm equipped with a revolving cylinder containing five or six bullets with an innovative cocking device.

Rifles

• Breech Loading Rifle — invented by Captain Patrick Ferguson of Pitfours, Scotland.

• Winchester Rifle — the pump shotgun, and the Colt 45 automatic; designed by John Moses Browning.

  • He is best known for his automatic pistols and was the first one to invent the slide, which encloses the barrel of a pistol and the firing mechanism.

• Modern Assault Rifles

  • The history of the modern assault rifle begins with the German Sturmgewehr used during WW2, the first rifle that could fire a medium size bullet at high rates of fire.

  • In response the U.S. military began developing their own assault rifle; the result was the M16 assault rifle, first issued to American Soldiers in Vietnam in 1968 and designed by Eugene Stoner, a Marine Corps Veteran.

• M1 Semi-Automatic Rifle — invented by John Garand in 1934.

• Johnson Model 1941 Rifle — invented by Melvin M. Johnson Jr.

• Samuel Gardiner: He received a U.S. Patent in 1863 on a “high explosive rifle bullet” in .54, .58, and .69 calibers.

• Rifle Scopes — refractor telescopes used on a rifle; invented by August Fiedler.

• Silencers

  • Hiram Maxim invented the Maxim Silencer or Suppressor that attached to the front of the barrel of a pistol and allowed the firearm to be fired without a loud bang.

  • Invented in 1909, the Maxim Suppressor was the first commercially successful silencer.

Machine Guns

• Gatling Gun — a six-barreled weapon capable of firing a phenomenal 200 rounds per minute; designed by Doctor Richard Gatling.

• Thompson Submachine Gun — it was the first handheld machine gun; invented by General John T.

• Defense Gun — placed on a tripod it was a large revolver with a cylinder behind its single barrel; invented by James Puckle

• Coffee Mill Gun — invented by Wilson Agar and able to sell 54 of it to the Union Army.

• Billinghurst-Requa Gun — comprised a wheeled frame carrying 24 rifle barrels. Once the gun was loaded a single percussion cap was placed on a nipple on the iron frame and fired by a hammer, the flash passing through the frame to ignite all 24 cartridges.

• Gardner Machine — it fired 10,000 rounds in 27 minutes. This impressed military leaders from Britain and the following year the British Army purchased the gun.

• Maxim Machine gun — the world’s first automatic portable machine gun; invented by Hiram Maxim.

  • Trials showed that the machine gun could fire 500 rounds per minute and therefore had the firepower of about 100 rifles.

  • The gun inspired other inventors like:

    • German Army’s Maschinengewehr.

    • Pulemyot Maxima from Russia

    • John Moses Browning

    • Count Odkolek

• Vickers Machine-Gun — it is fitted with interrupter gear, the Vickers was also standard armament on all British and French aircraft after 1916.

• Lewis Gun — it is easier to produce and far lighter than the Vickers, it was used by soldiers on the Western Front and on armored cars and aircraft.

20.2: Important Terms

• Bullets: The projectile.

  • Round Nose — the end of the bullet is blunted.

  • Hollow-point — there is a hole in the bullet that creates expansion when a target is struck, creating more damage.

  • Jacketed — the soft lead is surrounded by another metal, usually copper, that allows the bullet to penetrate a target more easily.

  • Wadcutter — the front of the bullet is flattened.

  • Semi-wadcutter — intermediate between round-nose and wadcutter.

• Buttstock: The portion of the gun which is held or shouldered.

• Calibre: The diameter of the bore of a gun/shotgun.

• Cartridge: Also called a "round". Made up of a case, primer, powder, and bullet.

• Centrefire: The cartridge contains the primer in the center of the base, where it can be struck by the firing pin of the action.

• Chamber: The portion of the "action" that holds the cartridge ready for firing.

• Choke: A constriction of a shotgun bore at the muzzle that determines the pattern of the fired shot.

• Double-action: Pulling the trigger both cocks the hammer and fire the gun.

• Double barrel: Two barrels side by side or one on top of the other, usually on a shotgun.

• Gauge: Refers to the diameter of the barrel of a shotgun really refers to caliber, but is worded as such to refer to a shotgun.

• Hammer: A metal rod or plate that strikes the cartridge primer to detonate the powder.

• Ignition: The way in which powder is ignited. Old muzzle-loading weapons used flintlocks or percussion caps. Modern guns use "primers" that are "rimfire" or "centrefire".

• Lands and grooves: Lands are the metal inside the barrel left after the spiral grooves are cut to produce the rifling.

• Magazine: This is a device for storing cartridges in a repeating firearm for loading into the chamber. Also referred to as a “clip”.

• Magnum: An improved version of a standard cartridge that uses the same caliber and bullet, but has more powder, giving the fired bullet more energy.

  • Magnum shotgun loads refer to an increased amount of shot pellets in the shell.

• Muzzle: The end of the barrel out of which the bullet comes.

• Pistol: Synonym for a handgun that does not have `a revolving cylinder.

• Powder: Modern gun cartridges use "smokeless" powder that is relatively stable, of uniform quality, and leaves little residue when ignited. For centuries, "black powder" was used and was quite volatile.

• Primer: A volatile substance that ignites when struck to detonate the powder in a cartridge. "Rimfire" cartridges have primer inside the base, while "centrefire" cartridges have primer in a hole in the middle of the base of the cartridge case.

• Revolver: Handgun that has a cylinder with holes to contain the cartridges.

  • The cylinder revolves to bring the cartridge into position to be fired.

  • This is "single-action" when the hammer must be cocked before the trigger can fire the weapon.

  • It is "double-action" when pulling the trigger both cocks and fire the gun.

• Rifling: The spiral grooves cut inside a gun barrel gives the bullet a spinning motion. The metal/elevations between the grooves are called a "land".

• Rimfire: The cartridge has the primer distributed around the periphery of the base.

• Safety: A mechanism on an action to prevent the firing of the gun.

• Shotgun: A gun with a smooth bore that shoots cartridges that contain "shot" or small metal pellets (of lead or steel) as the projectiles.

• Sights: The device(s) on top of a barrel that allows the gun to be aimed.

• Silencer: A device that fits over the muzzle of the barrel to muffle the sound of a gunshot. Most work by baffling the escape of gases.

• Single-action: The hammer must be manually cocked before the trigger can be pulled to fire the gun.

• Smokeless powder: Refers to modern gunpowder, which is really not "powder" but flakes of nitrocellulose and other substances. Not really "smokeless" but much less so than black powder.

• Stock: A wood, metal, or plastic frame that holds the barrel and action and allows the gun to be held firmly.

20.3: Firearms and Ammunition

• Ballistics is the science of the motion of projectiles. The term ballistics refers to the science of the travel of a projectile in flight.

• Internal Ballistics: This comprises the study of projectiles/bullets used for firing from firearm weapons. Bullets fired from a rifle will have more energy than similar bullets fired from a handgun.

• External Ballistics: This comprises the study of projectiles in the air.

• Elementary Ballistics: This comprises of the study of the anatomy of the firearm and ammunition. It includes a basic study on firearms.

20.4: Types of Firearms

• Rifled Firearms: These are weapons with elevations on the inside of the barrel that spirals around from one end of the barrel to the other, which can fire missiles or bullets capable of spinning on their own axis thus rendering their aim more accurate and their muzzle velocity higher.

  • Rifling of a Gun: The barrel in a gun of any type is cut into spiral grooves, longitudinally from the chamber to the muzzle end on the inner aspect of its wall.

  • Purpose of Rifling: Rifling of a gun helps the bullet to achieve a gyroscopic movement, which in turn gives a steadiness, during its flight.

  • Pattern of Rifling:

    • Rifling in guns is not uniform. It varies with such factors as the direction of the grooving, which could be the clockwise or anticlockwise magnitude of the rifling spin and the width and depth of the rifling groove.

  • Rifling Marks: These are important markings developed on the surface of the bullet during its transport through the barrel when fired due to friction or rubbing against the lands and grooves.

    • It is considered as fingerprint marks of a gun or a rifle.

• Caliber of a Gun — the diameter of the barrel or bore. It is measured as the distance between two lands of the rifling.

• Classification of Guns/Rifled Firearms:

  • Air/Gas operated guns.

  • 0.303 and 0.22, 0.25, 0.32, 0.39, 0.45, etc. rifles

  • Pistols

  • Revolvers

  • Automatic Pistols

  • Machine Guns

• Gun Cartridge — rifled firearm ammunition, which can be loaded into the chamber of the gun and can discharge the bullet on being fired.

  • Cartridge case — an elongated metallic cylinder made up of cupronickel alloy, and its length varies with each type of gun.

20.5: Shotguns

• Shotguns — are smooth-bore firearm weapons, which can fire missiles or cartridges, which contain multiple small lead pellets at the same time.

• Calibre of a Shotgun:

  • Caliber or bore of a shotgun is the inner diameter of the barrel.

  • Caliber of the shotgun is usually measured by the two methods:

    • Direct method — Here the caliber is determined by measuring the inner diameter of the cylindrical barrel directly in decimals of an inch or millimeters.

    • Indirect method — Here the caliber or bore is determined indirectly by finding out the number of spherical balls of uniform size, prepared from 1 lb (454 gm) of pure lead and each one fitting exactly in the barrel.

    • 6 Bore shotgun: In this, the barrel of the shotgun exactly fits with each of the 6 spherical balls of uniform size prepared out of 1 lb. of pure lead and the number of balls prepared.

    • 12 Bore shotgun: In this, 12 spherical balls of uniform size prepared out of 1 lb of pure lead exactly fit the barrel of the shotgun.

• Choking — a mechanical narrowing mechanism or constriction device at the muzzle end of the shotgun which can control to some extent the area of dispersion of the pellets.

  • Full choke shotgun

  • 3/4 choke shotgun

  • ½ choke shotgun

  • ¼ choke shotgun

  • Improvised cylinder

  • True cylinder is a shotgun with no choking.

Classification of Shotguns

• Depending on the length of the barrel there are two types — a short-barrelled shotgun and a long-barrelled shotgun.

• Depending on the number of barrels there are again two types — a single-barrelled shotgun and a double-barrelled shotgun.

• Depending on the loading route there are two varieties — a muzzle-loading shotgun and a breech-loading shotgun.

• Depending on choking there are several types of shotguns and they are full choked, modified (3/4, 1/2, 1/4) choked, non-choked, etc.

Cartridge of a Shotgun

• Shotgun cartridge: The ammunition for a smooth-bore firearm, which can be loaded into the chamber of the shotgun and can discharge the pellets on being fired.

• Cartridge case — It is an elongated cylinder, made up of cardboard or special paper or plastic composition, the length of which varies with the type of shotgun. It has two ends.

  • Flat closed end is known as the base — this is metallic and has a central depressed area called a percussion cap (primer cup), which accommodates the primer mixture (detonator) next to it within the case.

  • The second flat end, which is the closed terminal end, is comprised of a cardboard disk and holds the pellets under it.

• Gunpowder — It is placed in the compartment immediately next to the detonator at the base of the cartridge and the pellets at the upper end.

• Wad — It is a rounded disk of some thickness and made up of compressed paper, felt, or plastic material, and it physically separates the gunpowder and pellets.

• Pellets — These comprise multiple uniform spherical balls of lead. The cardboard disk and the wad help to keep these pellets as a compressed core in one mass within the cartridge case.

20.6: Wound Ballistics

• Wound ballistics — is the study of tissue penetration of the projectile.

• Ballistics is the science that involves a detailed study of firearm wounds. It includes injuries caused by the bullet and pellets, shot into or through the body.

• Firearm wounds are fundamental of two mains types:

  • Wound of Entry

  • Wound of Exit

• As firearms are of two types, wounds produced by each one are dealt with separately, under the subheadings:

  • Rifled Firearms Wounds

  • Shotgun Firearm Wounds

20.7: Rifled Firearm Wounds

• Rifled firearms wounds — wounds produced by rifled firearms and also known as gunshot wounds.

Heat Combustion Effects

• The flame emerging out of the muzzle end of the gun on firing is responsible for producing a heat combustion effect and the effect of the high temperature of these gases is usually seen on the garments and skin's hair around the wound of entry.

• Effects on garments —These comprise of three characteristic changes, namely

  • Ironing effect — wherein the cloth looks as if freshly pressed with hot iron.

  • Melting effect — especially if the clothing is of synthetic origin.

  • Burning effect — particularly with non-synthetic natural fibres.

• Effects on hair — The changes observed are described as singeing and it is a common finding with contact/close shot range firing.

  • Singed hair will be grossly swollen, curly, fragile, blackish, and emits a peculiar odor.

• Microscopy — shows an increase in the width of the hair, as well as vacuolization within the shaft.

Soiling of the Wound

• Gunsmoke from burnt powder and gunpowder is solely responsible for the soiling effect and it is usually seen around the wound of entry.

• Smudging/blackening — It is due to the deposition of smoke particles, leads or metal of which the missile is made.

• Tattooing/peppering — It is due to the deposition of fine or coarse gunpowder particles, which become truly impregnated into and mark the skin, and cannot be washed or scrubbed off.

Blast Effect

• Blast effects are basically due to the hot gases formed on combustion of the gunpowder and are seen around the wound of entry.

• When the firing is done with the muzzle end held firmly pressed against the site aimed at the gases evolved (namely — CO, CO2, etc.) on combustion of the gunpowder liberate huge pressure.

  • These gases accumulate between the skin and subcutaneous tissues below and in other natural tissue planes, particularly over bony prominences as the skull and induce a blast effect.

• Tearing of skin — due to efforts made by the gases accumulated to come out of the wound of entry.

• Eversion of wound edges — as the gases try to flow out of the wound of entry, the wound edges become everted.

• Muzzle end imprint abrasion — due to the skin being pushed forwards with force and this impinging against the muzzle end of the weapon by the gases accumulated underneath.

• Formation of blood and gunpowder pocket — when the wound of entry is not sufficiently large, blood and gunpowder can get accumulated under the skin and subcutaneous tissue.

• Pressure extrusion — fabric fibers, subcutaneous soft tissues, blood, fat, etc. can extrude out of the wound along with the gases that are emerging out of the wound of entry.

• Soiling of bones (periosteum) and garments (inner aspect) — are due to the soot particles reaching inside of the wound at a contact shot range.

Facial Distortion Effects

• Over expansion or swelling of tissues of the face

• Tears of the skin can occur in front of the ears and along the creases on either side of the mouth and nose, along the inner canthus of the eyes, etc.

• Fractures of the skull and facial skeleton.

Cherry Red Discoloration

• Carbon monoxide gas evolved on burning of gunpowder is the causative factor for this effect. It is usually seen in the tissues around and beneath the wound of entry.

• Carbon monoxide gas can combine with the hemoglobin and myoglobin in the blood/muscle tissues respectively resulting in the formation of carboxyhemoglobin and carboxymyoglobin, which are cherry red in color — resulting in cherry red color muscles around the wound of entry.

Abrasion and Grease Collar

• Abrasion collar — seen as a marginal abrasion around the wound of entry. Depending on the angle of entry made by the bullet,

  • A perpendicular entry of the bullet develops the abrasion collar of rounded shape.

  • An acute angular entry of the bullet develops the abrasion collar of an oblique or oval shape.

• Grease collar — seen on the clothing and is seen as a black deposit, sharply outlined as if printed.

Wound of Entry

1. Contact Shot Range: Here the muzzle end of the firearm is held in—touch or in contact with skin.

2. Close Shot Range: Here the muzzle end of the gun is held about 1" to 3" (2.5- 7.5 cm) away from the target aimed at.

3. Near Shot Range: Here muzzle end of the gun has been held at about 12" to 24" (30-60 cm) away from the target.

4. Distant Shot Range: Here the muzzle end of the gun is held beyond 24" (60 cm) away from the target. The wound apparently resembles a near-shot wound.

20.8: Peculiar Effects of Gunshot Wounds

1. Atypical entrance wound such as:

   • Large atypical entrance wound: When the size of the wound increases to an unusually larger size, more than that of contact shot range or at any other known range.

   • Bullet bruise: Bullet here just hits the skin only and drops down to the ground, without any penetration or wound of entry, producing a bruise alone at the site of impact.

   • Bullet grazes: Here the bullet just hits the skin only at an angle and goes off from the site, without any penetration or wound of entry, producing an abrasion or a laceration depending on the thickness of the skin involved.

2. Ricochet bullet — a peculiar effect on the wound of entry due to the ricocheted or deflected or rebounded bullet.

   • Single ricochet — bullet rebounds only once.

   • Double ricochet — bullet rebounds twice.

   • Inner tangential of entrance side — bullet glides on entering into the skull of the wound of entry.

   • Inner tangential at the contralateral side — bullet hitting the opposite side to the wound of entry glides on it and travels to some distance.

   • Inner tangential at contralateral side and ricochet — bullet after gliding rebounds into another direction.

3. Single entry wound and multiple exit wounds: A bullet after entering into the victim's body may be broken into several pieces by hitting against bony structures and then each fragment ejects out like an individual missile thus producing multiple wounds of exit.

4. Multiple entries and exit wounds, the single bullet recovered: The body of the victim may be in such a position while receiving the crime bullet that in its course of transit, it will enter into and leave the body several times producing several wounds of entry and wounds of exit successively.

5. Entry wound present, but no bullet/no exit wound: The bullet after entering into the body might enter one of the natural passages and may be lost either being coughed out or vomited out or passed out through the anus. It may not be recovered if it gets lodged in the bones.

6. Gutter fracture of skull

7. Tandem/piggy back bullet effect: Here the wound of entry in its depth or along its track shows more than one bullet arranged exactly one behind the other in a row.

8. Frangible bullet effect — an inferior bullet, which on penetrating into the body gets broken up into several fragments and produces severe injuries, by each fragment.

9. 'Dumdum' bullet effect: Here a bullet has a special device at its tip (nose) which, on coming in contact with the target aimed at, bursts open into several fragments, each of which can act like an individual missile and produce fatal injury, over a larger area.

10. Artifacts

    • Rayalaseema phenomena: Here a victim was first killed by stab injury and then to mislead the investigating officer, the criminal stuffed the stab wound with a bullet manually.

    • Souvenir bullet — refers to a condition where in a bullet is preserved for a long time.

    • Magic bullet — the single bullet theory; was introduced by the Warren Commission to explain how three shots made by Lee Harvey Oswald resulted in the assassination of United States President John F. Kennedy.

    • Concealed firearm wounds

20.9: Shotgun Wounds

• Shotgun wounds — wounds produced by shotguns or smooth-bored firearms.

Wound of Entry

Appearances vary depending on several factors:

1. Range or distance of firing

   • Contact shot range

   • Close range

   • Near shot range

   • Distant Range

2. Size of Pellets

   • Smaller pellets — produce wounds which are smaller.

   • Bigger pellets — produce wounds, which are bigger.

3. Types of gunpowder

   • Smokeless — produces no soiling effect of the wound.

   • Black gunpowder — produces a clear soiling effect on the wounds.

Blowback Effect

• Mechanism mainly involved is that in contact shot or close shot range firing, the gases evolved may get accumulated under the skin resulting in a bigger wound of entry, muzzle end imprint abrasion, distortion of the face when shot with muzzle end kept pressed against the roof of the mouth, etc.

• Billiard ball ricochet effect — This is a peculiar effect wherein though the firing is done at close range, the appearance of the wound of entry resembles that of firing done at a greater range beyond 90 cm.

Estimation of Range of Firing by Examining Wound of Entry

• For Ranges up to 3 m: Range multiplied by 31⁄2 roughly gives the spread area diameter in cm.

• For Ranges beyond 3 m: Roughly the spread area is 25 cm per 1 m range.

  • For a Spread Area is 25 cm = Range of firing will be 1m.

  • For a Spread Area is 50 cm = Range of firing will be 2m.

• Exit wound — It occurs only when the shot passes right through and out of the body; the wound will show features like:

  • Margins everted.

  • No soiling, singeing, etc.

  • May be multiple as each pellet or group of pellets might pass out independently.

• Usually shotgun pellets do not exit from the body, except

  • Contact shot wound;

  • Tangential wound where some of the pellets have a very

  • short track through the body and;

  • Thin parts of the body like neck, extremities etc.

20.10: Autopsy Examination of Cases of Firearm Fatalities

Examination of Clothing

• Procedure

  • Clothing is to be removed layer by layer.

  • List all layers and note their condition, any stains, holes, etc. in each item.

  • Record the number and location of bullet holes.

  • Assign a number to each one and describe them in relation to distance from the collar, pockets, etc.

  • Due to creases in clothing, a single bullet can produce more than a single hole.

  • Preferably with a magnifying hand lens try to find out if the fibers of clothes are turned inwards or outwards.

• Further examinations by FSL

  • The clothes collected and examined as above are then dried up in the shade.

  • They are then preserved carefully in clean brown paper envelopes, bags, etc. and sent to forensic science laboratory (FSL) for further examination, to detect the presence of blood, any other biological fluid stains, and gunpowder residues.

• Photographing the clothes

  • Clothes with bullet holes or tracks should be photographed with a scale placed nearby.

  • Infrared photography may be useful in detecting the soot deposits on dark or black coloured garments.

Examination of Wounds

• Wound location — This is done for both wound of entry as well as wound of exit in relation to top of head, the unshod heel, body midline and certain fixed anatomical landmarks.

• Wound description — Describe both entry and exit wounds noting the site, size, shape and other details.

• Excise the wound for further microscopic examination — cut the wound with 2.5 cm. healthy skin around it and a minimum of 5 mm. thickness beneath. This portion of tissue is then put in rectified spirit, labeled and sent to FSL.

Checklist for autopsy in firearm deaths

1. Take an X-ray of the deceased prior to removing the clothing.

2. Recover primer residues from the hands with an acid (10% nitric) moistened swab or adhesive tape.

3. Examine hands for trace evidence, soot and propellant grains, and blood splatter.

4. Examine and remove the clothing without cutting. Use a dissecting microscope to examine clothing defects and wounds for soot and propellant.

5. Examine the body, photograph the wounds if appropriate, and correlate with clothing. Take repeat photographs of the body after cleaning the body and describe the wounds. Note the following while describing the Wounds:

   • Describe each wound completely.

   • Describe wound location relative to (a) body landmarks, (b) body midline and heel or top of the head.

   • Describe the wound appearance by size, shape, abrasion collar, soot, propellant, and wound entry scorching/searing.

   • Describe muzzle end imprint and compare it with an alleged weapon if available at the crime scene/when produced later.

   • Describe the lodged projectile or exit relative to the entrance; describe the general direction of the wound track.

   • Describe any recovered projectile or fragments. Trace the wound tracks and recover the projectiles. Complete the dissection.

6. Try to recover/collect:

   • Propellant grains from the skin surface or wound track.

   • Projectile, taking care not to scratch the surface metal instrumentation such as toothed forceps while collecting. Use rubber-tipped forceps/gloved fingers in the collection of bullets

   • Sample shotgun pellets and all wadding if any.

   • Blood for grouping and blood and tissue for toxicology analysis.

20.11: Gunpowder Residues Tests

• Dermal nitrate test — It is a test for gunpowder particles on the hands of the assailant.

• Harrison and Gilroy test—This is a test for certain elements or compounds such as antimony, barium, lead, etc. found in firearm discharge residue.

• Neutron activation analysis (NAA)—This is a test used for the estimation of the distance of firing and confirming the hands of those suspected of firing a firearm.

• Image analysis of gunshot residue on entry wounds:

  • This method an automated image analysis (IA) technique has been developed to obtain a measure of the amount of gunshot residue (GSR) particles within and around a gunshot wound.

  • Sample preparation and IA procedures were standardized to improve the reproducibility of the IA measurements of GSR.

• Sodium rhodizonate test — This test is performed to detect the particulate lead deposited on surfaces as a consequence of a firearm discharge.

20.12: Medicolegal Questions on Firearm Injuries

• Kinds of the Firearms: A proper examination of the wound of entry and knowledge about the classification of firearms can help in deciding the type of firearm used.

• Range of Firing: A proper description of the wound of entry can help in deciding the range of firing for both gunshot and shotgun wounds.

• Direction of Firing: It can be decided ideally by radiographic examination. However, if probing the wound is allowed, the method of autopsy dissection procedure is more reliable.

• Cause of Death: It is usually due to a vital organ injury in the path taken by a bullet.

• Accident, Suicide, or Homicide?

  • Accidental — Wound could be found anywhere on the victim's body.

  • Suicidal — The wound seen is often singular and noticed on the most vital part of the body, which is usually easily accessible to the victim himself/herself.

  • Homicidal — A wound is usually noticed on the vital parts of the body, which are non-accessible for the victim himself/herself.

Suicidal Firing Deaths Observations

• The majority of suicides (including gunshot suicides) do not leave any suicide notes.

• A contact wound creates a presumption of suicide rather than an accident.

• With rifle and shotgun wounds to the trunk, the trajectory may corroborate suicide.

• Reaching for the trigger with the right hand rotates the body so that the trajectory is right to the left side.

• Suicide handgun wounds occur primarily in the head (80%), the chest (15%), and the abdomen (<5%) being less common.

• Suicidal shotgun wounds show the same site preference as handguns.

• Suicide by multiple gunshots is uncommon but not rare.

• A suicide victim may "test fire" the weapon before inflicting the fatal shot.

• In about 20% of suicides, the weapon is found clutched in the hand. Rarely an orange-brown discoloration of the palm due to iron deposition from the barrel may be seen; the stain cannot be wiped away.

• Occasionally high-velocity impact blood spatter will be deposited on the back of the hand steadying the muzzle and the back of the firing hand.

• The hand holding the muzzle may show soot deposition on the radial margin of the forefinger and the adjacent surface of the thumb and the radial half of the palm due to muzzle blast.

• Contact wounds to cotton or cotton mixture cloth from medium and large caliber weapons typically produce cruciform tearings; with synthetic materials, there are burn holes with scalloped melted margins.

• Tearing is less prominent with the smaller amounts of gas from rimfire ammunition.

Position of Weapon

• In suicides usually, the weapon may be still held firmly in the victim's hand (cadaveric spasm).

  • There are also sites of election for suicidal wounds, which are the mouth, head, and front of the chest. It is still unusual for a woman to commit suicide with a firearm.

• In accidental cases, the weapon is found at the scene of the crime.

• No weapon is detected at the scene of the crime if it is a case of homicide.

• It is essential also to be able to assess how the person might have had the access to the gun and to the ammunition for it.

• In the case of long-barreled weapons, it is essential to discover whether or not the weapon could have been fired by the deceased and measurement of arm span, etc is essential.

Medicolegal Importance of Bullet

1. Crime Bullet — a bullet collected at surgery or autopsy, from the body of a victim alive or dead.

2. Test bullet — a bullet that is fired from a weapon suspected of being involved in a crime; the test firing is into a gunny bag fixed into a deal wood box.

3. Exhibit bullet — a crime/test bullet, which is presented in the court as evidence.

Crime Scene Instructions

1. Handle the body as little as possible thus avoiding artifacts and loss of trace evidence.

2. The hands of the victim may be covered inside a paper bag in order to preserve trace evidence.

3. Transport the body in clear plastic sheeting or a body bag to preserve trace evidence and avoid contamination.

20.13: Taxonomy of Explosives

1. High-order explosives — produce a defining supersonic over pressurization shock wave.

   • Examples: TNT, C- 4, Semtex, nitroglycerin, dynamite, and ammonium nitrate fuel oil (ANFO).

2. Low-order explosives — create a subsonic explosion that does not produce over pressurization.

   • Examples: Pipe bombs, gunpowder, and most purely petroleum-based bombs such as Molotov cocktails or aircraft improvised as guided missiles.

Explosive and incendiary (fire) bombs are further characterized based on their source:

• Manufactured weapons — implies standard military-issued, mass-produced, and quality-tested weapons.

  • These are exclusively HE-based.

  • Terrorists will use whatever is available-illegally obtained manufactured weapons or improvised explosive devices (IEDs) that may be composed of HE, LE, or both.

• Improvised weapons — describes weapons produced in small quantities, or the use of a device outside its intended purpose, such as converting a commercial aircraft into a guided missile.

20.14: Blast Injuries

Mechanisms of Injuries

• Amount and composition of the explosive material.

• Surrounding environment.

• Distance between the victim and the blast.

• Delivery method if a bomb is involved.

• Other environmental hazards.

Types of Blast Injuries

• Primary blast injury — is caused solely by the direct effect of blast overpressure on tissue. Air is easily compressible, unlike water.

• Secondary blast injury — is caused by flying objects that strike people.

• Tertiary blast injury — is a feature of high-energy explosions. This type of injury occurs when the victim is flown/blown through the air and strikes other objects.

• Miscellaneous blast-related injuries — encompass all other injuries caused by explosions.

20.15: Other Injuries

1. Ear Injury: Tympanic membrane (TM) perforation is the most common injury to the middle ear.

   • Signs of ear injury are usually present at the time of initial evaluation and should be suspected for anyone presenting with hearing loss, tinnitus, otalgia, vertigo, bleeding from the external canal, TM rupture, or mucopurulent otorrhea.

2. Abdominal Injury: Gas-containing sections of the gastrointestinal tract are most vulnerable to the primary blast effect. This can cause immediate bowel perforation, hemorrhage, mesenteric shear injuries, solid organ lacerations, and testicular rupture.

3. Brain Injury: Primary blast waves can cause concussions or mild traumatic brain injury (TBI) without a direct blow to the head.

   • Symptoms of a TBI may not appear until days or weeks following the injury or may even be missed when patients appear fine, even though they may act or feel differently.

4. Burns Injuries: These are due to the temperature of the explosive gases, which can cause flash burns.

5. Disruptive Injuries: Victims who are very close to the exploding bomb or if they are in the process of carrying the bomb on their person or in a car, maybe shattered into several pieces, and these pieces may be scattered over an area of 200 m.

6. Air Blast Hurl Injuries: It can hurl the victims against walls or toss them through the air in various directions thereby causing them to sustain very severe blunt force injuries.

7. Flying missile injuries: Occur due to numerous missiles within the bomb or pieces of fragments of objects nearby, e.g. gravel, glass, mound, brick, etc.

8. Injuries due to Falling Masonry: It is usual that due to a blast, building or heavy structures around the blast may also get wrecked and heavy objects such as beams, walls, roof, etc. may collapse and land on the victims and may individually contribute to several mechanical injuries.

9. Effects due to Toxic Gases in a Bomb Blast: Toxic gases like CO, CO2, etc. in a bomb blast can also kill the victim when inhaled.

10. Distance Blast Injuries: These occur at solid/ fluid or air/fluid interphones with disruptions at these points and are particularly prominent in the ears, in the lungs, and in the intestines.

20.16: Injuries Due to Antipersonnel Landmines

• Landmines — Any ammunition placed under/on or near the ground or other surface area and designed to be detonated or explode by the presence, proximity or contact of a person or vehicle.

• Antipersonnel landmines — small in size and are specifically targeted for human beings on foot.

  • They are difficult to locate or detect and are activated by direct pressure.

• The explosion of mines causes hideous mutilation, deaths, and devastating injuries.

• The small antipersonnel mines disable those who traverse their paths.

• These landmines lie dormant until a person, a vehicle or an animal triggers their firing mechanism. T

• They are blind weapons that cannot distinguish between the footfall of a combatant from that of a non-combatant.

Patterns of Injury

• Pattern 1: The victim triggers buried mines by stepping on the device.

  • They usually have a traumatic amputation of part of the lower limb, with less severe injuries elsewhere: mud, grass.

  • Fragments of mine, boot and the remains of the foot were blown upwards into the leg, genitals, buttocks and the contralateral are causing a secondary infection.

  • These injuries are the most severe as there is close contact between the device and the foot when it explodes.

• Pattern 2: The pattern of wounding is more random and consists of multiple shrapnel wounds from the mines triggered near the victim.

• Pattern 3: The mine explodes while being handled resulting in injury to the hands and face.

  • Eye injury is sustained from fragments, mud, or sand thrown up by the explosion; many victims lose one or both eyes.

Type of Foot Injury

• Grade 1 Injury: The injury occurs through the forefoot.

  • There is no damage to the ankle and subtalar joints.

  • The resulting disability is minimal.

  • This type of injury is uncommon.

  • Amputation can be carried out through the metatarsal bones giving the patient a useful stump.

• Grade 2 Injury: The injury takes place through the distal row of tarsal bones and is accompanied by damage to the long flexor tendons on the dorsal aspect of the foot.

  • The ankle and subtalar joints, calcaneum, and heel pad are intact.

  • An amputation at this level will result in a viable stump, but on weight-bearing, the stump goes into plantar flexion as a result of which it becomes difficult to fit a prosthesis.

  • These victims invariably end up with below-knee amputation.

• Grade 3 Injury: The injury occurs through the calcaneum with complete destruction of the heel pad.

  • They require a below-knee amputation.

• Grade 4 Injury: This is the most common and most severe injury where the entire foot is blown off above the ankle joint.

  • It is unfortunate that this is the commonest injury seen.

  • Treatment is a below-knee amputation.

The three objectives of primary amputation for mine injuries of the foot. In order of priority are:

• To excise dead and contaminated tissue and to remove accessible foreign bodies.

• To be able to perform delayed primary sutures.

• To leave a stump that is acceptable for a fitting prosthesis.

Prevention of Antipersonnel Mine

• Public awareness: The medical profession should document the mental and physical suffering experienced by victims of land mines.

• Mine survey and eradication: Casualties should be reduced by clearing and destroying the mines that have been already laid.

• Ban on the use of antipersonnel mines.

20.17: Emergency Management Options

• Follow your hospital and regional disaster plan.

• Expect an upside-down triage, with the most severely injured arriving after the less injured, who typically bypass EMS triage and go directly to the closest hospitals.

• Double the first hour's casualties for a rough prediction of the total first wave of casualties.

Mass Casualties Predictor

• To predict the total number of casualties your hospital can expect, double the number of casualties the hospital receives in the first hour.

  • Total expected casualties = (No. of casualties arriving in 1hr window) × 2.

• Obtain and record details about the nature of the explosion, potential toxic exposures and environmental hazards, and casualty location from police, fire, EMS, ICS commander, regional EMA, health department, and reliable news sources.

• When trying to determine how many casualties a hospital can expect after a mass-casualty event, it is important to remember that casualties present quickly and that approximately half of all casualties will arrive at the hospital within a one-hour window.

20.18: Patterns of Hospital Use

• Within ninety minutes following an event, 50% to 80%of the acute casualties will likely arrive at the closest medical facilities. Other hospitals outside the area usually receive few or no casualties.

• The less-injured casualties often leave the scene under their own power and go to the nearest hospital. As a result:

  • They are not triaged at the scene by emergency medical services (EMS).

  • They may arrive at the hospital before the most injured.

  • On average, it takes 3-6 hours for casualties to be treated in the emergency department (ED) before they are admitted to the hospital or released.