COMPOUND INJURIES

• Jurisdiction: Australia

Introduction ................................................................................................... [33A.1700]

Gunshot wounds ........................................................................................... [33A.1720]

The interpretation of injury patterns Introduction ................................................................................................... [33A.1740]

Injury and cause of death ............................................................................. [33A.1760]

Defence injuries ............................................................................................ [33A.1780]

The unconscious victim................................................................................. [33A.1800]

Injuries after death ........................................................................................ [33A.1820]

Time and sequence of injuries...................................................................... [33A.1840]

The nature of the weapon ............................................................................. [33A.1860]

The direction of force .................................................................................... [33A.1880]

Weapon damage and contamination ............................................................ [33A.1900]

Social and circumstantial factors .................................................................. [33A.1920]

Interpretation of injury ................................................................................... [33A.1940]

Self-inflicted injuries Introduction ................................................................................................... [33A.1960]

Suicidal injuries ............................................................................................. [33A.1980]

Self-mutilation ................................................................................................ [33A.2000]

Self-inflicted injuries mimicking an assault ................................................... [33A.2020]

Scarification ................................................................................................... [33A.2040]

Artefactual injuries Artefactual injuries ......................................................................................... [33A.2060]

Post-mortem lividity or hypostasis ................................................................ [33A.2080]

Artefactual "bruising" ..................................................................................... [33A.2100]

Anal dilatation ................................................................................................ [33A.2120]

Insect abrasions ............................................................................................ [33A.2140]

Animal injuries ............................................................................................... [33A.2160]

Rigor mortis and its forcible disruption ......................................................... [33A.2180]

Artefacts associated with resuscitation ......................................................... [33A.2200]

Artefacts associated with putrefaction .......................................................... [33A.2220]

Sudden natural death ................................................................................... [33A.2240]

Interpretation of autopsy toxicology .............................................................. [33A.2260]

[33A.1700] Introduction

While individual injuries may take the form of one of the types described in previous sections, in many cases the assessment of a wound will reveal it to be composed of a mixture of individual injury subtypes. This is particularly true for certain special wound types such as gunshot wounds, which are described in greater detail at [33A.1720]. Where compound injuries have occurred, one injury subtype may well predominate. For example, where an individual has suffered a knife stab wound, the predominant wound will be an incised wound of stab type. However, there may be some minor abrasion around the edges of the stab wound caused by an irregularity of the surface of the side of the blade, and perhaps some bruising around the stab wound caused by the hilt of the knife being driven against the skin's surface. Another example of a compound injury is a chop wound, as detailed at [33A.1480].

[33A.1720] Gunshot wounds

This group of wounds receives considerable attention in the medical and forensic pathology literature and is a good example of a complex compound injury. The entry of a bullet or a shot into the body usually involves a blunt, penetrating injury that is associated with surrounding abrasion and local bruising. The degree to which these additional components are seen in the wound will vary depending on the type of the projectile used, the distance of the shot, the target area and the angle of contact with the body. For example, a gunshot involving the projectile passing tangentially across the surface of the skin can cause deep grooved lacerations with extensive abrasion of wound edges and wound ends. Even in gunshot wounds, the projectile wounds may be caused by objects other than bullets or shot. For example, where a bullet, passing through the body, strikes bone, secondary missiles in the form of bone fragments may be created. These bone fragments may have extremely sharp edges and together with jagged fragments of the bullet, they may go on to cause incision injuries to internal organs and to the skin at sites of exit. Areas of the body can be damaged by the passage of a bullet even if the bullet does not directly enter that area. For example, the passage of a projectile through the internal soft tissues of the body may create a shock wave that causes temporary and permanent cavities to form within the body's tissues. The disruption of tissue by the shock or pressure wave results in haemorrhage, tissue disruption and death of the soft tissues in the area. Around the main wound tract there may be marked bruising of adjacent tissues that have been subject to a concussive force injury, with the rupture of small vessels leading to diffuse bruising. The dead tissues present a major problem for trauma surgeons in clinical practice, as this tissue must be removed before healing can take place.

In general terms the interpretation of gunshot wounds relates to the terminal ballistics behaviour of projectiles. In addition, however, certain characteristics of the firearm that discharged the projectile can be inferred from the appearances of some projectile wounds, making the interpretation of the wounds an important part of any forensic investigation involving firearms. For a discussion of firearms, see Chapter 86 - Firearms Evidence.

Wounds caused by firearms will vary according to the nature of the projectile, features relating to the cartridge and gun, and factors associated with the ballistics of the firearm projectile. It is important to remember that more than just a bullet or shot emerges from the end of the barrel when a gun is fired. For a detailed discussion, see Chapter 87 - Gunshot Residues. Any dirt within the barrel, together with gas, flame and smoke as well as burnt and unburnt powder and small fragments of bullet, will also be discharged.

These various elements will travel varying distances from the end of the barrel and in the case of smoke may well wrap around the barrel and travel towards the shooter. Components of the fired primer may also be released from the chamber and coat objects close to the weapon, including the hands of the person firing the weapon. Depending on the number of components that strike the target, it may be possible to determine the range at which the gun was fired. While general estimates are given in a number of texts, there is such variability in firearms and ammunition that it is important to test-fire the particular weapon used with the same ammunition at varying distances, to try to recreate the exact forensic features of the wound with respect to the pattern and distribution of these components. If the original weapon and ammunition are not available, then the use of duplicate weapons or weapons of similar type may allow an approximation to be made.

Shotgun wounds can involve both lead shot and wad material striking the body. At very close ranges, soot and other materials may also contaminate the wound. The distance a wad travels from the shotgun will vary depending on the nature of the wad, which may take the form of a fibre disk or a plastic slotted cup. Forensic ballistic test-firing will provide information on the distance the wad will travel, and the marks of wad strike on a body may be used to obtain an estimate of range. At very close ranges, including contact and near contact wounds, multiple lead shot may act more like a solid slug, causing a single large defect in the body. This is because it takes time and therefore distance for the lead shot to separate and start to spread.

Again, the spread of shot in a gunshot wound, together with test-firing of the same or similar weapons and cartridges under controlled laboratory conditions and at different target distances, may provide important information regarding the range at which the shot was fired. The quantity of gas discharged from a shotgun is usually considerable. In the case of hard contact wounds, this gas will enter the body, resulting in pneumatic internal damage to body structures.

The appearance of single wounds caused by rifled weapons (typically handguns and rifles) depends on the range and nature of the projectile involved, as well as some characteristics of the firearm. Entrance gunshot wounds are often classified according to characteristics indicating range. The broad categories are:

• contact wounds;
• near contact wounds;
• intermediate-range wounds; and
• distant (or indeterminate range) wounds.

Contact gunshot wounds occur when the end of the barrel...