Sharp Force Injuries: Characteristics, Mechanisms, and Medico-Legal Aspects
Sharp Force Injuries: An Overview
Mutilating Injuries
The instrument attacks a salient part of the body. If the weapon is very sharp, it is common to join or traction avulsion mechanisms.
Atypical Incised Wounds
1. Abrasions or Erosions
Caused when the instrument is merely tangentially touching the skin, causing an erosion or partial detachment of the epidermis.
2. Zigzag or Bridging Wounds
These are due to the characteristics of the skin or region. Skin folds in loose areas form easily.
Irregular Wounds
The lack of edge of the weapon or the existence of dents, more or less modified form of incised wounds.
Prognosis
Depending on the instrument (fineness of edge and cleaning of the weapon) and area wounded, bleeding or air embolism can be fatal. Bleeding is constant in this type of wound. Healing of these lesions is usually rapid, resulting in linear or elliptic scars, more or less elongated.
Sharp Instruments and Injuries
The damaging part consists of a lamina more or less tapered narrow and crossed by one, two or more sharp edges. The number of edges defines monocortantes (single-edged), bicortantes (double-edged), or pluricortantes (multi-edged) instruments. Common instruments in medicolegal practice are knives, art knives, daggers, stilettos, etc.
Mechanism of Action
The mode of action of short, sharp instruments involves both sharpness and cutting.
Characteristics of Stab Wounds
Stab wounds are similar in part to sharp and partly to incised wounds.
Inlet
Atypical. The morphology varies with the shape of the instrument.
1. Flat Bicortante Blade
The wound is shaped like a crack, similar to that of a cutting tool, but deeper.
2. Flat Monocortante Blade
It is shaped like a fissure, one of the two extremes is more acute, often with an obvious tail, while the other is blunt and rounded.
3. Thick Monocortante Blade
The characteristic of this type of knife is the presence of a ridge, opposite the cutting edge. One end is sharp and tailed, and the other is square.
4. Pluricortante Blade
The inlet has a star-shaped appearance, with as many points as the instrument has sharp edges.
5. Atypical Spade Wounds
The main causes are in the instrument or how to place the angle of the wound. If the cutting edge is very sharp and has no tail, the occurrence of the victim or the gun moving.
Journey (Path of the Wound)
Various forms:
- It can be single or multiple, as the instrument has made more than one insight, even though she never left at all.
- It can be perpendicular to the plane of the skin or oblique. In this case, the bevel produced helps diagnose the direction of travel from outside.
- It can be in the pouch or full channel, resulting in the latter case, a hole. The different planes crossed by the path of stab wounds have always targeted the corresponding holes in the same sense, which differentiates them from puncture wounds.
Exit Hole
Not always present. Usually smaller than the input, especially with sharp, thinner weapons sharpened at the tip.
Prognosis
Same guidelines as for puncture wounds. In some regions (neck), very serious complications can occur.
Medico-Legal Problems with Sharp Weapons
Diagnosing Vital vs. Postmortem Origin of Wounds
Key data: the existence of external or internal bleeding, air embolism in wounds of the neck veins, the retraction of the edges.