Morphological features of stab wounds. The ability to establish a weapon (weapon) according to the individual characteristics of these damages

Sharp tools is a collective concept, it includes all those tools (objects, weapons) that have a sharp edge, called a blade, and a sharp end.

According to the characteristics of the device and the mechanism of action, there are 5 types of sharp tools: cutting, stabbing, piercing-cutting, chopping, sawing.
There is only one feature common to all sharp tools: damage is caused by the direct impact of these objects on the human body, and tissue dissection takes place, according to all other features of the action of each of these tools differ from each other in mechanogenesis and morphology.

Damage from cutting tools

Cutting tools have a sharp edge - a blade that has a damaging effect (straight razors, safety razor blades, table knives, etc.). The mechanism of action of the cutting tool is as follows: its blade separates (cuts) with pressure on the skin and underlying tissues while being pulled soft tissue, a cut wound is formed.

The signs of cut wounds are as follows:
1. Smooth and non-planted edges.
2. Sharp ends of wounds. In those cases when, when removed from the wound, the trauma instrument changes its direction, an additional incision is formed, and one end of the wound takes the form of a "dovetail".
3. The length of the cut wounds almost always prevails over the depth and width. The depth of cut wounds is determined by the sharpness of the blade, the force of pressure and the nature of the damaged tissue. The bone is an almost insurmountable obstacle to the cutting tool.
4. For cut wounds, their gaping is characteristic due to the elasticity of the skin and the contractile action of the muscles.
5. The shape of the cut wounds is fusiform, lunar, but always linear (when the edges are brought together).
6. Cut wounds are accompanied by significant external bleeding, the magnitude of which is predetermined by the caliber of the crossed vessels. With deep cut wounds, such as the neck, bleeding from large vessels leads to acute massive blood loss, which ends in rapid death.
In this case, blood aspiration and air embolism can be observed.

Stabbing damage

Stabbing weapons have a more or less long blade ending in a sharp point. Depending on the shape of the cross-section of the blade, the tool can be conical, cylindrical (with a sharp end), pyramidal with faces, most often with three or four. Typical representatives of piercing tools are: a needle, an awl, a nail, a pitchfork, "sharpening", weapons - a bayonet, stylet, rapier, sword.

The mechanism of action of piercing weapons: the sharp end of the weapon cuts or tears the skin under pressure, and the blade of the weapon, when immersed, pushes or tears the tissue, a puncture wound is formed, the elements of which are: an entrance hole, a wound channel and, sometimes, an exit wound hole (for through wounds) ...

Morphological signs of puncture wounds the following.
1. The presence of an inlet and a wound channel, and sometimes an outlet.
2. The outer dimensions of the entrance skin wound are usually less than the cross-section of the tool blade at the level of its immersion.
3. The shape of the entrance wound hole largely depends on the shape of the cross-section of the blade of the tool, it does not repeat it, but it retains skin breaks according to the ribs and their number (but no more than 6, if the number of ribs is more than 6, then they are no longer displayed) ... From cylindrical and conical piercing tools, the shape of the entrance hole is oval rather than round.
4. The edges of the wound can have a sagging in the form of a narrow band up to 0.1 cm.
5. The walls of the wound are even and smooth. The wound canal in the initial part can be closed with lobules of adipose tissue.
6. Unlike cutting tools, stabbing tools with a strong impact can cause damage to flat bones in the form of perforated fractures, and from the side of the outer plate, the shape of the fracture can reflect the shape of the cross-section of the injury tool.
7. Minor external bleeding and, often, massive internal bleeding (with injuries of the heart, liver, large vessels) is characteristic of puncture wounds.

Damage from piercing and cutting tools

Stabbing and cutting tools combine the properties of both stabbing and cutting, and damage from them combines some signs of both stab and cut wounds.
A stab-cut wound consists of the following elements: an inlet in the skin, a wound canal extending from it and sometimes, if the wound is through, and an outlet in the skin.

Signs of stab wounds the following.
1. Slit, fusiform, arched shape. If the piercing-cutting tool had a one-sided sharpening of the blade, then the greatest divergence of the edges will be at the edge where the butt of the tool acted. Wounds from guns with a backing with a thickness of more than 2 mm will have one sharp horse, and the other U-shaped. In those cases when the tool, when extracting it from the wound, rotates around its axis, in addition to the main one, there is also an additional incision, and one of the ends of the wound will have the shape of a "dovetail".
2. The edges of the stab and cut wounds are usually even, without sedimentation, sometimes with slight sedimentation, according to the action of the butt.
3. The wound canal in more or less dense tissues (for example, in the liver) has a slit-like shape, its walls are even and smooth, fatty lobules of subcutaneous tissue can protrude into the lumen of the wound canal in its initial part. The length of the wound channel will not necessarily correspond to the length of the weapon's blade, since the blade may not be completely immersed in the wound, and when fully immersed in the pliable part of the body (abdomen), the length of the wound channel may be greater than the length of the injury weapon.
With a strong impact with a piercing-cutting tool on a flat bone, its perforated fracture may form.

Chopping damage

Chopping tools (axes, cleavers, mowers, etc.) have a more or less sharp blade and a relatively large mass. The mechanism of occurrence of damage from chopping tools is based on a blow, in which the blade cuts the tissue, and the side parts of the tool push apart the edges and walls of the resulting chopped wound. The nature and morphological features of chopped wounds depend on the force of the blow, the mass of the weapon, the sharpness of the blade, and the characteristics of the damaged part of the body.

Signs of chopped wounds the following.
1. The edges of the chopped wounds in the skin will be smooth, without deposits, if the blade of the tool was sharpened. If the blade of the tool was blunt, then the edges of the wound will be serrated, sometimes finely scalloped, sagged.
2. The walls of the wound channel of the chopped wound are smooth and even. As you approach the bottom of the chopped wound, signs of tissue crushing can be detected, which is especially pronounced when examining damaged bones. On this basis, it is possible to determine the direction of the blow in cases where the limb or its parts are completely cut off.
3. The ends of chopped wounds have characteristics depending on which part of the ax was struck. If the blow was inflicted only by the middle part of the blade, then the wound will be slit-like, and its ends will be sharp. When the blow is struck with the toe or heel of an ax, one end of the wound will be sharp, and the other will be U-shaped. When the entire rebound blade is immersed in the wound, both ends of the wound will be U-shaped.
4. The chopped wound in its cross-section reflects the shape of the tool, which is a wedge. If the wound was inflicted at an angle close to a straight line, the wound will be rectilinear (slit, oval); if the angle is closer to an acute one, then the wound will be arched and, the sharper the angle, the steeper the arc will be.
5. Bone damage is characteristic of chopped wounds. If the lesions are located on the head, then they can be slit-like or splintered, with light blows, notches are formed, without damaging the inner plate of the bone. With strong blows, not only the bones of the skull are damaged, but also the membranes and the very substance of the brain.

The features of mechanogenesis and morphology of damage from mechanical factors considered in this chapter enable the attending traumatologist to correctly diagnose damage, which has a certain value in choosing and implementing the most rational method of treatment.

"Damage surgery"
V.V. Klyuchevsky

Among the crimes against life and health, provided for by the criminal legislation of Belarus, bodily injuries of varying severity occupy a special place.

The law assigns the establishment of the fact of their presence, nature and severity to the forensic medical examination. In accordance with the Rules of forensic medical examination of the nature and severity of bodily injuries in the Republic of Belarus (hereinafter referred to as the Rules), a forensic expert, when assessing the nature and duration of a disease or impairment of functions associated with damage, must proceed from objective medical data. The forensic examination of determining the nature and severity of bodily injuries is carried out by medical examination. However, practice shows that often the initiators of the appointment of examinations provide only the medical documents available in the case materials, where bodily injuries are recorded by doctors at different stages of medical care. Medical documents for an expert are the only source of information about bodily injuries in cases when a citizen comes for an examination after the end of treatment and healing of injuries.

Health workers often have difficulty identifying and describing injuries, limiting themselves to general phrases such as “multiple bruises on the face and trunk.” In this case, the type, exact location of damage, their number, shape, size, color, etc. are not indicated. On the basis of such a description, an expert cannot resolve questions about the type, localization, mechanism and duration of the formation of bodily injuries.

According to the Rules, an expert, in case of unclear clinical picture or insufficient clinical and laboratory examination of a person, should refrain from determining the severity of bodily injury and state the reasons why he cannot do this in the conclusions.
Doctors of health care institutions most often have to deal with injuries caused by criminal, domestic, transport and sports injuries (in the form of abrasions, bruises, wounds).

Abrasion - violation of the integrity of the epidermis. Indicates the place of application of the traumatic force, the direction of its effect, the age and the mechanism of formation.

Bruise - hemorrhage in the skin and deep-lying tissues. It also indicates the place of application of the traumatic force, the direction of its impact, the age and the mechanism of formation; can display the shape of the object that was struck.

Wound - violation of the integrity of the skin and deep-lying tissues. Indicates the place of application of the traumatic force, the direction of its effect, the age and the mechanism of formation; in the wound may
some indication of the item that caused it will appear. The description of wounds by doctors of medical institutions for the solution of expert questions is of particular importance. As a rule, the experts seek medical help before undergoing a forensic examination. If the patient's condition requires it, doctors surgically treat the wound (excision of soft tissues, stitches, etc.), and an expert without information contained in medical documents cannot assess bodily injuries.

When describing localization, it is recommended to adhere to the main anatomical landmarks and conditional topographic line axes. If the lesion is on the limbs, the surface (anterior, posterior, external, internal, antero-external, etc.) and the level of location (conventionally dividing the limb into upper, middle and lower third) should be indicated. To clarify
localization on the chest, it is necessary to report in the projection of which rib and along which conditional topographic line (midclavicular, paravertebral, anterior axillary, mid-axillary, posterior axillary, scapular, paravertebral) the damage is located.

Scheme describing abrasion and bruising:
1. Exact localization.
2. Shape (linear, round, oval, irregular oval, etc.), direction (vertical, horizontal, oblique-vertical from top to bottom, left to right, etc.).
3. Dimensions (length, width in cm).
4. Condition of the bottom or covering crust, the color of the abrasion crust, the color of the bruise.

The surface of the abrasion is at first moist, sinks in relation to the level of the surrounding skin; then it becomes covered with a crust formed by coagulated plasma and blood. The crust gradually rises to the level of the skin, then rises above it, as epithelialization peels off and disappears. At the site of the former abrasion, a site of hyper- or hypopigmentation remains for some time.
The color of the bruise changes color over time sequentially from red-purple, blue, purple, brown, greenish to yellow.
Features of the state of the surrounding soft tissues (swelling, hyperemia, with the imposition of blood, soil, etc.).

Examples of abrasion description:
On the front surface of the right lower leg in the middle third, against the background of swelling of the soft tissues, there is a skew-vertical (top to bottom, right to left) oval abrasion measuring 5-3 cm, covered with dense red-brown
a crust located above the level of the surrounding skin.
On the right lateral surface of the chest, in the projection of the 7th rib along the mid-axillary line, there is a horizontal linear abrasion of 6.2,20.2 cm with a moist dark red bottom located below the level of the surrounding tissues. The skin is covered with blood around the abrasion.
Examples of descriptions of bruising:
On the eyelids of the right eye, there is an irregular oval horizontal purple bruise measuring 56.5 cm.
On the back surface of the right elbow joint there is a rounded brownish-green bruise 2.5 cm in diameter, against which there is a horizontal oval abrasion 1.50.5 cm under a dense brown crust located above the level of the surrounding skin.

Scheme for describing wounds:
1. Localization.
2. The shape of the wound (linear, spindle-shaped, L-shaped, etc.); direction; does it change after the edges are brought together; the presence of a soft tissue defect (minus tissue).
3. Dimensions (length and width in cm); if the wound channel does not depart from the wound, its depth is also indicated.
4. The nature of the edges (even or uneven, the presence of sediments, foreign inclusions, whether there are breaks (their localization, direction, size), etc.).
5. The nature of the ends (rounded, acute-angled, are there any breaks (their localization, direction, size), etc.).
6. Content (what it is filled with, the presence of foreign particles, their features), which is the bottom.
7. The condition of the surrounding skin (abrasions, bruising, dirt, the presence of foreign inclusions, gunpowder, etc.)
8. Description of the wound channel (general direction, length, through which tissues and organs it passes, what is filled with, ends blindly or penetrates into the cavity, etc.)

An example of a description of a bruised wound: in the area of \u200b\u200bthe left zygomatic arch there is a horizontal gaping wound of an irregular oval shape measuring 1.50.4 cm without a soft tissue defect, with the greatest depth in the center 0.3 cm. The edges of the wound are uneven, the ends are rounded, the wound lumen is filled with blood clots; bottom - subcutaneous fat.

An example of a cut wound description: on the posterior surface of the chest on the right, in the area of \u200b\u200bthe scapula, there is a skew-vertical (top to bottom, left to right) linear wound measuring 3.00.2 cm. Its edges are even, the ends are acute-angled. A thin linear abrasion 3.50.1 cm with a moist red sinking bottom departs from the lower end of the wound as its continuation. During the examination, bleeding continues from the wound; during the revision, it was found that its maximum depth at the upper end was 0.4 cm.

An example of a description of a stab wound: on the outer surface of the middle third of the left shoulder there is a horizontal fusiform wound 1.20.4 cm in size without tissue defect, with smooth edges, acute-angled ends. From the wound in the forward direction (from outside to inside, from left to right) a wound channel 3.5 cm long departs, which blindly ends in the muscles of the shoulder; liquid blood and convolutions in the lumen.

Example input description gunshot wound: on the anterior surface of the chest on the left, in the 4th intercostal space, along the midclavicular line, there is a round wound with a diameter of 0.8 cm. The edges with uniform dark brown sedimentation up to 0.2 cm wide, when they are brought together, a skin defect is determined. The skin around the wound has a round blue-red bruise 1.5 cm in diameter with focal subcutaneous emphysema.

An example of a description of an exit gunshot wound: on the posterior surface of the chest on the right, along the vertebral line at the level of the 7th thoracic vertebra, there is a vertical slit wound 1.5 ра0.2 cm in size, without a skin defect. The edges of the wound are uneven, slightly turned outward, without precipitation.

(Based on the materials of the letter from the Main Department for the Coordination of Official Activities of the Central Office of the State Committee for Forensic Examination in the Ministry of Health of the Republic of Belarus No. 7/2249 dated 11.08.2014.)



Damage from piercing and cutting tools, those. combining the signs of both piercing (point) and cutting (blade) objects. Stab-cut wounds caused by various knives, the damaging part of which - blade - according to their properties, it allows them to be divided mainly into two types: finnish knives and daggers... Features of knife blades used in everyday life are very variable and in some cases do not fit the specified classification. In the former, one edge of the blade is sharpened in the form of a blade, and the other is blunt, called a butt. For daggers (daggers), both edges of the blade are sharpened in the form of a blade.

The piercing-cutting objects, in contrast to the piercing ones, penetrating into the body with a sharp end, do not split, but cut the tissue with a razor or blades.

The damage consists of inlet, wound channel,and with through wounds - and outlet.

In damages, one should distinguish between the main cut formed when the blade is immersed, and the additional cut formed when the tool is removed due to pressure on the blade (when there is no pressure on the blade, there is no additional cut). By examining the edges of the wound, bruising, sagging, drying and contamination (rubbing border) can be detected.

Bruises (with skin sedimentation in a limited area) are formed when the blade is completely immersed from the action of protruding parts - a stopper, a beard (blade base), a handle. A bruise is used to judge not only full immersion, but also the presence of the listed parts on the tool.

A narrow strip of sedimentation is found along the edges of the main cut and with incomplete immersion of the blade. Settling is better expressed on the side of the inclination of the implement.

Over time, under certain conditions, the wound is exposed to drying out, a dense brownish-yellow or brownish-red border is formed along the edges of the wound and in places of injury. Drying out can distort the original shape of the wound.

The shape of the ends of the wound depends on the properties of the damaging blade. The blade forms an acute-angled end; butt (1–2 mm thick) - rounded, U-shaped, or with tears and notches (G, T, M-shaped). There is sedimentation and drying on the side of the butt action, which is revealed by a histologically parallel cut to the skin surface.

Damage to the hair along the edges and at the ends of stab wounds is characteristic. A straight butt damages the hair, and in the place of action of blades or a beveled butt, the hair overlaps the ends of the wound in the form of bridges. If a chisel was used, then the hair is crossed over the entire length of the wound.

Damage to bones from the dissecting action of the blade, butt and side surfaces can be in the form of through holes, notches, cuts or scratches.

Notches - minor damage to relatively thick bones from the introduction of only the tip of the blade (allow you to determine the end of the wound channel).

Incisions - the result of the sliding of the point or blade on the bone (up to cuts). When the butt slides, defects from bone abrasion are sometimes formed, which make it possible to judge its thickness (width).

The shape of the blade is established by casts (made of paraffin, paste "K", latex), radiographs and large-scale schemes of the wound channel in relatively dense organs. The thickness of the butt is determined by the width of the U-shaped end. The sharpness of the blade is judged by the evenness of the edges of the holes and, especially, by the condition of the ends of the crossed threads along the edges of the damaged clothing.

The sequence of inflicting multiple injuries is not established in all cases. It is necessary to compare the features of the damage with the known circumstances of their infliction: deformation of the blade and other damage to the knife when hitting a bone or objects in clothes are possible; there may be a border of dirt and a blood border of rubbing in subsequent damage to the outer surface of thick, dense or multi-layered clothing.

When deciding whether damage has been inflicted by one's own or an unauthorized hand, it is important: location, depth, severity and number of injuries; the direction of the wound channels; the presence of traces of struggle and defense, damage of other origin.

Zakirov Takhir Ravilievich. Features of the stab and cut wounds arising during free fall of a person on a fixed blade of a knife: dissertation ... Candidate of Medical Sciences: 14.00.24 / Zakirov Takhir Ravilevich; [Place of defense: GOUVPO "Moscow State University of Medicine and Dentistry"]. - Moscow, 2008 .-- 116 p .: ill.

Features of stab and cut wounds that occur when a person free falls on a fixed knife blade / Zakirov T.R. - 2008.

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ZAKIROV Takhir Ravilievich

SPECIFIC FEATURES OF PUNCH-CUT WOUNDS ARISING WHEN A MAN FREE FALL ON A FIXED KNIFE BLADE

Moscow - 2008

The work was carried out at the Department of Forensic Medicine of the State Educational Institution of Higher Professional Education “Izhevsk State Medical Academy of Roszdrav”.
Scientific adviser: Doctor of Medical Sciences, Professor Viter Vladislav Ivanovich
Official opponents: Doctor of Medical Sciences, Professor Sergey Sergeevich Abramov; Doctor of Medical Sciences, Associate Professor Nagornov Mikhail Nikolaevich
Lead organization: State Healthcare Institution "Bureau of Forensic Medicine" of the Department of Healthcare, Moscow
The defense will take place "___" 2008 in _ hours at a meeting of the dissertation council DM 208.041.04 at the State Educational Institution of Higher Professional Education "Moscow State Medical and Dental University of Roszdrav" at the address: Moscow, st. Dolgorukovskaya, 4, building 7, (premises of the Department of History of Medicine). Mailing address: 127493, Moscow, st. Delegatskaya, 20/1
The thesis can be found in the library of the Moscow State University of Medicine and Dentistry (127206, Moscow, Vuchetich St., 10a).
Abstract has been sent out "_ »_ __ _2008 year.
Scientific Secretary of the Dissertation Council, Candidate of Medical Sciences, Associate Professor T.Yu. KHOKHLOV

The urgency of the problem

Fatal injury from the action of piercing and cutting weapons among mechanical damage ranks third and accounts for about 18% of forensic medical examinations. In addition to deliberate damage with sharp objects (Syrkov S.M., 1976; Khokhlov V.V., Kuznetsov L.E., 1998), accidents are often observed as a result of the use of piercing and cutting objects in everyday life (Ignatenko A.P., Lysy V.I., 1973; Baldaeva V.G., 1970; Savostin G.A., 1971, etc.). The data of the medical literature indicate that among the injuries with sharp objects, which ended in a fatal outcome, the share of accidents is about 2-4% (Ivanov I.N., 2000), which is associated, among other things, with falls on them. Analysis of the forensic medical literature made it possible to establish that there are practically no studies devoted to the study of the characteristics of injuries resulting from a person falling on a knife blade (Ivanov I.N., 2002-2004).
In cases of crimes involving the use of sharp objects and the infliction of single stab and cut wounds by people suspected of committing a crime, the explanation is often used that there was an accident, for example, a fall on a knife, especially when there are no eyewitnesses to the incident (Ivanov I.N., 2004) ... In this regard, in the practice of forensic medicine, there are objective difficulties in deciding the possibility of wound formation as a result of impact or when a knife falls on the blade.
Currently, a number of methodological approaches are proposed to resolve the issue of the possible infliction of a stab wound as a result of a knife strike or falling on a fixed knife blade, but there are no objective forensic criteria. Most often, it is recommended to perform situational examinations (Gedygushev I.A., 1999) or conduct an expert experiment (Ivanov I.N., 2004).

Purpose of the study:

Improving the quality of differential diagnosis between a stab wound caused by impact with a sharp object and a wound resulting from the free fall of a person on
a fixed knife blade based on a complex of objective morphological features.

Research objectives:

1. To develop a technique for modeling stab-cut injuries of the chest when a person falls on a fixed knife blade;
2. To investigate the signs of stab and cut wounds on the basis of expert and experimental material;
3. To establish the objective morphological changes in stab injuries, allowing to differentiate wounds caused by impact from wounds that have arisen when falling on a fixed knife blade;
4. To offer practical recommendations for the examination of single penetrating stab-cut wounds of the chest for forensic medical experts.

Scientific novelty

The scientific novelty of the research lies in the fact that for the first time in forensic medicine, a comprehensive study of stab-cut wounds of the chest caused by various methods was carried out, and new differential diagnostic signsallowing to determine the mechanism of injury.

Practical significance

The practical significance of the work lies in the fact that, based on the study of morphological signs of stab-cut wounds of the chest in comparison with the design features of the blade, additional diagnostic expert criteria were obtained, a formula was developed, the use of which makes it possible to objectify the mechanism of causing damage by a sharp object (RF patent for invention
No. 2308887 dated October 27, 2007).
A technique has been developed that makes it possible to obtain experimental stab and cut injuries of the chest as a result of free falling onto a fixed knife blade.
In the study of stab and cut injuries of the chest caused by a fall of a person on a knife blade, diagnostic signs were obtained that confirm this mechanism of injury.

The following provisions are brought to the defense:

1. Stab and cut wounds arising from blows with sharp tools have certain morphological features, the formation of which is caused by the characteristics of the traumatic object.
2. Experimental injuries resulting from a fall of a person on a fixed knife blade have morphological signs that differ from stab wounds caused by blows with sharp objects, which is associated with a different mechanism of their formation.
3. A comprehensive study of the stab-cut wound of the chest and the design features of the trauma tool allows one to more accurately judge the features of the mechanism of damage.
4. On the basis of the statistical analysis, a mathematical formula has been developed that allows to determine with a high degree of reliability the mechanism of inflicting damage to the chest with a sharp weapon.

Dissertation approbation

The main results of the work were reported and discussed at the certification cycles held in 2007 at the faculty of advanced training of the Izhevsk State Medical Academy, at the scientific and practical conference "Actual problems of improving the activities of the preliminary investigation bodies of the system of the Ministry of Internal Affairs of Russia" in the Izhevsk branch of the Nizhny Novgorod Academy of the Ministry of Internal Affairs of the Russian Federation in 2007 ; at the scientific-practical conference "Actual problems of criminalistics and forensic examinations" in the Izhevsk branch of the Nizhny Novgorod Academy of the Ministry of Internal Affairs of the Russian Federation in 2007; at meetings of the Society of Forensic Physicians of the Udmurt Republic (2005-2007)

All material presented in the dissertation was received, processed and analyzed by the author personally.

Implementation

Scientific and theoretical provisions of the dissertation work are implemented in studying proccess Department of Forensic Medicine, State Educational Institution of Higher Professional Education "Izhevsk State Medical Academy of Roszdrav". Practical recommendations and the main provisions of the research implemented into practice
GUZ "Bureau of Forensic Medicine" of the Udmurt Republic, GUZ
"Kurgan Regional Bureau of Forensic Medicine", OGUZ
"Chelyabinsk Regional Bureau of Forensic Medical Examination" and the State Institution of the Komi Republic "Bureau of Forensic Medical Examination".

Publications

Volume and structure of the thesis

The thesis is presented on 142 pages. It consists of an introduction, a literature review, a chapter of material and research methods, four chapters of our own research, conclusions, conclusions, practical recommendations, a list of used literature, including 112 sources, including 13 foreign and an appendix. The thesis contains 57 figures and 7 tables. The application is designed in the form of tables. The topic of the thesis has a state registration
№ 01.2.006.12417.

Research material

The studies were carried out on the basis of the state health institution "Bureau of Forensic Medicine" of the Udmurt Republic.

To study the frequency and characteristics of stab and cut injuries, the data of medical and forensic studies from 632 acts for 2005 were analyzed. Of these, 53 studies were selected, carried out in cases of single stab-cut wounds of the chest and known instruments of causing injury.

• the length of the victim's body (contained in the extract from the forensic medical examination report);
• morphological signs of a stab-cut wound (the nature of the edges and ends of the wound, the presence of sedimentation of the edges, acute-angled and opposite ends of the wounds);
• localization of stab and cut wounds;
• the length of the wound on the skin;
• the depth of the stab and cut wound;
• the presence of damage to the bone skeleton of the chest in the area of \u200b\u200bthe stab wound;
• the direction of the wound channel;
• the length and width of the knife blade submitted for examination;
• the presence of a heel and a beard at the blade of the examined knife;
• difference (in cm) between the depth of the wound channel and the length of the blade.

Information from the acts of medico-forensic research was processed by statistical research methods.
The experiments were carried out on biomnequins (corpses of men aged 32 to 60 years old and one woman aged 59 years old, persons without a fixed abode and having no close relatives) entering the court morgue of Izhevsk.
The simulation of the introduction of a fixed knife blade into the chest as a result of free fall was carried out using the created setup, which is a metal stretcher with a length
212cm, weighing 8.5kg for carrying people. The biomanikin was laid down and fixed on a stretcher. To standardize the experimental conditions, the lower end of the stretcher was fixed to the metal frame by a hinge mechanism. A metal chair with a back was rigidly attached to the same horizontal frame on the opposite side, on which there was a small movable platform with a variable angle of inclination at a height
82cm from the floor, to which the knife blade was fixed. The chair could be displaced in relation to the platform to adjust the area of \u200b\u200bthe blade penetration into the chest. In the experiments, three knives were used, which are most often used in everyday life: a Finnish factory-made knife, a penknife and a kitchen knife.

Knife No. 1. A factory-made hunting knife with a total length of 24.4 cm. The length of the blade is 13.4 cm, butt is 0.22 cm thick at the base. Between the handle and the blade there is a metal stop 4x1.8 cm. The blade is sharpened on both sides, ends with a beard 1.3 cm long, which protrudes 0.2 cm above the blade.The width of the blade at the base is 2.6 cm.

Knife No. 2. The penknife is made of white metal with a total length of 17.4 cm. The handle is 9.9 cm long. The end part of the handle near the blade ends with a limiter 0.7 cm high at the top and 0.7 cm at the bottom. A blade with a length of 7.5 cm is attached to the handle by a hinge mechanism.The blade is straight, a U-shaped edge with a thickness of 0.25 cm at the handle. The blade is double-sharpened, at the handle passes into the heel 0.1 cm high and 1 cm long. The blade is fixed lock in the form of a spring-loaded metal plate. The width of the knife blade is up to 1.15 cm.

Knife No. 3. A kitchen-type, handicraft-type knife, with a total length of 25.8 cm, consists of a metal plate, one part of which is presented in the form of a 15.6 cm long blade, to the other two plastic overhead plates are attached with rivets. The end of the handle, adjacent to the blade, is beveled at a slight angle from top to bottom. The blade of the knife is straight, has a U-shaped butt, 0.2 cm thick. The blade is sharpened on both sides. The width of the blade at the handle is 2.9 cm.

The blades of the knives were fixed in such a way that the blade of the knife and part of the handle completely protruded above the plane of fall to a length of 4-5 cm.

To fix the removed skin flaps, the method proposed by G.L. Servatinsky (1988): 2% formalin solution prepared in saline. The 22 stab-cut wounds obtained as a result of the experiments were visually examined on the corpse before the removal of the skin flap, after the removal of the skin flap, visually and using the MBS-10 stereoscopic binocular microscope at various magnifications before fixation and after fixation of the skin flaps.

The following data were registered and studied:

• - body length of the biomanikin;
• - body mass of the biomanikin;
• - localization of stab and cut wounds;
• - the length of the wound on the skin;
• - morphological signs of a stab-cut wound (the nature of the edges and ends of the wound, the presence of precipitation of the acute-angled and opposite ends of the wounds);
• - the depth of the stab wound;
• - the presence of damage to the bone skeleton of the chest in the area of \u200b\u200bthe stab wound;
• - blade length of the knife used;
• - the difference (in cm) between the depth of the wound channel and the length of the blade.

To assess the revealed signs, a binary system was used, if the studied sign was reflected in the wound, it was coded with the number "1", if not - "0".

In addition, in addition to injuries from the free fall of the biomnequin on the knife blade, stab wounds were received on the biomnequins from the blows of the investigated knives. The resulting injuries were examined visually under an MBS-10 stereomicroscope at various magnifications.

Photographing of experimental injuries was also carried out using a digital camera "Konica Minolta Z 10"; video filming of the infliction of experimental damage using a video camera; analysis of photograms and video filming data with computer image processing, allowing slow frame-by-frame viewing of the mechanism of damage.

For the comparison group, data from 53 medico-forensic studies were taken, carried out in cases of single stab and cut wounds and known instruments of injury.

To analyze the results obtained, we used statistical methods supplied with the Microsoft Excel program and discriminant analysis carried out using computer program SPSS for Windows (Statistical Package for the Social Scienc).

Main research findings

In the forensic departments, forensic medical research is most often carried out about damage to clothing and the body caused by piercing-cutting tools, among which various types of household knives and piercing-cutting weapons prevail. One of the important aspects of the study was a comparison of the signs of stab wounds known in the forensic medical literature and the frequency of their occurrence with those on the example of forensic medical examinations in the State Institution of Forensic Medicine Bureau of the Udmurt Republic. For a comparative study, cases with one or two stab wounds on the chest of different anatomical localization were selected, when one of the main issues in these examinations was the identification of the presented tool. The analysis of the acts of medical and forensic research showed that the studies carried out on the fact of the death of men accounted for 60.9%, women - 39.1%. All puncture wounds examined in the forensic department were analyzed by us to compare the sizes of the trauma tools and their trace-forming parts with the features of the injuries caused by the knives presented for the study. At the same time, the following data were obtained: all stab wounds had smooth edges; in the only case, one end of the wound had an M-shape, the opposite - U-shaped, in the rest - one end was acute-angled; the opposite - U-shaped (34 wounds), rounded (12 wounds), M-shaped (5) or acute (2), which was due to the peculiarities of the traumatic effect of a piercing-cutting object. A total of 50 knives for various purposes were presented at the MKI, the blades of which had a length of 7.1 cm to 22.9 cm, the average length was 13.5 ± 0.98 cm.The width of the investigated blades was from 1.3 cm to 3, 5 cm, the average blade width was 2.2 ± 0.1 cm. These data were taken into account when choosing the blades of the knives used as tools in the course of the experiments. The length of the wound channels ranged from 4 cm to 17.5 cm and averaged 9.2 ± 0.9 cm. In 7 cases, the depth of the wound channels exceeded the length of the blade by a distance of 0.5 cm to 3.3 cm, in the rest, the depth of the wound channel was less than the length of the blade, the difference between them averaged 4.4 ± 1.02 cm. Of the 50 knives presented on the MCI, the presence of a heel was recorded in 5 knives, a beard - in 11 knives. The deposition of the acute-angled end was not observed in the studied wounds, and the opposite end was found in 20 wounds (37.7%). The knife-edge mark has been described in two forensic studies. Thus, the action of the heel or barb was not reflected in the edges and ends of the investigated wounds due to incomplete immersion of the blade or immersion of the heel (beard) did not change the shape of the blade end.
Out of 53 studies, only in one case the possibility of inflicting a stab-cut wound of the chest with a piercing-cutting object presented for research was recognized as unlikely, in all other cases the possibility of causing a stab-cut wound with a knife,
submitted for examination, was not excluded.

The study of extracts from the reports of the examination of corpses, reflected in the research part of medico-forensic studies, showed that in no case in the area of \u200b\u200bthe stab wound was damage to the skeleton in the area of \u200b\u200bthe entrance wound or at some distance from it.

The next stage of our research was the infliction of experimental wounds as a result of the free fall of the biomnequin on the blades of knives most often used in everyday human activities.

Experimental damage with a hunting knife (No. 1). Anthropometric data of biomanikins, the height of the experimental wounds, the depth of the wound channel, and the localization of wounds are presented in Table 1.

Table 1

Characteristics of observations in cases of experimental damage with knife No. 1

expertise			wound location	wound location (cm)	blade length (cm)	wound channel (cm)
			3 intercostal space along the mid-clavicular line
			2 intercostal space on the mid-clavicular line on the left
			in the 2nd intercostal space between the peri-sternal and mid-clavicular lines
			in the region of 3 ribs between the mid-clavicular and anterior axillary lines
			in the region of 4 ribs along the anterior axillary line
			in the 3rd intercostal space between the peri-sternal and mid-clavicular lines
			4 intercostal space on the mid-clavicular line on the left
			3 intercostal space along the peristernal line on the right

As a result of the free fall of the biomanikin on a hunting knife (No. 1)
there was always a complete immersion of the blade in the chest, entrance
wounds on the skin had signs characteristic of this type of injury (smooth edges, sharp one end and U-shaped opposite). In addition, at the edges of the entrance stab-cut wound, features characteristic of the complete immersion of the blade were displayed in the form of abrasions from the action of the blade of the knife blade and the end part of the handle; the depth of the wound channel in cases where it does not occur along its course bone structures, as a rule, exceeded the length of the blade by 2.0-8.5 cm; sometimes in the area of \u200b\u200bentrance stab wounds, straight (extensor) fractures of one or more ribs were formed, characteristic of the action of a blunt object. The features of the edges and ends of some wounds, the presence and shape of sediments are shown in Fig. 1a, 1b.

and)

b)

Fig. 1. Schematic representation of an experimental stab and cut wound.

The shading shows the sedimentation in the area of \u200b\u200bthe ends of the wounds.

Experimental injuries sustained using a pocket knife (No. 2).
The conditions for performing the penknife experiments were standard. The height of the biomnequin's fall above the level of blade fixation was 30cm and 50cm, the blade penetration occurred to its entire depth perpendicular to the front surface of the chest or at a slight angle (up to 5º), control was carried out using a protractor. The results of experiments with knife No. 2, anthropometric data of biomanikins, characteristics of the received wounds and their localization are presented in Table 2.

table 2

Characteristics of observations in cases of causing experimental injuries with knife No. 2

expertise			wound location	wound location (cm)		wound channel (cm)
			3 intercostal space on the mid-clavicular line on the left
			in 2 intercostal space on the left between the mid-clavicular and periosternal lines
			in the 2nd intercostal space along the mid-clavicular line on the right
			in the projection of 4 ribs along the mid-clavicular line on the right

As a result of the free fall of the biomnequin on the blade of the penknife, it was always completely immersed in the chest, entrance wounds on the skin had signs characteristic of this type of injury (smooth edges, a sharp one end and a U-shaped opposite) or were modified due to deformation of the acute-angled end heel action. The severity of deformation of the ends of the wound depends not so much on the action of the object on the object of injury, but on the reverse action of the body on the traumatic object. This was established during the study of video materials with computer image processing, which made it possible to study the mechanism of the formation of a stab-cut wound during slow (frame-by-frame) playback. As a result of the fall of a person, due to the elasticity of the tissues of the chest, the fallen body bounces off the obstacle and again falls on it (up to 3 times), while the amplitude of movements gradually dies out. At the edges of the entrance stab-cut wound, features characteristic of the complete immersion of the blade in the form of abrasions from the action of the end part of the handle can be displayed. In fig. 2a and
2b shows some damage, the shape and localization of sediments obtained using a penknife (indicated by the shaded area). These signs are more clearly manifested due to the characteristics of the knife (limited protruding elements of the handle or blade retainer, large heel or beard, etc.). The depth of the wound channel in cases where no bone structures are encountered along its course, as a rule, exceeds the length of the blade by a distance from 3 cm to 5.5 cm; in the area of \u200b\u200bentrance stab and cut wounds, damage to the cartilaginous part of the ribs, characteristic of the action of a sharp or blunt object, can form.

Fig. 2. Schematic representation of an experimental stab and cut wound.

The shaded area shows the shape of the deposits in the area of \u200b\u200bthe ends and edges of the wounds.

Experimental injuries sustained using a kitchen knife (No. 3). To inflict experimental injuries, we used one of the kitchen knives, removed from the scene and received by the forensic medical examination bureau for a comparative study. The height of the biomnequin's fall was 30cm and 50cm, the blade was inserted perpendicularly to the front surface of the chest or at a slight angle (up to 5º) to its entire depth, control was carried out using a protractor. The results of experiments with knife No. 3, anthropometric data of biomanikins, characteristics of the received wounds and their localization are presented in Table 3.

Table 3

Characteristics of observations and results of experimental injuries with knife No. 3

expertise			wound area	wound location (cm)	blade length	wound channel (cm)
			3 intercostal space between the mid-clavicular and periosternal lines on the left
			1 intercostal space on the mid-clavicular line on the left
			in the 4th intercostal space on the left along the mid-clavicular line
			in the area of \u200b\u200b5 ribs between the mid-clavicular and anterior axillary lines on the right
			in the 3rd intercostal space on the left along the mid-clavicular line
			in the 2nd intercostal space along the peri-sternal line on the right
			in the 4th intercostal space between the midclavicular and anterior axillary lines on the left
			in the 5th intercostal space along the peristernal line on the right

As a result of the free fall of the biomnequin on the blade of a kitchen knife, it was always completely immersed in the chest, entrance wounds on the skin had signs characteristic of this type of injury (smooth edges, sharp and U-shaped ends, smooth walls). In the edges and in the area of \u200b\u200bthe ends of the entrance stab-cut wound, features characteristic of the complete immersion of the blade were displayed in the form of abrasions from the action of the end part of the handle; the depth of the wound channel in cases where no bone structures were encountered along its course, as a rule, exceeded the length of the blade by a distance from 1.4 cm to 6.4 cm; in the area of \u200b\u200bthe entrance stab and cut wounds, damage to the ribs, characteristic of the action of a blunt object, could form. The signs revealed when using a kitchen knife in the area of \u200b\u200bsome entrance stab and cut injuries and their shape are shown in Fig. 3a, 3b.

Fig. 3. Schematic representation of the experimental wound. The shaded area indicates precipitation.

The severity of signs such as abrasions, bruising at the edges and ends of injuries, deformation of the ends of wounds arising from the action of the beard, heel of the blade, limiter or end part of the handle depends
not only from the action of the tool on the object of injury, but also of the object on the tool, which can be repeated due to damped oscillations of the chest wall, as a result of the elasticity of the tissues of the human body and the shock-absorbing abilities of the chest skeleton. For the same reason, branching of the end part of the wound canal can be observed.
To establish the features of the trail-forming part of the blades selected for the production of experiments, experiments were performed - shock effects were applied to the chest area. In this case, biomnequins of men were used.
Knife blows No. 1 (hunting) were applied to the front surface of the exposed chest from a small height with a sharp wrist blow, perpendicular to the chest to the entire depth of the blade. As a result of the experiments, wounds were obtained that were located on the left and right of the chest. The wounds were spindle-shaped, with smooth edges (see Fig. 4).

Fig. 4. Schematic representation of the experimental wound, blade end on the left.

Percussion injuries with a pocket knife No. 2 were applied without swinging along the anterior surface of the exposed chest. Stab and cut wounds were oval in shape. The immersion of the blade was complete. Their edges were even, one end was sharp, the opposite U-shaped. One of the corners of the butt end was more pronounced, not sieged. Around the blade end, sagging was observed on the skin due to the immersion of the blade heel. The edges of the wounds are without sediment (see Fig. 5).

Fig. 5. Schematic representation of an experimental wound caused by a penknife strike. The shading shows the embedding of the acute-angled end. The butt end is on the right.

Experimental injuries with kitchen knife No. 3 were inflicted on the exposed front surface of the chest from a short distance, without swing, with the blade fully immersed. Entrance wound holes were slit-like. One end of the wounds had an acute-angled shape, the opposite - U-shaped. The skin around the butt end was slightly hardened. (see Figure 6.)

Fig. 6. Schematic representation of an experimental wound caused by a blow of a kitchen knife. On the right, there is an acute-angled end; shading shows the shading of the butt end.

Stab and cut wounds caused by the impact of sharp objects are accompanied by certain identifying features. Full immersion of the blade into the body, despite the presence of the design features of the knife (beard, heel, complex configuration of the stopper, etc.), does not always form any changes in the wound.

Discriminant analysis of two groups of data (experimental, obtained when the biomanikin falls on the blade and data from the ICI acts).

For the study, we prepared two summary tables. One contained information from 53 acts of medico-forensic research for 2005, the other - the results of experiments. 7 signs were subjected to a comparative study. The grouping of cases was used as a classifying factor. Initially, the analysis took into account such parameters as body length, sedimentation of the acute-angled and opposite ends of wounds, the length of the knife blade and the depth of the wound channel, the difference between the length of the blade and the depth of the wound channel, the presence of damage to the bone skeleton of the chest in the area of \u200b\u200bthe entrance puncture wound. The body weight of the biomnequin in the comparative analysis is not
was used because in practice, in most cases, the weighing of the bodies of the deceased is not carried out. In experimental injuries, the prevalence of the depth of the wound channel over the length of the blade was indicated by a positive number, and in the injuries described in the ICI reports, the prevalence of the length of the blade over the depth of the wound channel had a negative value.
The first group included experimental data, the second
- data of medico-forensic research. To register signs, a binary system was used: if it was reflected in the wound, then it was encoded with the number 1, if it was absent - 0.
As a result of the analysis, it was found that the average length of the blade in the experiments was 11.89 cm; the average depth of the wound channel is 16 cm; the average difference between the length of the blade and the depth of the wound channel is 4.1 cm. Fractures of the bone skeleton of the chest were observed in
45.5% of cases. Complete immersion of the knife blade was reflected in the morphology of experimental entry wounds: sedimentation from the action of the beard or heel was expressed in the area of \u200b\u200bthe acute-angled end in 50% of cases, the opposite - in 54.6%. The study of the obtained data and their subsequent discriminant analysis showed that the greatest intragroup correlation between the variables and the normalized canonical functions have such indicators as the difference between the blade length and the depth of the wound canal (0.628), the depth of the wound canal (0.544), sagging of the sharp end (0.445) and rib fracture (0.406). Other variables have lower correlation values \u200b\u200b(see table 4).

Table 4

Pooled within-group correlations between discriminant variables and normalized canonical discriminant functions

Based on the obtained coefficients, linear equations were drawn up taking into account the following indicators:
P - growth; Ok - precipitation of the sharp end of the wound; Op - siege of the opposite end; K is the length of the knife blade; G - the depth of the wound channel; P - the presence of a rib fracture.
To implement the problem of classifying cases and distribution in groups, we compiled equations using specific
coefficients and constants:

F1 \u003d P x 2.083 + Ok x 3.960 - Op x 4.371 + K x 0.102 + G x1.628 + P x 8.970 - 190.894

According to the results of the analysis, the predicted belonging to the first group is 95.5%, to the second 98.1%. It was found that 97.3% of the original grouped observations were classified correctly,
94.7% of cross-validated grouped observations are classified correctly.
To verify the data obtained, we carried out a discriminant analysis with the addition of data recorded during the application of experimental impact damage in comparison with previous studies. In this case, the same features were taken into account. Geometrically, a collection of objects belonging to the same class forms a region in space. The successful classification is evidenced by such signs as the concentration of cases belonging to the same class in one region of space and the minimal overlap of regions of other classes.

Fig. 7. Diagram of scattering of features, built on the basis of the results of discriminant analysis.

1 - experimental data; 2 - data from the acts of the ICI; 3 - experimental data obtained by impacts with a knife.

This figure shows that the experimental data obtained as a result of the fall of the body of the biomanikin on the knife blade (in Fig. 7 are presented in the form of markers with oblique shading) are located in the form of a cloud and are shifted to the right with respect to the zero mark. The data obtained during the study of the ICI acts (in Fig. 7 are shown by gray markers) form a denser cloud, mainly shifted to the left. The obtained values \u200b\u200bpractically do not mix. The results of experimental injuries received by impact with knives (in Fig. 7 are shown by black markers) are located in the data area of \u200b\u200bgroup 2, which indicates the same mechanism of their infliction and their difference from group 1.

FINDINGS

1. A technique has been developed for modeling stab and cut wounds of the chest when the human body falls onto a fixed knife blade using an original installation.
2. The investigated stab and cut wounds formed from the impact of a sharp weapon and experimental injuries caused when a person fell on a fixed knife blade revealed and confirmed evidence-based objective morphological signs for determining the mechanism of injury by sharp objects.
3. The data established as a result of the study made it possible to form a complex of differential diagnostic criteria (patent for invention No. 2308887 dated October 27, 2007). Stab and cut wounds resulting from a fall of a person on a fixed knife, in addition to the characteristics characteristic of this type of injury, have distinctive features: in the area of \u200b\u200bthe entrance wound, injuries characteristic of the complete immersion of the blade (abrasions from the action of parts of the blade or handle), depth the wound channel, if no bone structures are encountered along its course, exceeds the length of the blade of the injuring object by 4 cm or more; in the area of \u200b\u200bthe entrance stab-cut wound, straight (extensor) of one or several ribs, characteristic of the action of a blunt object, can form.
   The mathematical formula obtained as a result of statistical analysis can be used as an objective additional proof of an expert opinion.
4. An algorithm for the action of a forensic expert in the study of single stab and cut injuries in cases of a penetrating chest wound is proposed.

Based on the results obtained during the execution of the work, for forensic medical examinations related to solving the issue of the peculiarities of the mechanism of inflicting a single penetrating stab wound to the chest, the following recommendations were proposed for forensic experts.

1. The fall of a person onto a fixed knife blade from a height of at least 30 cm is always accompanied by complete immersion of the blade into the body, while in the area of \u200b\u200bthe entrance stab-cut wounds of the chest, concomitant injuries may occur. Under the impact of a sharp object, complete immersion of the knife is rarely observed and is often not accompanied by any changes in the edges and ends of the wound. Therefore, forensic medical experts, when conducting research on corpses with single stab and cut injuries of the chest, along with the traditional description of wounds, should pay attention to the following signs of a wound on the skin: the presence or absence of sedimentation of the skin around the sharp (blade) end, the presence or absence of sedimentation skin in the area of \u200b\u200bthe opposite (butt) end. The sedimentation of the skin around the acute-angled end, arising from the action of the beard or heel of the blade, can be of various shapes (rectangular, round, irregularly round or indefinite) and sizes, accompanied by deformation of the blade end. In cases of the action of the limiter or the end part of the handle, the abrasion of the skin in the region of the acute-angled end can be rectangular or indefinite in shape, correspond in size to this part of the knife or be somewhat smaller. The abrasion in the area of \u200b\u200bthe butt end may match the shape and dimensions of the handle stop or be slightly smaller. Thus, sedimentation in the area of \u200b\u200bthe acute-angled and opposite ends of the entrance stab-cut wound are morphological signs confirming the fall of a person on a fixed knife blade.

2. When conducting an internal examination, the depth of the wound channel should be carefully measured. It can be not only equal to the length of the knife blade used, but in cases of body falling onto a fixed knife blade, it can significantly exceed its length (by 4 cm or more). The wound canal in the end part can branch out as a result of repeated traumatic action of the knife blade due to the elasticity of the chest.

3. In the presence of damage to the bone skeleton of the chest in the area of \u200b\u200bthe entrance stab-cut wound, it is necessary to investigate their nature to establish the mechanism of damage formation. In the area of \u200b\u200bthe wound, there may be not only damage to the ribs and cartilage, typical for puncture or dissection with a knife blade upon impact. When a person falls on a fixed blade of a knife in the area of \u200b\u200bthe entrance injury, ruptures of the cartilaginous part of the ribs, fractures of one or more ribs, characteristic of the action of a solid object, can form.

4. When conducting examinations for single stab-cut wounds of the chest, where it is necessary to determine the features of the mechanism of its application in cases of a person falling with the front surface of the chest on a fixed knife blade, one of the additional methods the following formulas can be used to resolve this issue. The application of the formulas requires an examination of the knife that is supposed to be the weapon of injury.

In this case, the following data must be substituted into the formula: P - the height of the deceased person in cm; Ok - the presence of sedimentation of the blade end of the wound; Op - the presence of precipitation of the opposite end; K is the length of the knife blade (in cm); G - the depth of the wound channel (in cm); P - the presence of a fracture of the ribs (presence of a sign - 1, absence - 0).

F1 \u003d P x 2.083 + Ok x 3.960 - Op x 4.371 + K x 0.102 + G x 1.628 + P x 8.970 - 190.894

F2 \u003d P x 2.119 + Ok x 4.830 - Op x 3.956 + K x 0.668 + G x 0.468 + P x 3.492 - 186.292

5. Next, the obtained values \u200b\u200bof F1 and F2 are compared. If the F2 value obtained using the formula is greater than F1, then the investigated stab wound is most likely formed from a knife strike, and not as a result of an accident.

Thus, when conducting forensic medical examinations for single stab-cut wounds of the chest, the above formula can be used to resolve the issue of the mechanism of damage. In the presence of such signs as the prevalence of the depth of the wound channel over the length of the blade used as a crime weapon by 4 cm or more, the presence of sedimentation in the area of \u200b\u200bthe acute-angled and opposite ends, the presence of cartilage rupture or fractures of the ribs in the area of \u200b\u200bthe entrance wound, characteristic of the action of a blunt object (the end part of the handle or its limiter), we can confidently assume that a person fell by the front surface of the body onto the fixed blade of the knife.

1. Zakirov, T.R. Some morphological signs that allow us to judge the method of inflicting stab-cut wounds [Text] / T.R. Zakirov // Problems of expertise in medicine - Izhevsk: Expertise, 2006. - №4. - S.11-13.
2. Zakirov, T.R. On the possibility of establishing some conditions of injury in case of stab and cut injuries [Text] / T.R. Zakirov, V.A. Osminkin, S.A. Poilov // Modern possibilities of forensic examinations in the investigation of crimes: materials of the All-Russian Internet conference (April 20 - July 30, 2006). - Chelyabinsk: Chelyabinsk Law Institute of the Ministry of Internal Affairs of Russia, 2006. - 139 p.
3. Zakirov, T.R. Comparative analysis of signs of stab and cut wounds of the chest caused by various methods [Text] / T.R. Zakirov // Problems of expertise in medicine - Izhevsk: Expertise, 2007. - No. 2. - P.25-26.
4. Zakirov, T.R. Determination of the method of inflicting a stab-cut wound of the chest on the basis of an analysis of its characteristics [Text] / T.R. Zakirov // Actual problems of criminalistics and forensic examinations. - Sat. scientific. articles of the regional interdepartmental interuniversity scientific-practical conference dedicated to the 5th anniversary of the formation of the Department of Criminalistics, the 25th anniversary of the Izhevsk branch of the NA Ministry of Internal Affairs of Russia. - Izhevsk: "Expertise", 2007. - Issue 2, pp. 59-65.
5. Zakirov, T.R. Analysis of signs of stab and cut wounds according to medical and forensic research [Text] / T.R. Zakirov and V.I. Viter // Problems of expertise in medicine - Izhevsk: Expertise, 2008. - No. 1. - P.10-11.
6. Zakirov, T.R. Method for determining the features of applying a penetrating stab-cut wound of the chest // patent for invention No. 2308887 10/27/2007 Byull. No. 30

Stab and cut wounds - injuries associated with damage to the skin, with penetration foreign objects into the deeper layers. The characteristic features of such injuries are that they are inflicted mainly with sharp objects (a knife, pin, blade, debris with sharp edges), have the shape of an angle or a gap with even edges.

By the shape and depth of the wound, it is possible to identify the nature of the damage and approximately determine what kind of object it was inflicted. Knife wounds have a decent depth of penetration and a definite wound shape - pointed at one edge. A dagger strike leaves a wound with sharp edges on both sides. Blades and glass shards usually inflict superficial, sliding wounds with a shallow penetration depth and smooth edges. Penetration of an awl, a nail into soft tissue (puncture wound) leaves a small, round hole with a penetration depth that depends on the length of the object. Wounds can also be inflicted with ancient weapons such as a spear or sword. The nature of such wounds is very serious, the wound is often through, with very wide edges.

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You can read more about head injuries.

Features of the injury

Puncture wounds are generally considered less serious than wounds inflicted by wide, flat, sharp-edged objects. The severity of the injury is determined by its location, the depth of penetration, and the size of the wound. Moreover, a wound inflicted along the elastic fibers is considered less dangerous than penetration across the fiber, which leads to greater blood loss. Wounds inflicted in the area of \u200b\u200bthe heart muscle, liver, kidneys, spleen are considered especially severe and often incompatible with life. Penetration into hollow organs (lungs, intestines, stomach) is fraught with serious internal bleeding.But compared to gunshot and shrapnel wounds, stab wounds have an advantage in the absence of dead tissue around the entrance hole. This significantly reduces the risk of wound suppuration, but does not completely exclude it, for example, in case of intestinal damage, where there is a high likelihood of pathogenic microflora entering the general blood stream and its subsequent infection. In some cases, the item itself can be a source of infection.

First aid to the victim

The main task is to correctly assess the condition of the victim, the nature of the injury received, a thorough examination for additional damage and acceptance urgent action... Assessment of the victim's condition depends on the amount of blood lost and the degree of pain shock received. Necessary measures include stopping blood immediately and preventing possible wound infection. Since usually first aid measures have to be provided to people who are little knowledgeable in this area, it is necessary to take this matter with full responsibility. But in any case, if the victim's condition is serious, it is necessary to call emergency help.

With a deep wound and profuse bleeding, a tourniquet is applied to the limb above the lesion site. The tourniquet should not be applied for more than an hour and a half; every forty minutes it must be slightly loosened.

After that, the wound should be disinfected by first washing it with clean warm water. At the same time, hands should be ideally sterile; it is better to treat them with alcohol or potassium permanganate. Only after these manipulations are tissues processed. This can be done with hydrogen peroxide, potassium permanganate, medical alcohol or vodka.

In case of a serious wound that brings unbearable pain, it is recommended to make an intramuscular injection of analgin or baralgin.

Treatment of stab wounds

When treating wounds, they are divided into superficial, cutting wounds and deep wounds with penetration deep into the muscle tissue:

1. Superficial cut wounds. Superficial wounds caused by cutting objects are never sutured immediately, as an infection may remain in them, and reopening of the suture is possible. In this case, temporary stitches are used or the wound is not sutured at all.
2. Puncture wounds. It is mainly necessary to check the wound for the presence of foreign bodies, while taking into account that a small particle can be pushed out by the body on its own. But if the wound closes with it, then suppuration is possible. The puncture must be constantly washed with hydrogen peroxide and treated with antibiotics. If the injury is not serious, then it is quite possible to do with home treatment. Treatment of an injured foot requires increased attention, because pathogens that can cause gangrene enter the puncture from the ground. The leather on the sole is comparatively thick and it is difficult to expel dirt from the wound. Therefore, it is advisable to remove the upper corpus callosum of the skin before processing.
3. Deep wounds. During the first phase of healing, it is necessary to maintain the sterility of the wound by constantly flushing it with hydrogen peroxide. The edges should not be pulled together too quickly, the unclean contents must be completely pushed out, otherwise there is a risk of infection. The dressing should not be too tight and thick, otherwise the suction of fluids will begin.

In the second phase, when the risk of suppuration is behind, and the edges begin to tighten, it is necessary to help the regeneration process. Various ointments on any water-soluble base are excellent. Traditional medicine has many recipes for similar formulations.

Folk remedies

A very interesting old recipe

It is necessary to take one hundred grams of pine resin, lard, beeswax. If the resin is hardened, you must first grind it into powder. Put all the ingredients in a small container, melt and boil for 10-15 minutes, removing the formed foam from above. Cool, put in the refrigerator. Before putting a bandage with this mixture, the wound is washed with water and lime. A tablespoon of lime is slaked in a liter of water and left for several hours, after which it can be used.

The second recipe is no less effective.

Quicklime is poured into a glass up to half, poured to the brim with water, infused for 5-6 hours, after which the upper liquid is drained, leaving a thick sediment. You need to take an equal amount of vegetable oil, warm up for ten minutes, remove from heat, cool. Mix with the resulting lime residue, treat the wound with this mixture once a day, making a dressing on top.

Recipes for initial stage gangrene.

If the tissues around the wound have turned black, pain intensified, fever throughout the body, weakness, this is a sure sign of gangrene. In this case, it is necessary to cover the affected area with a cloth moistened with warm water. Inside it is necessary to take antibiotics, medicinal decoctions, a little alcohol will not hurt (not in combination with antibiotics). If it is not possible to hospitalize the victim, it is necessary to cauterize the wound.

Powders for external processing:

1. Coffee.
2. Charcoal.
3. Rubbed calamus rhizome of marsh calamus.
4. Any antibiotics (streptocyte, furacilin, etc.).

Several effective techniques

It is necessary to keep the affected limb very hot every day, so that only the leg endures, a strong solution of potassium permanganate for at least an hour, after which the surface is thoroughly dried and a breathable bandage is applied. There should be a noticeable improvement in two weeks.

Old medicine men advise to take some rye bread, coarse salt and chew it all thoroughly. Apply the resulting crumb to the gangrene in the form of a compress. It should be noted that the healing effect is achieved only in combination with human saliva.

To avoid injury, both accidental and deliberate, it is necessary to observe precautions at work and at home, to avoid unnecessary conflicts. Do not rely too much on self-healing, because even the smallest wound can lead to sad consequences, and there are many such examples. Late appeal for qualified assistance can result in disability or even death.