WOUNDS
The human body is constantly subjected to mechanical forces during the course of life. The body usually absorbs such forces either by the resilience and elasticity of its soft tissues or the rigid strength of its skeletal framework.
If the intensity of the applied force exceeds the capability of the tissues to adapt or resist, a wound or injury occurs.
A wound means any solution or breach in the natural continuity of a tissue or organ caused by application of mechanical force to the body.
CLASSIFICATION OF WOUNDS
1- Legal classification: according to their results, time of treatment and punishment.
a) Slight or simple wound : which heals rapidly in less than 20 days leaving no deformity and no permanent infirmity.
b) Dangerous wound : which heals in more than 20 days and/or leaving a permanent infirmity.
c) Fatal or mortal wound : which cause death immediately or later due to complications.
2-Medicolegal classification: according to the instrument used.
a) Wounds inflicted by blunt instruments: as abrasions, contusions, contused and lacerated wound.
b) Wounds caused by sharp instruments as incised wounds and stab wound.
c) Firearm wounds.
d) Wounds caused by physical agents e.g.. burns (fire, hot liquid), electrical injuries and radiation injuries.
c) Chemical agents: e.g. strong acid and alkalis (corrosives).
HOW A WOUND IS PRODUCED
The mechanical force causing a wound maybe caused by:
1-A moving instrument or object (force) on a stationary body (counter force).
2-By movement of the body itself (force) on a stationary ground (counter force) e.g. in falls.
As a result of impact between the force and the counter force, an energy is produced which can displace or deform (change the shape) of the affected tissues e.g. the rigid tissues like the bones undergo fractures, soft tissues may change their shape, or if the force is more than their tensile strength they rupture and wounds are produced.
FACTORS INFLUENCING THE TYPES AND EXTENT OF WOUNDS:
I. Instrument used:
a. Type of instrument used: whether blunt, sharp or firearm weapon.
b-Size of the striking surface area of the instrument .
- Small surface area e.g. screw driver—> Small localized wound.
- Large surface area — large size wound.
c. Shape of the striking surface area of the instrument usually a wound takes the shape of the causal instrument.
d. Material from which instrument used made:
Instruments made of a wooden or plastic material — less damage than a rigid instrument, because part of the energy is used in deforming or breaking the instrument.
2- Amount of energy produced during the impact
This is measured by the formula £ =1/2 mv2 where m= mass or weight of instrument, v = velocity of instrument. The velocity of the instrument is more important than the weight because:
If the weight of the instrument doubled, the kinetic energy doubled,
If the velocity of the instrument doubled, the kinetic energy
quadrupled
3- State of the body at the time of impact
If the body or part of the body affected by the impact is free to move e.g. a blow to the head which is free to move may cause less damage (because part of the force is absorbed in moving the head), but a similar force or blow to a resting head (supported) may cause marked damage.
4- Nature of the affected tissue
a) Skin: is very pliable and somewhat elastic, so if blunt instrument is applied to the skin, no damage but the underlying structures may be severely damaged (bruises). Although the skin may split when crushed against rigid bone. (E.g. skull, chin of tibia, eye brow).
b) Subcutaneous tissues: a blunt force applied —> subcutaneous bruises (due to presence of fat and fragile connective tissue).
c) Muscles: Muscles may be crushed, torn or lacerated (by fragments of broken bone) or ruptured if unduly stretched.
d) Bones: Bones are rigid so they may either bend without fracture especially in children e.g. ribs, or fractured if the force is more than the limits of its elasticity.
e) Body fluids and gases:
- Fluids: are incompressible, so it may be displaced by forces which lead to rupture of anatomically distant and weak tissues e.g. sudden compression of the chest as in traumatic asphyxia (fall of buildings) may cause displacement of blood in the great thoracic veins —÷ rupture of the distal venules and capillaries producing petechial hemorrhages .
Types of wounds
•Abrasion :-
•An abrasion is a type of wound in which the skin is scraped or rubbed off.
•Pure abrasion does not bleed .
•Abrasions are usually superficial wounds .
There are many types of abrasions:-
Brush abrasion (childhood falls )
Patterned abrasion indicates the nature of the weapon (nail marker , bite marker )
IMPRESSION OR IMPACT ABRASIONS
- It is caused by stamping of some object against the skin .for a short
- time. These are called patterned abrasion i.e. they keep the pattern of the impacting object.
1- Longitudinal or linear scratches: caused by dragging of finger nails across the skin, it has a broad commencement.
- Semi lunar or crescent scratches: when nails dug into the skin, if the thumb inflict the injury --- semi lunar scratches plus small ecchymosis.
- Triangular scratches: if nails were pointed.
- Small cuts if finger nails were long.
2- GRAZES = Brush abrasions
They are multiple parallel linear scratches. It occurs when a broader surface of the skin comes iii contact with a rough object.
If friction occurs on a rough surface e.g. gravel —coarse graze with particles in the wound, if friction occurs on a smooth surface e.g. asphalt --fine graze. The direction indicated by a clean commencement with tags at the end. Variation in depth occurs in different parts. Grazes caused by fall on the ground are found usually over the prominence of elbow, front of the knees and hands
3-IMPRESSION OR IMPACT ABRASIONS
It is caused by stamping of some object against the skin .for a short
time, e.g. impact abrasions caused by the radiator of car, tyre marks, and steering wheel abrasions. These are called patterned abrasion i.e. they keep the pattern of the impacting object.
4- PRESSURE ABRASIONS
It is caused by a linear pressure on the skin plus movement commonly seen in hanging or strangulation caused by the rope.
5- BITE ABRASIONS
Human bite abrasions are elliptical in shape, Present mainly in the upper Part of the body. Human bite may be inflicted upon the victim e.g. in rape or upon the assailant in self defense or on the body of a child in child abuse. Animal bites usually present in the lower half of the body especially in the lower limbs, it is in the form of two Parallel rows with prominence of the canine. Human marks may be found on food stuff e.g. cheese, buffer, chocolate or on human tissue.
Bite marks can be photographed soon as possible before changes in the tissues or by ink impregnation and compared with that of the suspect as regards irregularities, size of teeth, spacing, arrangement, missing of some teeth .etc
So, the suspect could be identified from the characteristics of teeth as well from DNA typing of the saliva left at the site of bite.
Medicolegal importance of abrasions:
1-It may be the only evidence of a crime or violence be. signs of resistance.
2- It can give an idea about the type of the crime from its site. e.g
- Finger nail abrasions around the mouth and nostrils means smothering.
- Finger nail abrasions on the sides of the neck means throttling (manual strangulation).
- Finger nail abrasions on the inner side of the thighs means rape.
- Rope mark on the neck means strangulation or hanging.
3- It can give an idea about the instrument used from its shape e.g. finger nails, radiator of motor car, rope mark.
4- Differentiate incised and contused wounds.
5- The age of abrasion gives an idea about the date of the crime. First it is reddish, tender, oozing serosanguinous for a day or two. On the 3rd day it is covered with Gradually the scab dries up and become dark brown. Fallen of the dry scab occurred from 7-10 days leaving a red colored area. Disappearance of the abrasion occurred in three weeks and this depends on the width and depth of the abrasion.
6- Ante mortem and postmortem abrasion
Ante mortem abrasions / Postmortem abrasiona-Reddish, swollen / a-Yellow, translucent.
b- May be accompanied by bruises / b-No bruises
c-On microscopic exam. ----vital tissue reaction. / c-On microscopic exam.----No vital tissue reaction
d-Some remnants of the damaged epithelium. / d-Devitalized epithelium
e-Occur anywhere / Usually on prominence.
Vital tissue reaction:
a. Inflammatory response:
Revealed microscopically within 1-6 hours
b Histochemical changes:
- Decrease in enzyme activity: in the zone adjacent to the wound
- Increase in enzyme activity: in the periphery.
c. Biochemical changes:
- Increase in serotonin and histamine levels.
7- Abrasions must be distinguished from
a. Post mortem injures caused by ants or insects (usually are found at mucocutaneous junctions e.g. angles of mouth, eyelids, margins of nose.
b. Excoriation of the skin by excreta seen in infants.
c. Pressure sores.
Danger of abrasions:
I. Tetanus 2. Erysipelas
CONTUSIONS = BRUISES كدمات
DEFINITION
Extravasations of blood in the tissues following rupture of blood vessels as a result of application of blunt force. It varies in size from a small pin head ecchymosis to a large collection of blood, known as hematoma.
SITE
1-Subcutaneous tissue —> subcutaneous hematoma.
2-In the deep organs e.g. brain contusion, cardiac contusion, lung contusion.. etc.
SIZES
The size of a bruise depends mainly on the amount of force, part injured, delicacy of tissue, condition of arteries and sex of patient.
SHAPE
Usually it takes the shape of the causal instrument e.g. small rounded bruises caused by fingertips, closed fist and the end of stick. An elongated bruise caused by a stick. A bruise in the form of two thin parallel lines produced by a whip or a pliable stick, it may be curved and partially encircle the body.
SITE:
The site of a bruise does not usually indicate the site of violence. The position of a bruise may show the manner of assault e.g. when the arms are grasped by the hands there may be 3 or 4 bruises on one aspect (caused by the fingers) and one larger bruise opposite (caused by the thumb) indicating the position of the assailant in front or behind the victim.
AGE
The age of a bruise usually depends on its size and depth. The color of a bruise is first bright red (oxy HB) —> violet, then bluish color (reduced HB) —> green colour (biliverdin) —> yellow color (bilirubin) and gradually disappears in 15 days (range from 2-4 weeks). The color changes occur from the periphery inwards.
Generally the size, site and shape of a bruise depend on:
I. The amount of violence applied to the body.
2-The instrument used.
3-The condition and type of tissues.
Bruises are more easily and extensive in loose and lax tissue e.g. eyelids and in tissues with excessive subcutaneous fat. On the other hand, bruises are Tess and even absent in tissues strongly supported by fibrous tissues e.g. scalp, palms and soles, also in persons with good muscle tone e.g. in boxers.
4-Texture and colour of the skin: Bruises are more apparent in fair people than dark people.
5- Age: Children and old peoples tend to bruise easily, In the former it is due
to looseness and delicacy of skin as well the presence of subcutaneous fat. While in the latter it is due to loss of flesh and subcutaneous fat, as well vascular changes in the form of atherosclerosis.
6- Sex: Women bruised more easily than men due to delicacy of tissues and presence of subcutaneous fat especially if obese.
7- Certain diseases: Patients suffering from hypertension, cardiovascular degenerative changes, purpura, hemophilia, leukemia and survey are more easily bruised.
8- Gravity: bruises can appear at places away from the site of violence e.g. a blow on the forehead -+ bruise round the eye, a blow on the abdomen
-bruise in the scrotum.
ANTEMORTEM OR POSTMORTEM BRUISE
The production of postmortem bruise is possible, within 2 hours after death, but requires severe violence, and the resulting bruise is usually, small in size. Antemortem bruise is tender, with swelling of the tissues, discoloration of the skin, infiltration of tissues with blood and cellular infiltration.
DANGER OF A BRUISE:
1- Neurogenic shock: due to reflex vagal inhibition of the heart especially in areas rich in parasympathetic supply e.g. mastoid, neck, pericardiurn, epigastria, hypogastria and genitalia.
2-Injury to internal organs.
3. Liability to sepsis and death from septicemia.
DIFFERENTIATION BETWEEN 1IYPOSTASIS AND BRUISES:
Hypostasis / Bruise1-A postmortem change / I. Occur in the living
2. Site: dependent parts / 2. Anywhere
3. Skin: intact / 3. Accompanied by abrasions
4. No swelling, no color changes / 4. There is swelling, color change
and no marked edges. / and well marked edges.
5. By pressure the color / 5. By pressure the color dose not
disappear / disappear.
6. The blood is intravascular / 6. The blood is extra vascular not
washable and fluidly. / washable and clotted.
7. No cellular infiltration. / 7. There is cellular infiltration
MEDICOLEGAL IMPORTANCE OF A BRUISE:
1-May be the only evidence of crime or Violence.
2-May be the only evidence of signs of resistance.
3-The date of the. crime can be estimated from it age..
4-Give an idea about the instrument used (from its shape).
5-Differentiate between incised and contused wound.
6- May be the cause of death.
7- It should be differentiated from hypostasis.
CONTUSED WOUNDالجرح الرضي
Definition:
An open injury produced by the impact of blunt force against the body. It is caused by a stick, stone, or fall from a height. The edges are usually abraded with contusions around, and the angles may be multiple and irregular.
Classification:
According to the way by which they are produced:
1-Contused wound: When there is crushing of the skin between two hard objects e.g. scalp, chin of tibia, cut eye brow of the boxer. (Here contused wound may simulate cut wound ).
2-Laceration: جرح رضى متهتك it is a contused wound where the edges are
severely damaged an highly irregular, with multiple angles. The
appearance of the laceration may not accurately reflect the instrument that
produces it. One can have lacerations of internal organs as well as skin.
3- Crush injury: When a heavy blunt mobile instrument runs over a limb or a body e.g. runs over by a motor car.
4- Torn wound: Caused by belts of machines ----- tearing of the whole limb and we called it tearing injury or torn wound, here the tissues are twisted (skin, muscles(.
5- Cut laceration: inflicted by heavy sharp cutting instrument e.g. by the blade of axe.
Medico legal importance of contused wound:
I. it indicates the type of injury and causal instrument.
2-Could simulate incised wound in the skin stretched over bone e.g. scalp.
3-If in the head it may accompanied by fracture
Danger of contused Wounds:
1-Liability to sepsis.
2-Neurogenic shock.
3-Crush syndrome. MyoglobinuriaRenal failure.
4-Fat embolism (fracture of long bones(.
5- On heating a scar is produced . may leave permanent infirmity.
INCISED WOUND (CUT WOUND)الجرح القطعى
Definition:
It is produced by drawing the edge of a sharp instrument along the
surface of the skin with sufficient pressure e.g. of sharp instrument, knife. razor. and broken glass.
The wound is. usually more long than deep, having clearly cut sharp edges and base. in some cases the edges are irregular and ragged which may be due to overlapping by multiple incisions, or may. be due to corrugation and looseness of the skin at the site of injury e.g. neck, axilla and scrotum, (here cut wound may simulate contused wound(.
The edges of the wound are usually gaping due to the elasticity of the skin and cuffing of the underlying muscles especially if the muscles are cut transversely. External bleeding is usually free, sepsis is less and usually the wound heals by first intention.
Shape of the wound
It is usually linear, but it may be curved or V shaped if the direction of the weapon is changed during infliction of the wound.
The cuts in the clothes do not always coincide with the wound especially when clothes are loose.
Therapeutic incised wound:
Following surgical interference e.g. for exploration.
Differentiation between homicidal, suicidal and accidental cut wounds:
Homicidal / SuicidalArranged
Vulnerable sites
(neck, groin,
wrist) / Accidental
1. Characters
2. Site / Irregular
Accessible
& vulnerable
(face, neck) / Arranged Vulnerable sites (neck, groin, wrist) / Irregular Any part
.
.
3. Number / Multiple / Multiple parallel / Usually single
4. Clothes / May be involved / Not involved / May be involved
5. Defense wounds / May be present
. / Absent / Absent
Medicolegal importance of incised wound
1-It indicates the type of instrument used.
2-Its site indicates the type of crime whether homicidal or suicidal.
3-Could simulate contused wound.
Danger of incised wound
1-Severe bleeding.
2- Cutting of important nerves and tendons.
3- Air embolism.
4. Infection.
Differentiation between Cut and Contused Wounds
Cut wound / Contused wound1. Instrument / Sharp cutting / Heavy blunt
2.Edges . / Sharp regular, except in wounds in corrugated areas
Acute / Ragged, irregular, with contusions and abrasions around
3-Angles / Acute / Irregular
4, Base / Sharp / Irregular
5. Bridging / Not present / Present
6. Gaping / Present / Absent
7. Bleeding / Free external bleeding
— / Less bleeding
8. Blood vessels . / Sharply cut / Incompletely torn
.
9. Hair / Sharply cut ends / Brushed, irregular ends
10. Sepsis / Less . / More
11-Healing / By first intension with minimum scar formation / By secondary intension leaving permanent scar
STAB WOUNDالجرح الطعنى
A wound caused by thrusting or forcing sharp pointed instrument into the body, having a sharp edged blade e.g. knife, scissors.
Punctured Wound: Caused by thrusting an instrument with a blunt edge and pointed end e.g. nail.
Penetrating Wound: These are stab or punctured wounds reaching a body cavity e.g. chest (pleura, pericardium), abdomen (peritoneum), joint cavity.
Transfixing Wound =Perforating Wound: These are stab or punctured wounds transfixing a limb or even the whole body.
Characters of Stab Wound:
1-Is usually more deep than long.
2-Its depth being usually relative to the length of the blade.
3-The width is also relative to the breadth of the blade, sometimes the wound may be enlarged on withdrawing the instrument.