بسم الله الرحمن الرحيم

Wounds

Objectives 1- To know the definition and classification of wounds. 2-To know the type of trauma and wounds of medicolegal importance. 3- To know the physical and biological factors affecting the wound. 4-To be able to estimate the date of wound occurrence. 5- to know the different types of wounds. 6- To know the complications of wounds.

Definition of Wound Disruption of the continuity of tissues produced by external mechanical force. Or may be defined as(legal definition): Breach of the full thickness of the skin (or lining of lip). This excludes abrasions, bruises, internal injuries and fractures.

INJURY: from the latin injuria (in- not, jus- the law)  INJURY: from the latin injuria (in- not, jus- the law). The term is often used synonymously with wound but can have a wider use, including damage to tissues by heat, cold, chemicals, electricity, radiation, in addition to mechanical force.

LESION: from the latin laesio (a hurt) LESION: from the latin laesio (a hurt). Originally meant injury, now more widely applied to include '' any area of injury, disease or local degeneration in a tissue causing a change in its function or structure''

TRAUMA :- bodily harm with or without structural alterations resulting from interaction with physicochemical agents, imparting energy to tissues. May cause morphologically apparent damage (wound) or produce physiological imbalance (eg reflex cardiac arrest by neural stimulation) and secondary effects (eg thrombosis, infection, obstruction of tubular organs.

Factors affecting trauma A- Mechanical factors: 1) Mechanical Force Blunt force trauma (BFT) -A moving object (KE) striking the body as in a blow -The moving body (KE) striking a fixed object or surface as in a fall causes bruises, abrasions and lacerations

1-Mechanical force It may cause:- Impact, Angulation, Compression, Traction, Torsion, Shearing, Acceleration/deceleration. Different tissues have varying properties of Elasticity (tendency of stressed material to regain its unstressed condition .

Different tissues therefore have different elastic limits (tolerance limits or break points) and are vulnerable to different stresses. Skin has greater elastic limit than underlying fat and blood vessels making subcutaneous bruising more common than skin laceration. e.g. torsion often causes spiral fracture of tibia, soft tissues undamaged.

Compression often causes rupture of gas-filled lung or intestine, but muscle and skin undamaged. Injury occurs when energy applied exceeds the elastic limits (or tolerance) of the tissues.

2) Sharp force: knife tip or edge, broken glass, jagged metal - applied force is concentrated over a small area, requires little force to cut tissues 3) Firearm; high velocity, small mass projectile

4) Thermal energy: heat or cold 4) Thermal energy: heat or cold . 5) Electrical energy: flow of current may cause localized burn if resistance is high. 6)Atmospheric Pressure: high or low, in air or water. 7) Radiation: particle or radiation . 8) Chemical reaction with tissue releasing energy.

2-Physical factors 1) Degree of Force or K.E. applied: Force = Mass x Acceleration Kinetic Energy = 1/2 Mass x Velocity2 Energy depends on mass of weapon or projectile, but on the square of its velocity

2) Area over which force is applied: If the same force spread over larger area is less likely to injure at site of impact edge or tip of knife allows a great concentration of force applied.

3) Duration over which force is applied: longer duration allows tissues at site of impact to deform and dissipate the applied. 4)Energy e.g fall onto soft surface (increases duration and area of impact). seat belt stretching slows down the rate of transfer of kinetic energy to the body and spreads the area of impact over the trunk.

4) Direction of application:  Transfer of kinetic energy from weapon or projectile is incomplete with a glancing blow or exiting bullet (some wounding potential is wasted) and complete when the weapon or bullet come to rest on/in the body.

3-Biological factors 1) Mobility of the body part Fixed parts absorbs all applied energy. Mobile parts are able to transform KE into movement 2) Anticipation and coordination e.g.-boxer rolling with a punch spreads out the duration of impact, catching a cricket ball, rolling with a fall

3) Biomechanical properties of tissue Different tissues have different strengths and weaknesses -skin is elastic and more resistant than underlying tissues (Bruise > Laceration) -blood vessels more resistant to compression than stretching -hollow or fluid-filled organs sensitive to compression -

brain (semi-fluid) more resistant to direct impact than rotational impact (--> shearing of nerve fibres) -bone and joint may transmit force to a weak point

Classification of wounds Legal classification: A- Slight or simple wound جـرح بسيط: which heals rapidly in less than 20 days leaving no deformity and no permanent infirmity. B- Dangerous wound جـرح خطير : which heals in more than 20 days and/or leaving a permanent infirmity.

C- Fatal or mortal wound جـرح مميت : which cause death immediately or later due to complications.

Another classification:- Abrasions, Contusions, Cut wounds, Contused wounds, Stab wounds Firearm wounds.

1-Abrasions Definition:- Destruction of the superficial layers of the skin following contact with rough object. Bleeding is minimum, it heals rapidly in few days. Abrasions are usually localized at the site of trauma. Forms:- Tangential, crush, finger nail,or patterned abrasions .

Medicolegal importance 1.It may be the only evidence of a crime . 2. 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 . Finger nail abrasions on the inner side of the thighs means rape. Rope mark on the neck means strangulation or hanging.

The instrument used from its shape e.g. finger nails, rope mark. 4.Differentiate incised and contused wounds. 5.The age of abrasion gives an idea about the date of the crime: It is reddish, tender, oozing serosanguinous for a day or two.

On the 3rd day, it is covered with brown red soft scab. 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.

6.Ante mortem and Postmortem abrasions Antemortem abrasions: A-Reddish, swollen. B-May be accompanied by bruises C- On microscopic exam.  Vital tissue reaction. D- Some remnants of the damaged epithelium. E- Occur anywhere

Postmortem abrasions: A-Yellow, translucent. B- No bruises Postmortem abrasions: A-Yellow, translucent. B- No bruises. C- On microscopic exam. No vital tissue reaction. D- Devitalized epithelium. E- Usually on prominence

2-Contusions or burises 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

The color of a bruise is first bright red (oxy HB)  violet, then  bluish (reduced HB)  green (biliverdin)  yellow (bilirubin) It gradually disappears in 15 days (range from 2-4 weeks). The color changes occur from the periphery inwards.

Danger of the bruises 1. Neurogenic shock. 2. Injury to internal organs and hematoma. 3. Liability to sepsis and death from septicemia.

Medicolegal importance of the bruises 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 its 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

DIFFERENTIATION BETWEEN HYPOSTASIS AND BRUISES 1. Occur in the living. 2. Anywhere . 3. Accompanied by abrasions. 4. There is swelling, color change and well marked edges. 5. By pressure the color dose not disappear. 6. The blood is extravascular and clotted. 7. There is cellular infiltration

Hypostasis: 1. A postmortem change. 2. Site: dependent parts. 3 Hypostasis: 1. A postmortem change. 2. Site: dependent parts. 3. Intact Skin. 4. No swelling, no color changes and no marked edges. 5. By pressure the color disappear. 6.The blood is intravascular, and fluidly. 7. No cellular infiltration

3- Contused wound 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.

4-Lacerated wound Definition It is a contused wound where the edges are severely damaged and highly irregular, with multiple angles.

Medicolegal importance of contused wound 1.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 wound 1.Liability to sepsis. 2.Neurogenic shock. 3.Crush syndrome. Myoglobinuria  Renal failure. 4.Fat embolism (fracture of long bones). 5.On healing a scar is produced  may leave permanent infirmity.

6-Incised wound (cut wound) 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.

Danger of incised wound 1. Severe bleeding. 2. Cutting of important nerves and tendons. 3. Air embolism. 4. Infection

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.

7- Stab wound Definition 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 eg: 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. More deep than long. 2. The edges : are cleanly cut without surrounding abrasions or contusions. 3. The shape: - Bibladed knife(double dladed)  Two pointed sharp angle. - Monobladed knife(single bladed)  One end is sharp pointed, the other is transverse

Danger of stab wound 2. Injury to vital organs. 1. Neurogenic shock. 2. Injury to vital organs. 3. Internal hemorrhage. 4. Sepsis.

DEFENSE WOUNDS = SELF PROTECTION WOUNDS These results from the victim's spontaneous reaction of self protection when he is attacked. He may either grasp the weapon to prevent it injuring a vital part, or may raise his arm or hand to ward off an attack.

Fabricated wound They are usually done by the person himself (self inflicted wounds) to give suspicious of self defense or by the aid of another person in agreement with him. They are usually superficial, consists of a series of parallel or crossing incisions.

Commonly seen over accessible parts e. g Commonly seen over accessible parts e.g. top of the head, forehead, neck, front of chest or abdomen. Usually there is no corresponding cuts on the clothes.

Causes of death from wound I. TRAUMATIC SHOCK A. Primary or neurogenic shock: i. Death from reflex vagal inhibition of the heart i.e. parasypathetic stimulation  slowing of the heart  instantaneous death. ii. Death from sympathetic stimulation of the cardiovascular system .

B-Secondary or hemorrhagic shock II. HEMORRHAGE: Types of hemorrhage: 1. Primary hemorrhage follow immediately after injury. 2. Reactionary hemorrhage is usually delayed for several hours up to 24 hours after injury. 3. Secondary hemorrhage is due to infection of a wound, it occurs between 10-16 days after injury

III. INFECTION OF THE WOUND. IV. EMBOLISM: A. Air embolism The minimum amount of air to cause air embolism is 60 ml. B. Pulmonary embolism due to deep vein thrombosis. C. Fat embolism.

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