Forensic Handouts - Vikram Palimar Sir PDF

Mechanical Injuries Any harm whatever illegally caused, to a person in body, mind, reputation or property is an Injury (Section 44 IPC) Injury to any part of the body due to application of mechanical force is mechanical injury Classification Abrasion Contusion Laceration Bl...

Mechanical Injuries Any harm whatever illegally caused, to a person in body, mind, reputation or property is an Injury (Section 44 IPC) Injury to any part of the body due to application of mechanical force is mechanical injury Classification Abrasion Contusion Laceration Blunt force Incised wound Stab wound Sharp force Abrasion Abrasions are the injuries involving superficial layer of skin (epidermis) or - - mucous - membrane, due to impact against some hard, blunt or rough object/weapon - Features - Denudation of the superficial epithelial layer - Has only length and breadth (2 dimensions) - Bleeds less (since blood vessels are predominately present in dermis) - Heals without scar formation Types Scratch (Linear abrasion): caused by sliding movement of pointed objects like needles, thorns etc. Object causing scratch carries the torn superficial layers of skin producing heaping, which indicates the direction of force. - - Graze (brush burns): These are multiple linear abrasions produced due to tangential friction between skin and rough surface (dragging on the roads as in RTA). Epidermis gets heaped up at the opposite end indicating the direction of force. Pressure abrasion: When the force is perpendicular and of prolonged duration, epidermis gets crushed and the pattern of the object is replicated in the skin - surface (eg. ligature mark in hanging, strangulation) - Imprint abrasion: When the force is perpendicular and of momentary duration, the pattern of the object is replicated in the skin surface (eg. radiator grill mark in RTA, gravel particles) Both pressure and imprint abrasion are examples of patterned abrasions - Dr Vikram Palimar, Professor of Forensic Medicine, KMC, Manipal 1 Healing of an abrasion Fresh: Bright red 12- 24 hrs: Reddish Scab 2- 3 days: Reddish Brown Scab 4 –5 days: Dark brown scab 5-7 days: Brownish black Scab 7-10 days: Scabs falls off, leaving depigmented area (* - Scab consists of dried - - blood, lymph and epithelial debris) Medicolegal Importance Direction of injury: direction of force can be inferred based on heaping of epithelium (eg scratch, graze) Causative weapon: Produced by blunt force Pattern of injury helps to determine the causative weapon (eg. ligature mark in hanging, strangulation) Time since injury: based on the stages of healing of an abrasion Bruises (Contusions) infiltration of blood into the tissues following rupture of vessels as a result of application of blunt force Ectopic bruise (Migratory bruise): - Appearance of a contusion away from the site of trauma. - - Blood extravasation after trauma occurs along the lines of least resistance or by gravitation of blood in the empty tissue spaces - Examples include: - Peri orbital contusion (Black eye/ Raccoon’s eye/spectacle haematoma) seen in blow on the forehead - Thigh contusion due to trauma in pelvis - Ankle contusions due to trauma over the calf region. Delayed bruise: A deep bruise may take 1-2 days to appear - - This occurs due to haemolysis - of blood pigments and subsequent staining of tissues which result in delayed appearance of the bruise. - - Patterned contusion: Sometimes contusions replicate the pattern of the - weapon causing it. - Eg. Oval or circular bruises seen in manual strangulation - - - Six penny bruises over the trunk indicate child abuse - - Tram line (railway line) contusion seen in persons hit by a rod/stick. It is - - -- characterized by two --- parallel linear contusions with an unbruised area in between. This occurs due to yielding and stretching of skin underneath the - - - impact resulting in rupture of blood vessels on either side producing parallel - - - contusions. - Dr Vikram Palimar, Professor of Forensic Medicine, KMC, Manipal 2 Intra dermal bruise: situated in subepidermal layer. Pattern of the object is more - distinct. Eg. Tyre marks in road traffic accidents - - - - Factors modifying the appearance of bruise Site of injury: Loose and lax tissues like eyelids, genitals bruise more when compared to firm tissues like palms, soles etc - Vascularity of the part: Richly vascular areas like eyelids, genitals bruise more when compared to other areas for similar amount of force Age: Extremes of age bruise more - Children bruise more due to delicate tissues Elderly bruise more due to loss of flesh and weakened blood vessels due to hypertension and other changes (atherosclerosis) Sex: Women bruise more because of delicate tissues and greater amount of subcutaneous fat Colour of skin: Contusion more appreciable in fair skinned individuals Natural disease: Bruising is easy in person suffering from bleeding disorders, - leukemia, scurvy etc. - Colour changes in a bruise (Healing of a contusion) Fresh: Red (Haemoglobin) 1 day: Blue (deoxygenated haemoglobin) 2-4 days: Bluish black to brown (haemosiderin) 5-7 days: Green (Haemotoidin or billiverdin) 7-10 days: Yellow (billirubin) 14-15 days: Normal skin colour O This pattern of healing/colour changes is not seen in sub conjunctival - haemorrhage and meningeal haemorrhage possibly because of increased - - - oxygen - concentration in those tissues altering the breakdown of blood pigments. Features of Antemortem contusion Swelling of the tissues Epithelial damage Inflammation To differentiate contusion from lividity, washing with water after incising will help. - If blood gets washed off, then it is lividity since blood is in intravascular - - compartment. - If blood does not get washed off, then it is contusion since the blood is extra vascular and already has stained the tissues and does not get washed off. Dr Vikram Palimar, Professor of Forensic Medicine, KMC, Manipal 3 Medico legal aspects - Identification of object: Patterned bruising sometimes helps - Degree of violence: Contusions of vital organs like brain, heart etc even though - - over a small area can cause death. Contusions over non vital area may not cause death Cause of injury: Distribution of contusions indicate certain offences, for eg. Presence of contusion in inner aspect of thigh in a female indicates sexual - - - assault - Presence of contusion in the neck indicates manual strangulation (throttling) - - Six penny bruises over the trunk indicate child abuse - Time since injury: based on colour changes Artificial bruises: These are fabricated injuries produced by applying juice of irritants like marking nut, calotropis etc to put a false charge of assault on someone. It will be seen in accessible areas of the body. Vesicles (blisters) will be seen surrounding the injury. Characteristic colour changes will be absent. Lacerations These are the wounds in which the skin and underlying tissues are torn as a result of the application of blunt force. Features: - Edges are ragged, irregular and frequently bruised - Margins are commonly abraded - Deeper tissues are unevenly divided - Hair bulbs and blood vessels are crushed - Bridging of the tissues is seen Types: Split laceration (Incised-like or incised looking) - Skin gets compressed between the weapon and the overlying bone - Due to blunt perpendicular impact - Seen over scalp, face, shin, iliac crest etc - Has to be differentiated from an incised wound - Hand lens examination of the wound is helpful in such cases Stretch laceration - Produced due to over stretching of the skin beyond its elasticity till it splits and produces a flap - Eg. Pressure over the thigh can stretch the skin and produce a laceration in the inguinal region - Due to blunt tangential impact - Seen in Road traffic accidents Avulsion (Flaying injury) - Produced due to grinding compression of tissues - Avulsion of skin and sub cutaneous tissues from the underlying structures - Seen in run over accidents (Lorry, bus etc) Dr Vikram Palimar, Professor of Forensic Medicine, KMC, Manipal 4  Intermediata nation and - Tears - Produced by irregular sharp objects like broken glass pieces - Weapon in question not so sharp so as to cause an incised wound - Irregular tearing of skin and tissues Medico legal importance - Lacerations are commonly accidental or homicidal. Self inflicted lacerations are rare since they are painful - Foreign bodies/material present in the wound gives clue about the weapon used. Eg grease, dirt, mud etc may be seen in road traffic accidents - Direction of force may be concluded (in avulsion laceration) - Lacerations involving the vital organs like heart, brain, liver etc are fatal Incised wounds (Cut/Slash) Clean division of the skin and underlying tissues, caused by the slashing motion of a sharp edged instrument. Features: Margins: Clean cut, regular and well defined without bruising Everted Length: largest dimension Breadth: It shows maximum retraction of the edges at the centre. This is known as “gaping”. It depends on lines of Langer. Injury parallel to the lines of Langer show less gaping when compared to injury perpendicular to the lines of Langer. Depth and direction: Intially the wound is deeper and towards the terminal end it is shallower. This is known as tailing of the wound. It helps in estimating the direction of force Shape: Fusiform or spindle shaped Bleeding: Profuse haemorrhage is noted since the vessels are clean cut. Oblique strike: Produces an undermining of the edges. It helps in estimating the direction of force. Lacerated-looking incised wounds: These are the incised wounds seen in - those areas where the skin is wrinkled (eg scrotum, axilla). - - It looks like a laceration. - - Tissue bridging will be absent > point of differentiation - - - - Hand lens examination of the wound is helpful in such cases Hesitation cuts/Tentative cuts Self inflicted, superficial incised wounds seen in suicide Seen in throat, wrist Multiple wounds, superficial, non fatal wounds surrounding the main fatal wound Inflicted by the victim prior to the main fatal wound when he is hesitant to kill himself. Dr Vikram Palimar, Professor of Forensic Medicine, KMC, Manipal 5