foreign [Music] my name is Dr Shilpa Singh I'm a postgraduate in forensic medicine from Armed Forces Medical College Puna today the topic that we'll be talking about is mechanical injuries so diving right ahead into the topic let's start first with abrasion now what is abrasion abrasion is basically just a superficial denardation of the skin or the mucous membrane it is a two-dimensional injury what I mean by a 2d injury is that it only has length and breadth it does not have a depth it's a two dimensional injury Only The Superficial denardation of the skin is taking place there are various types of abrasion which we will discuss once it comes across number one is scratch or linear vibration very simple to understand it happens with any of the pointed objects with a small surface like a needle a thorn a gray sliding scrape or grinding these are various terminologies for the same type of abrasion where the same type of force is causing uh this type of abrasion most commonly encountered in road traffic accidents where there is dragging on a broad rough surface so that causes a Grace a sliding a scrape or a grinding abrasion moving ahead a pressure abrasion or a crushing friction Force abrasion is one that is generally found in questions in cases of ligature Mark in hanging or strangulation where there is pressure or there is crushing of the underlying tissues imprint abrasion also known as impact abrasion contact or patent there's a slight difference between impact and contact we'll discuss it in the upcoming slides but for now any imprint abrasion is one which can be caused by a printed rough object like a radial Grille a headlamp Rim a teeth and bite marks they are also known as imprint abrasions now the mechanism of vibration decides the type of abrasion what happens is if there is a tangential force it can cause a linear abrasion or a Grace abrasion like we discussed graced abrasion most commonly encountered in road traffic accidents linear ones whether with the needle with a thorn these were the ones that we've discussed it can be a pointed object with a small surface compression force now this can cause a patent as well as a non-patent impression in pattern we've discussed about impact or contact like radiator grilles headlamps rims of a motor vehicle and also teeth or bite marks now these are a few photographs who depict an abrasion correctly like we discussed it's a two-dimensional injury where there is only length and breadth and no depth to the injury gravel rash Road Rash or brush burns like we discussed there is heaping of tissue at one end it is because of a coming in contact with a rough and a broad surface so Grace abrasion or brush one discuss grinding sliding or brush Burns why do we call it brush Burns we'll discuss again most common type as we have said earlier it's because of the road traffic accident now the question that I was talking about why are we calling it brush Burns basically it mimics an injury of burn it occurs when the skin is rubbed or there is some friction against a rough surface that commonly happens in road traffic accidents uneven longitudinal lines of abrasion are seen if I can go back to the previous slide this is what I would it is uneven parallel longitudinal lines epithelium is heaped up at the end of these lines which indicates the direction of force now this is important for medical legal importance that the heaping of tissue at one end of the injury it indicates the force from where which the pressure has been applied Suppose there is heaping of here tissues this is the injury so the force is here this is how the injury must have taken place pressure also known as crushing abrasion or because of friction over here we can see this is a picture in which sustained pressure of a rough object or it could be at 90 degrees has caused the crushing of The Superficial layers of the skin and hence there is an abrasion present ah there is no force on impact but because of the sustained pressure after the object comes in contact with the body surface so basically there has been no force that has been directly applied to this injury what has happened because of sustained pressure at 90 degree a pressure or a crushing abrasion has occurred timing of vibration now this is a most commonly asked question what is the timing of abrasion and what do we mean by timing of vibration basically abrasion is an injury which will heal very rapidly it causes minimum bleeding and it generally heals in a less than a week with no permanent disfiguration no permanent scap formation so that is the quality of an abrasive injury but this Focus cap formation might not be permanent still it indicates the time duration or the time interval since the injury has taken place this is of medical legal importance to correlate the time effort to the timing of abrasion so if it is bright red without scap definitely it's a fresh injury there is always minimal bleeding in abrasion it doesn't bleed much reddish scab is present it can be somewhere around 12 to 24 hours like half a day to one day if there is a reddish Browns cap present the injury timing indicates the time interval is of two to three days a dark Brown's Cab is generally four to five days brownish cab is five to seven days the scab has fallen off and there is a denuded or a depigmented area lying underneath so it is 7 to 10 days that is the time interval since the injury has taken place this table is important for a variety of reasons that we need to mug up these points it can be asked that when is the the question that can be most commonly asked is when is the scab reddish brown after how many days of Entry or if the scab has fallen off and the underlying the pigmented area is being seen then please tell us the time interval of the injury that must have occurred so these can be various questions on the timing of abrasion it's a very simple table to learn also now the medical legal importance of vibration why do we need to know like we discussed direction of injury based on the heaping of tissues wherever the injury direction will take place there will be heaping of tissues with underlying denuded or underlying area which is comparatively lighter in color because of the denotation of the skin so the direction of injury the most common one the most asked one positive weapon yes like we discussed if there is a pattern to it we can always talk about the causative weapon like in a radiator Grille a headlight rims teeth and bite marks there's a pattern to it so the offending weapon can be correlated to it times in surgery the table that we discussed just a slide back that will tell us the time interval of Entry place of occurrence this can also be very important especially in road traffic accidents it can the abrasive injury might have a little bits of particles of dirt gravel or glass particles attached to it so that can also give a clue as to the place of occurrence of that particular injury in road traffic accidents most commonly doesn't rule out all the other aspects but most commonly in road traffic accidents moving ahead artifact celebration this question has been asked a lot what are post-mortem artifacts will come to a completely separate topic known as postmortem artifacts but right now we are only talking about the artifacts in abrasion what do these artifacts lead us to believe basically if something is mimicking an abrasion injury or an abrasion that will cause a misdiagnosis or a subjective error in a case of medical legal importance so we need to know the difference between the artifacts that are produced by ants by insects by Animals by marine animals by excoriation of skin due to excreta or bad Source these will look very different or they might look a little similar to an abrasion injury and hence cause us to believe that it is a true abrasion where it is not so so we need to keep our eyes open for any artifacts in diagnosing an abrasion entry anti-modum versus postmortem abrasion uh most commonly antimotom abrasions can be located anywhere on the body it can be because of the Fall it can be because of other reasons but postmortem abrasions are generally on bony prominences when the body is being dragged or the body is being changed into positions or something of that sort the color of healing will depend on the stage of healing it can be bright red it can be reddish then it can be reddish brown that it can be brown and then it can be a scap with a denuded skin so it can indicate the stage of feeling but it is always this is the question it is yellow translucent and parchment diced in a case of postmortem abrasion there is no redness attached to it there is no healing process to it exudate obviously there will be more exudate because it's a life process vital reaction will be present scalp formation will be present and all these three will be absent in a case of postmortem artifact it is because generally because of the handling of body post death generally which causes a postmodern abrasion so it is very easy to differentiate between antimotom as well as a postmortem abrasion so moving ahead with confusion uh what happens in contusion is it is also known by the name of Bruce they can be extravization of blood in the subcutaneous or the submucous tissue due to the rupture of capillaries there is no breach and continuity of the covering skin so what was happening in abrasion was the covering skin was being dragged or it was being denuded or the epithelium or was being heaped up at one end of the injury but in a bruise in a contusion there is no breach in the continuity of the covering skin there is only extravision this is the covering skin there is extravization of blood uh in the subcutaneous or in the submucous tissue due to the rupture of capillaries so various capillaries have ruptured this Skin Integrity is present and this has caused a contusion or a bruise the factors there can be many factors which modify the appearance of a bruise the site of Entry it might two different sites in the body may give an appearance that there are different types of contusion while it might have been because of the same weapon at the exact same time to the same person but different parts of the body vascularity of the part yes because it is of the underlying reason is rupture of capillaries which leads to bruising so definitely if the vascularity of that particular body part is high we will have a lot of bleeding under the skin age older and infants at both the spectrums of age that is children and old people at both the ends of the spectrum contusion of bruising is more common in children we can assume because the skin and the epithelium is very soft and old people because of the luxury of the skin sex It generally uh females bruise easier than males it is said so color of the skin uh White skinned I'm sorry to use that term but it is what it is a white skin or a lighter skin to be more honest a lighter-skinned individual will show a bruise more appropriately as compared to a person of a darker color some natural diseases especially liver diseases in which bruising is very common so it also indicates some kind of an underlying disease so these are the various factors that modify or that alter the appearance of a bruise a patent or a different types of bruising most common are patterned rules this is basically intradermal bruise where the weapon sinks into the skin with little or no damage to blood vessels Over The Ridges I'll explain it well with a diagram the traction that causes marginal blood vessel to rupture in the skin forced into the grooves so bleeding is into the skin is minimal and hence there is no or little damage to blood vessels over the riches how does this happen for example in cases of spherical objects in cases with balls if the injury has taken place so a ball that will hit a surface of the skin like this it will cause a depression like this and this will lead to the ball being in contact with the skin so over here and over here we will have a spherical or a donut kind of a bruise tram line type Railway track again if the rod is like this and it hits a surface so there will be parallel Road or it will be a parallel track which will look like an appearance like this because the rod is hit here so it is causing a Groove into the skin and the overlying ridges are the ones from which capillary or minimal capillary bleeding is taking place and hence the area in between is the void or looks as if there is no contusion to it in uh Tire trucks that can be easily made out there is a patterned approves like this the pattern of the causative or the offending weapon like a tire can be completely made up this is because of a rod or a spherical object so the healing of contusion like we talked about the age of abrasion we'll be talking about the healing of contusion basically it depends on the hemoglobin component uh what happens is the color of contusion follows a pattern on the almost similar to like this r b b g y so red Red is because of the hemoglobin it is generally fresh it happens in a few within less than one to two hours fresh to one to two hours blue color is because of the reduced hemoglobin in that entry that happens in couple of hours to almost 20 a day brown or black is because of the formation of hemocidrine there it happens in two to three days green is hematoid in five to seven days yellow now this component is sometimes missed and generally from green to the color normal color of the normal skill also takes place yellow is because of bilirubin it takes seven to ten days I will take a moment and try to revise it over here that an abrasion injury was healing within seven to ten days with minimal it had minimal bleeding with no permanent scap formation but in a contusion the yellow color of the skin comes in seven to ten days and it still takes around two weeks to be normal the normal skin that is 0.22 weeks like I've shown hemoglobin gets converted into delivered and gets converted into bilirubin so this is the pattern it forms it is reddish bluish purple green and then yellow and normal skin so this is how it is it is a fresh injury this is 24 hours approximately and hence two to three days five to six days seven to ten days and around 10 to 15 days that is normal it is still not normal some amount of uh recan component can still be made out but more or less we can assume that yes it was normal we'll be talking about migratory bruise over here uh it's basically relatively distant to the site of impact migratory is migration to move from one place to the other so the injury is at site a and we are able to appreciate the bruise at site B this is known as a migratory boost now why does this happen because of the seepage of blood prevented from reaching the surface due to the facial plane Arrangements the original site of injury can be the fracture of floor of the anterior cranial fossa Suppose there is a fracture in the anterior cranial fossa will we see the bruise bruising around the eyes also known as black eye or spectacle hematoma fracture of the floor of the middle cranial fossa this is an important table for McQ point of view fracture of the floor of the middle cranial fossa the bruising of mastoid or battle sign mastoid over the years oh fracture of the jaw bruising in the neck fracture of pelvis bruising over the thigh fracture of females causes bruising over the lower thigh or above the knee then calf injury leads to bruise in the ankle the blood is being seeped down into the ankle so if there is an injury at site a and the bruise is found at side B this is known as a migratory bruise there can be fracture of Android cradle for some metal cranial force of which might be probable questions and definitely these all which you can use your brains and try to answer battle sign so this is a typical battle sign behind the ear where we can see a bruise uh battle sign was named after William Henry battle just a trivia bruising is visible behind and below the ear at the mastoid process caused by the gravitational component accumulation of the blood from a basilar skull fracture so this can be a question what is battle sign where is its scene is it a migratory or an ectopic bruise or not moving ahead a black eye or a spectacular hematoma we discussed because of the fracture of the floor of the anterior criminal fossa it can be also known as raccoon or Panda eyes spectacle hematoma or black eye an injury to the front of the scalp and thus draining they can be three reasons three reasons because of which we can see a black eye or a spectacle hematoma number one we've discussed structure of the skull thus draining blood from the orbital roof injury to the front of the scalp and thus draining the blood Brown over the supraorbital area and direct blow into the orbit so these can be three types of injuries which can cause a black eye or a spectacle hematoma it is not necessarily an anterior cranial fossa delayed bruising so we've talked about pattern we talked about migratory now we are coming down to delayed bruising it is internal bruising of tissues which take times to be visible externally there is nothing rocket science about it the injury has taken place but to come to the surface to be visible externally it is taking time so injury could have taken place on day one and we are able to appreciate it on day three maybe so this is known as delayed brusek second examination after 48 hours this is the key if you are suspecting a delayed Bruce if the history is such that the blues is not visible we should always tell the patient to report after 48 hours so that a re-examination can be taken place we'll be talking about medical legal aspects of Bruce now identification of the causative object yes we can do it if it is a patent Bruce likely told a donut injury a trump Truck Line injury in all those things a pattern is there so yes the weapon can be correlated to the entry times and Century because of that graph of healing the color changes we can talk about it uh we were saying that yes we can the color yellow was something that was not taking place that was not coming in between all the color changes progression true also in some cases uh like in subconjunctival hemorrhage in meningeal hemorrhages please remember these two in subconscious because of the hemoglobin content the color progression is generally not followed so even though it is uh bruised even though there are hemorrhages we will not we might not see a colored progression or time since injury correlating to the day that has been talked about uh differentiating from artificial Brews caused by a marking nut when we'll be talking about semacarpus anacardium it causes a false bruise they can be other medicinal plants also other toxicological plants which cause artificial bruises but yes calorotropis semicarpasana cardium they are known to cause false bruises differentiating from lividity from Bruce that is postmortem lividity from boost it needs to be done drug rules and artificial Roots like I told you the cause is trauma and True Blues but obviously it can be juice of marking nut and calotropus location can be anywhere on the body depending on the injury it is on the only accessible body areas we need to remember that the color will be according to the progression chart or the time says Century this will be generally dark brown and it will not change with time collection of extravisated blood it is collection of accurate serum because of the rupture or the bursting of the capillaries underneath that is why the bruise is happening so there will be extra visited blood in as the collection the Cycles know there will be no recycles but because it is a body reaction it is the accurate Serum is being present so yes there will be the cycle formation in uh artificial Brews so now let's take a two minute break and continue further