Forensic Flashcards
Medicolegal importance of Abrasions?
1.Sign of resistance or struggle.
2.Type of crime : -Throttling -Strangulation/hanging -Smothering -Rape
3.Identification of assailant (Fingernail abrasions, Rope, Bite)
4.Age of abrasion (Day 2 soft scab, day 3 dry scab, Day 7 red surface)
5.Differentiation between contusion & hypostasis (Around contusion)
6.Differentiation between incised and contused wounds (Around contused)
7.Site: abrasions always occur at the same site of injury.
Medicolegal importance of bruises?
1.Signs of struggle or resistance
2.Type of crime : -Throttling -Strangulation/hanging -Smothering -Rape
3.Identification of causal instrument: bruise usually takes the shape of causal instrument
4.Age of bruises (Red -> Blue -> Green -> Yellow) (OxyHb-> ReducedHb-> Biliverdin-> Bilirubin) Each takes 2-3 days and bruise disappears in 2 weeks.
5. Differentiation between incised wound and Contused wound (Around contused)
6. Site: bruises usually occur at the site of injury but it may shift under effect of gravity
The factors that modify the shape & degree of bruises?
1.Type of tissue: bruises develop more easily in soft, vascular, lax tissue than fibrous/toned muscle.
2.Age: infant (delicate skin) & old people (poorly supported blood vessels) bruise more easily than adult.
3.Sex: female bruises more easily (because they have more subcutaneous fat).
4.Color of skin
5. Natural disease: persons suffering from hypertension, vitamins deficiency, liver damage
→ blood vessels become unhealthy and show more bruises.
6.Shape: usually take the shape of causal instrument
7. Site: bruises shift down under the effect of gravity
Antemortem structure of abrasions
Red
Underlying bruise
Healing or sepsis
Vital reaction (Hg, Fibrin threads and infiltration of polymorpho-nuclear leucocytes)
Postmortem is vice versa (IDK WTF THAT MEANS)
Antemortem appearance of bruise
Any size
Accompanied by swelling
may show color changes
blood is clotted in tissues
Postmortem appearance of bruise
Small
No swelling
No color change
Amount blood in meshes of tissue is very slight
Compare between Contused and Incised wound
-Def: Tearing or splitting of tissue VS Drawing of sharp instrument along surface of skin
-Causal instrument: Heavy blunt object VS Sharp object
-example: In rape: tears of hymen VS Cut throat
-Edges: Irregular & lacerated VS Sharp & regular
-Hair at edges: Crushed VS Sharply cut
-Bleeding: Slight VS Free
-Sepsis: Common VS unusual
-Abrasion/Bruise: Present at edges VS absent
-examination of floor: FB VS Clean
-Bridging of tissues across edges: Present VS absent
-Shape: Irregular vs Linear
-Healing: Takes longer time with scar vs Leaves thin scar
How can you differentiate between incised wound and stab wound?
-Def: Drawing a sharp object along the surface of skin VS Forcing sharp pointed instrument
into the body
-Casual instrument: Sharp vs Sharp pointed
-Common example: Cut throat vs stab wound in heart
-Edges: Sharp and regular for both
-Hair: Sharply cut for both
-Length/depth: Length> VS depth>
-Dangerous: Yes and stab is very dangerous because it may injure deep organs and introduce sepsis.
-Relation between wound and size or shape of casual instrument: - VS +
Characters of ante mortem wound
- Gaping edges.
- Swollen and hyperemic edges.
- Blood clot (bruise) infiltrates the edges (not washable under the tapand may show color
changes). - Vital reactions (healing or sepsis).
- Microscopical examination will show infiltration by polymorph-nuclear leucocytes and
fibrin threads.
Postmortem wont show any of the above!
Causes of death of cut throat?
- Neurogenic shock due to reflex vagal cardiac inhibition.
- Hemorrhage from carotid arteries and jugular veins.
- Chocking: trachea is opened and blood may be inhaled.
- Mechanical asphyxia:- in cases of complete division of trachea, the soft parts of the neck fall in and close the air way to cause death from mechanical asphyxia.
- Venous air embolism
- Delayed death
Sepsis
Infection of larynx, edema of glottis
Bronchopneumonia
Lung injuries
- Penetrating wounds
- Blow to the chest: bruising of lung, which may be, diffuses and spread over long surface or localized.
- Major blow to chest → broken ribs with sharp ends may be forced into chest cavity and lacerate underlying lung. In old people cause pneumonia and children may get away without fracture of ribs since they’re malleable.
Heart injuries
1.Blow to chest → contusion of heart, death occurs several days after injury from delayed effects of cardiac damage.
2.Major blow to chest → laceration of Heart in any chamber, usually ventricles, because their anatomical position making them more exposed to trauma than atria.
3.A blow to the chest → may cause sudden death by reflex vagal cardiac inhibition.
4. Stab wound in the auricle or big vessels causes immediate fatal bleeding because their walls are thin. While stab wound in ventricles, patient may survive for some days because of their thick wall.
5. Stab wounds of the right ventricle are more rapidly fatal than those of the left ventricle.
6. Subendocardial hemorrhage: it may occur in cases of death from hemorrhage, poisoning by arsenic, phosphorus, blood disease, burning and from trauma to chest.
7.Rupture of heart may be traumatic due to severe blow to the chest or pathological due to aneurysmal dilatation with any sudden effort.
Diaphragm injuries
- Blow to chest or abdomen → rupture of diaphragm
- Rupture of left dome is more frequent than rupture of right dome due to its protection by
the liver.
Liver injuries
blow on abdomen may cause lacerations of liver. These lacerations may shallow & split capsule especially over right lobe of liver or severe & separate right and left lobes of liver with severe bleeding inside peritoneal cavity
Spleen injury
- Malaria and schistosomiasis render the spleen larger and more friable.
-The minimal trauma in these cases may cause severe rupture of spleen.
