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🔬 FORENSIC MEDICINE - INJURIES & WOUNDS

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PART 1: CLASSIFICATION OF MECHANICAL INJURIES

1. Blunt force - abrasions, contusions, lacerations
2. Sharp force - incised wounds, stab wounds, chop wounds
3. Firearm - entry/exit wounds, tattooing, blackening
4. Mixed/special - blast, traffic, head injuries

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PART 2: ABRASIONS

• Varies in size; bleeds slightly
• Heals rapidly - NO scar formation (only epidermis involved)
• Raw surface covered by lymph and blood → forms scab/crust

Types of Abrasions (Exam Favourite!)

• Show direction of force (graze)
• Show nature of weapon (patterned/imprint)
• Confirm vital reaction (happened during life, not post-mortem)
• Suggest manner of death (accident, homicide, suicide)

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PART 3: CONTUSIONS (BRUISES)

Memory tip: "Red Blue Green Yellow Normal" = Recently Bought Good Yellow Normal skin

• Age of bruise, site, depth of tissue, amount of blood
• Fair-skinned persons show bruises more easily
• Elderly, anemic, and people on blood thinners bruise easily

• Pattern of bruise may indicate type of weapon used
• Multiple bruises in different stages = repeated assaults
• Post-mortem bruising also occurs but lighter and does not develop same color changes
• "Migratory bruise" - bruise appears at a site distant from where blow was struck (e.g., black eye from forehead blow)

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PART 4: LACERATIONS

Features of Laceration (vs Incised Wound - HIGH YIELD!)

1. Split laceration - blow over bony surface (e.g., scalp over skull)
2. Stretch laceration - tangential force, large skin flap torn
3. Avulsion laceration - entire thickness torn away
4. Penetrating laceration - deep, penetrating organs

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PART 5: INCISED WOUNDS (CUTS)

• Edges: clean, smooth, everted
• Hemorrhage: profuse (cuts blood vessels cleanly)
• Tailing: present (wound tapers at one end)
• Hesitation marks: superficial parallel cuts seen near main wound
• No tissue bridges
• Hair cleanly cut

Cut-throat wounds (Exam Favourite!)

Suicidal vs Homicidal vs Accidental (Summary Table - ALWAYS in exams!)

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PART 6: STAB AND PUNCTURED WOUNDS

• Depth > length (key distinguishing feature)
• Shape depends on the cross-section of the weapon
• Single-edged knife → wound has one sharp angle, one blunt angle
• Double-edged knife → both angles are sharp (slit-like wound, fish-mouth appearance)
• Entry wound is a slit that reseals after weapon withdrawn

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PART 7: FIREARM WOUNDS

Ballistics (Basics)

• Forensic ballistics: Investigation of firearms, ammunition, and problems arising from their use
• Proximal (internal) ballistics: Study of firearm and projectile inside gun
• Exterior ballistics: Motion of projectile after leaving barrel
• Terminal ballistics: Behavior of missile once it penetrates target
• Wound ballistics: Effects of missiles on living tissue

Entry vs Exit Wound (HIGH YIELD!)

Ranges of Fire (SHOTGUN - Exam Favourite!)

Rifled vs Smooth-bore weapons

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PART 8: HEAD INJURIES

Types of Skull Fractures

Intracranial Hemorrhages

Concussion vs Drunkenness (Classic Exam Table!)

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PART 9: TRAFFIC ACCIDENT INJURIES

• Bumper fracture (fender fracture) - fracture of tibia/fibula at bumper height
• This height helps estimate speed of vehicle
• Run-over injuries - tyre tread marks (patterned abrasion), crush injuries
• Throw injuries - from momentum after impact

• Hit from front: victim thrown forward
• Hit from behind: victim thrown backward, may end up on bonnet

• Dashboard injuries: knee/patella fractures
• Steering wheel: chest/steering wheel injury
• Windscreen: facial lacerations, "dicing injuries" from tempered glass
• Seat belt injuries: abrasion pattern across chest/abdomen

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PART 10: WOUNDS - VITAL REACTIONS (HIGH YIELD)

1. Redness and inflammation around wound
2. Hemorrhage - profuse, clotted blood in fresh wounds
3. Swelling of wound edges
4. Repair - granulation tissue, fibroblasts (if survived)
5. Chemical changes - increased histamine, serotonin around wound
6. Leukocytic infiltration (appears in 30-60 min after injury)

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PART 11: WOUND HISTOPATHOLOGICAL TIMELINE

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PART 12: QUICK REVISION - HIGH-YIELD POINTS

1. Abrasion = epidermis only, no scar, shows direction of force
2. Contusion = no skin break, blood under skin, color changes: Red→Blue→Green→Yellow
3. Laceration = blunt force, ragged edges, tissue bridges present, less bleeding
4. Incised wound = sharp force, more length than depth, profuse bleeding, gaping
5. Stab wound = sharp force, more depth than length, slit-like
6. Defense wounds = on ulnar hand - indicates victim tried to defend
7. Hesitation marks = in suicide - multiple superficial cuts near the main wound
8. Tattooing = powder grains in skin, cannot wipe off, close range < 60 cm
9. Entry wound = inverted edges, abrasion collar; Exit wound = everted, larger, irregular
10. Lucid interval = extradural hemorrhage (middle meningeal artery)
11. Battle's sign (mastoid bruise) + Raccoon eyes = basilar skull fracture
12. Vital reaction confirms injury was ante-mortem

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PART 13: IPC SECTIONS RELATED TO INJURIES (Quick Reference)

"Every Doctor Should Remember All Important Permanent conditions"

1. Emasculation
2. Loss of sight (permanent)
3. Loss of hearing (permanent)
4. Loss of any joint/limb member
5. Destruction of any joint/limb
6. Permanent disfiguration of face/head
7. Fracture/dislocation of bone/tooth
8. Any hurt that endangers life or causes severe bodily pain/inability to follow ordinary pursuits for 20 days

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EXAM TIPS - What to Write in Long Essays

• Definition → Mechanism → Features → 4 Types (with examples) → ML importance

• Definition → Mechanism → Color changes table → Factors affecting → Artificial vs True bruise → ML importance

• Always give the differentiation table (10+ points)

• Entry vs Exit table → Ranges of fire (contact to distant) → Shotgun vs Rifle

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• Asphyxia (hanging, drowning, throttling, smothering)
• Thanatology (signs of death, rigor mortis, decomposition, time since death)
• Toxicology (poisons - corrosive, sedative, metallic)
• Sexual offences (rape, POCSO, medico-legal examination)