Sexual Assault

🔎 Overview

Sexual assault is any non-consensual sexual act, often involving physical force, threats, or manipulation. In forensic pathology, the focus is on cases where sexual assault resulted in death, such as rape-homicide. These require:

• Full external and internal examination,
  
  

• Collection of DNA, fluid, and trace evidence,
  
  

• Collaboration between forensic pathologists, scientists, and police.
  
  

🧬 COMMON MODES OF DEATH IN SEXUAL ASSAULT

1. Strangulation

• Often used to subdue or kill the victim.
  
  

• Signs:
  
  

  • Petechiae (tiny red/purple spots) in the eyes/face from ruptured capillaries,
    
    

  • Neck bruising or abrasions,
    
    

  • Fracture of hyoid bone or thyroid cartilage (examined during autopsy).
    
    

2. Head Injuries

• From blunt trauma (e.g., hitting or kicking the head).
  
  

• Signs:
  
  

  • Scalp injuries,
    
    

  • Skull fractures,
    
    

  • Intracranial bleeding (subdural/epidural hematomas),
    
    

  • Brain contusions or lacerations.
    
    

3. Stab Wounds

• Less common but may reflect sexualized violence.
  
  

• May be clustered on breasts, genitals, or buttocks.
  
  

• Important to examine:
  
  

  • Number, depth, and angle of wounds,
    
    

  • Weapon characteristics,
    
    

  • Position of attacker.
    
    

4. Pelvic Trauma

• Severe genital or rectal injuries, especially in children, can cause:
  
  

  • Hemorrhage (massive bleeding),
    
    

  • Infection from damaged tissues or foreign objects.
    
    

🔍 EXTERNAL EXAMINATION TECHNIQUES

1. General Body Exam

• Inspect entire skin surface for:
  
  

  • Bruises, abrasions, scratches, bite marks,
    
    

  • Common sites: neck, breasts, arms, thighs.
    
    

• Use alternate light sources (UV or blue light) to detect:
  
  

  • Bruising,
    
    

  • Seminal fluid or lubricants.
    
    

2. Perineal (Genital and Anal) Exam

• Check labia, vagina, anus for:
  
  

  • Lacerations, abrasions, bruising,
    
    

  • Foreign materials (e.g., pubic hair, lubricant, condoms),
    
    

• Swabs should be collected for:
  
  

  • DNA,
    
    

  • STI testing.
    
    

3. Oral Cavity

• Look for signs of oral penetration:
  
  

  • Petechiae on palate,
    
    

  • Inner lip bruises,
    
    

  • Broken teeth or dental trauma,
    
    

  • Male DNA or semen.
    
    

4. Documentation

• Take clear photographs with scale markers.
  
  

• Describe all injuries in measured detail.
  
  

• Preserve all evidence with proper chain of custody.
  
  

🔬 INTERNAL EXAMINATION CONSIDERATIONS

1. Genital Tract Dissection

• Open the vagina, cervix, uterus to examine:
  
  

  • Internal injuries,
    
    

  • Hidden bleeding,
    
    

  • Foreign objects.
    
    

• Similar approach for anal canal.
  
  

2. Toxicology

• Collect:
  
  

  • Blood, urine, and vitreous humor (eye fluid).
    
    

• Test for:
  
  

  • Alcohol, recreational drugs, or date-rape drugs (e.g., GHB).
    
    

3. DNA Collection

• Swabs from:
  
  

  • Vagina, anus, mouth, skin, fingernails,
    
    

• Store clothing and bedding.
  
  

• Handle all biological evidence with care to prevent contamination.
  
  

👄 ORAL & FACIAL INJURIES IN SEXUAL ASSAULT

1. Lip/Buccal Mucosa

• Signs of oral penetration:
  
  

  • Abrasions, lacerations, or bruises inside cheeks/lips.
    
    

2. Swabs Before Touching

• Always collect oral swabs before opening the mouth to prevent DNA loss.
  
  

3. Modern Analysis

• Even without sperm, male DNA can be detected using epithelial cell analysis.
  
  

🧍‍♀️ BODY SURFACE INJURIES

1. Breast Injuries

• Bruises, particularly around nipples.
  
  

• Linear abrasions from nails.
  
  

• In rare cases: nipple amputation.
  
  

2. Thigh & Buttocks

• Inner thigh bruises = forced leg separation.
  
  

• Buttocks: signs of anal assault.
  
  

3. Back & Shoulders

• Injuries indicate struggle or sex on rough surface.
  
  

4. Bite Marks

• Circular bruises with intradermal petechiae (suction marks),
  
  

• May need forensic dentist to match teeth to bite.
  
  

🧪 EVIDENCE COLLECTION PRINCIPLES

• Use both dry and moistened swabs.
  
  

• Duplicate samples for safety.
  
  

• Store swabs at -20°C to preserve DNA.
  
  

• Photograph all injuries before healing alters their appearance.
  
  

⚰️ SEXUAL HOMICIDES — PATTERNS & AUTOPSY TECHNIQUES

1. Wound Patterns

• Injuries often focus on:
  
  

  • Breasts, vulva, buttocks, thighs.
    
    

  • Suggest sexual symbolism or sadistic behavior.
    
    

2. Mutilation

• May include:
  
  

  • Genital cutting,
    
    

  • Breast removal,
    
    

  • Decapitation or organ removal.
    
    

3. Ritualistic Signs

• Object placement,
  
  

• Body positioning,
  
  

• Can indicate psychological or ritual motives.
  
  

🔧 AUTOPSY TECHNIQUES FOR EVIDENCE

1. External

• Check back for pressure marks (e.g., rape on ground).
  
  

• Ligature marks on neck or wrists.
  
  

2. Nail Scrapings

• Use wooden sticks to collect DNA from under nails.
  
  

3. Pelvic Organ Removal

• Remove entire genital-anal block to examine injuries thoroughly.
  
  

4. Bladder

• Empty & retain urine for drug tests.
  
  

🩸 ANAL EXAMINATION & PEDIATRIC CARE

• Inspect anus and perianal area for:
  
  

  • Lacerations, bruising, sphincter dilation.
    
    

• Note:
  
  

  • Anal dilation can occur after death → not always evidence of assault.
    
    

• Pediatric cases:
  
  

  • Consider normal anatomy to avoid misdiagnosis.
    
    

  • Take a trauma-informed approach.
    
    

🧪 SEMEN & DNA DETECTION

1. Visual Clues

• Dry stains: silver, stiff patches on clothing or skin.
  
  

• UV light: semen fluoresces bluish-silver.
  
  

2. Enzyme Tests

• Acid phosphatase: High in semen; early indicator.
  
  

• Prostate-Specific Antigen (PSA): Present in male fluids.
  
  

3. Microscopy

• Sperm detection = strong evidence.
  
  

• But some men (e.g., vasectomized or azoospermic) have no sperm.
  
  

4. DNA Testing

• Y-chromosome STRs: Identify male DNA even in mixed samples.
  
  

• PCR & FISH: Highly sensitive methods.
  
  

• MicroRNAs (miRNAs): New technique for identifying specific body fluids.
  
  

⚠️ HOMOSEXUAL ASSAULT CONSIDERATIONS

• Examine for:
  
  

  • General trauma, anal bruises, rectal tearing,
    
    

  • Semen or lubricants in anus or rectum.
    
    

• Note:
  
  

  • Postmortem relaxation may mimic assault (e.g., dilated anus).
    
    

• Evidence:
  
  

  • Collect anal, oral swabs,
    
    

  • Preserve blood, lubricants, and pubic hair.
    
    

🧾 FINAL FORENSIC PRINCIPLES

1. No injury ≠ No assault
   
   

   • Many victims show no physical signs, but were assaulted.
     
     

2. Injuries need context
   
   

   • Bruising in children = more concerning than in adults.
     
     

3. Photograph, Swab, Document
   
   

   • Every step is crucial for legal evidence.
     
     

4. Chain of Custody
   
   

   • Maintain traceable control of evidence for court admissibility.