{
  "fact_registry": {
    "B1": {
      "key": "source_pmc",
      "label": "BMJ 'Medical Myths' peer-reviewed article (PMC/NCBI)"
    },
    "B2": {
      "key": "source_uams",
      "label": "UAMS Health (University of Arkansas Medical Sciences)"
    },
    "B3": {
      "key": "source_factmyth",
      "label": "FactMyth.com science reference"
    },
    "A1": {
      "label": "Verified source count meeting disproof threshold",
      "method": "count(verified citations) = 3",
      "result": "3"
    }
  },
  "claim_formal": {
    "subject": "Human hair and fingernails",
    "property": "post-mortem biological growth",
    "operator": ">=",
    "operator_note": "This is a disproof: we seek >= 3 independent authoritative sources that explicitly reject the claim that hair and nails grow after death. The claim asserts active biological growth continues for days post-mortem. Sources must confirm that (a) growth requires living cellular processes (glucose, oxygen, hormonal regulation) that cease at death, and (b) the appearance of growth is an optical illusion caused by skin dehydration and retraction.",
    "threshold": 3,
    "proof_direction": "disprove"
  },
  "claim_natural": "Hair and fingernails continue to grow for days after a person dies.",
  "citations": {
    "B1": {
      "source_key": "source_pmc",
      "source_name": "BMJ Medical Myths (Vreeman & Carroll, 2007) via PMC/NCBI",
      "url": "https://pmc.ncbi.nlm.nih.gov/articles/PMC2151163/",
      "quote": "Dehydration of the body after death and drying or desiccation may lead to retraction of the skin around the hair or nails. The actual growth of hair and nails, however, requires a complex hormonal regulation not sustained after death.",
      "status": "partial",
      "method": "fragment",
      "coverage_pct": 48.7,
      "fetch_mode": "live",
      "credibility": {
        "domain": "nih.gov",
        "source_type": "government",
        "tier": 5,
        "flags": [],
        "note": "Government domain (.gov)"
      }
    },
    "B2": {
      "source_key": "source_uams",
      "source_name": "University of Arkansas for Medical Sciences (UAMS Health)",
      "url": "https://uamshealth.com/medical-myths/do-a-persons-hair-and-fingernails-continue-to-grow-after-death/",
      "quote": "Hair and fingernails may appear longer after death, but not because they are still growing. After death, dehydration causes the skin and other soft tissues to shrink. This occurs while the hair and nails remain the same length. This change in the body creates the optical illusion of growth people observe.",
      "status": "partial",
      "method": "aggressive_normalization",
      "coverage_pct": null,
      "fetch_mode": "live",
      "credibility": {
        "domain": "uamshealth.com",
        "source_type": "unknown",
        "tier": 2,
        "flags": [],
        "note": "Unclassified domain \u2014 verify source authority manually"
      }
    },
    "B3": {
      "source_key": "source_factmyth",
      "source_name": "FactMyth.com",
      "url": "https://factmyth.com/factoids/hair-and-nails-continue-to-grow-after-death/",
      "quote": "Hair and nail growth requires active, living cells. When a person dies, their heart stops pumping blood, meaning the hair follicles no longer receive the necessary nutrients and oxygen for cell division.",
      "status": "partial",
      "method": "aggressive_normalization",
      "coverage_pct": null,
      "fetch_mode": "live",
      "credibility": {
        "domain": "factmyth.com",
        "source_type": "unknown",
        "tier": 2,
        "flags": [],
        "note": "Unclassified domain \u2014 verify source authority manually"
      }
    }
  },
  "extractions": {
    "B1": {
      "value": "partial",
      "value_in_quote": true,
      "quote_snippet": "Dehydration of the body after death and drying or desiccation may lead to retrac"
    },
    "B2": {
      "value": "partial",
      "value_in_quote": true,
      "quote_snippet": "Hair and fingernails may appear longer after death, but not because they are sti"
    },
    "B3": {
      "value": "partial",
      "value_in_quote": true,
      "quote_snippet": "Hair and nail growth requires active, living cells. When a person dies, their he"
    }
  },
  "cross_checks": [
    {
      "description": "Multiple independent sources consulted to disprove the claim",
      "n_sources_consulted": 3,
      "n_sources_verified": 3,
      "sources": {
        "source_pmc": "partial",
        "source_uams": "partial",
        "source_factmyth": "partial"
      },
      "independence_note": "Sources are from independent institutions: BMJ (peer-reviewed journal via PMC), UAMS (university medical center), and FactMyth (science reference). Each independently explains the myth using the same underlying biology (dehydration/retraction), which strengthens the disproof \u2014 independent sources converge on the same explanation."
    }
  ],
  "adversarial_checks": [
    {
      "question": "Is there any credible scientific evidence that hair or nails actually grow after death?",
      "verification_performed": "Searched for: 'scientific evidence hair nails DO grow after death cells continue dividing briefly'. Reviewed results from PMC, Live Science, Washington Post, BBC Science Focus, Quora, and multiple science sites.",
      "finding": "No credible scientific source supports the claim. Every authoritative source (BMJ, university medical centers, forensic science references) confirms it is a myth. One nuance noted: death is not instantaneous, and some cells survive briefly after cardiac arrest, but this does not include the complex cellular division and protein synthesis required for measurable hair or nail growth.",
      "breaks_proof": false
    },
    {
      "question": "Could brief post-mortem cellular activity produce any measurable hair or nail growth?",
      "verification_performed": "Searched for: 'post mortem cellular activity hair growth brief'. Reviewed forensic pathology explanations.",
      "finding": "While some cells (e.g., skin cells) can survive briefly after cardiac arrest due to residual oxygen, hair and nail growth specifically requires sustained glucose supply, hormonal regulation, and blood circulation. No forensic or medical source documents any measurable post-mortem growth. The BMJ article explicitly states the 'complex hormonal regulation' is 'not sustained after death.'",
      "breaks_proof": false
    },
    {
      "question": "Is the 'skin retraction' explanation itself contested in forensic literature?",
      "verification_performed": "Searched for: 'post mortem skin retraction dehydration forensic science mechanism'. Reviewed forensic pathology descriptions.",
      "finding": "The dehydration/skin retraction mechanism is universally accepted in forensic pathology. It is described consistently across medical, academic, and forensic sources as the explanation for the apparent 'growth' illusion. No credible source contests this mechanism.",
      "breaks_proof": false
    }
  ],
  "verdict": "DISPROVED (with unverified citations)",
  "key_results": {
    "n_confirmed": 3,
    "threshold": 3,
    "operator": ">=",
    "claim_holds": true
  },
  "generator": {
    "name": "proof-engine",
    "version": "0.10.0",
    "repo": "https://github.com/yaniv-golan/proof-engine",
    "generated_at": "2026-03-28"
  },
  "proof_py_url": "/proof-engine/proofs/hair-and-fingernails-continue-to-grow-for-days-aft/proof.py"
}