In chronic arsenic (inorganic) poisoning, Mees' lines are observed on the fingernails. The correct statement about Mees' lines in the forensic context is:
- A Mees' lines are transverse white bands representing disrupted keratinisation; their position from the nail base allows estimation of the time of arsenic exposure (nails grow ~1 mm per 10 days) ✓
- B Mees' lines are brown longitudinal streaks indicating active arsenic deposition in nail matrix
- C Mees' lines are pathognomonic of arsenic poisoning and cannot be caused by any other condition
- D Mees' lines appear within 48 hours of arsenic ingestion, allowing acute poisoning to be distinguished from chronic
Explanation
Mees' lines (Aldrich-Mees' lines) are transverse white bands across the nail caused by disrupted keratinisation during episodes of arsenic toxicity. Since nails grow approximately 1 mm per 10 days, the position of Mees' lines from the lunula allows forensic estimation of when the arsenic exposure occurred — a band 10 mm from the lunula indicates exposure roughly 100 days prior. They are not pathognomonic; identical lines occur in thallium, selenium poisoning, renal failure, and severe systemic illness. They do not appear acutely within 48 hours.
Reference: The Essentials of Forensic Medicine and Toxicology (Narayan Reddy), 34th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.