Identification: hair growth rate: practice question

A Forensic Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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Forensic Medicine · Identification: hair growth rate

Sample item

A scalp hair segment 6 cm long, cut at the root, is tested for arsenic along its length to find when exposure occurred. Taking the usual rate of scalp hair growth, how much time does the segment span?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. About six months

Scalp hair grows about 1 cm a month (roughly 0.3 to 0.4 mm a day). A 6 cm segment therefore records about six months, and segmental analysis can show when a poison was taken.

Option by option

  • A. About six days

    Six days would need hair growing at about 1 cm a day.

  • B. About six months (correct)

    Correct. At about 1 cm a month, 6 cm covers about six months.

  • C. About six weeks

    Six weeks would need hair growing at about 1 cm a week.

  • D. About two years

    Two years would need much slower growth than normal.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is B, About six months. Scalp hair grows about 1 cm a month (roughly 0.

Why is "About six days" not the answer?

Six days would need hair growing at about 1 cm a day.

Why is "About six weeks" not the answer?

Six weeks would need hair growing at about 1 cm a week.

Why is "About two years" not the answer?

Two years would need much slower growth than normal.

What concept does this question test?

It tests Identification: hair growth rate in Forensic Medicine. 3 to 0.4 mm a day). A 6 cm segment therefore records about six months, and segmental analysis can show when a poison was taken.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Identification: hair growth rate?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.