Written by Dr. D. Rao

Different medico-legal questions which may arise in connection with hair are related to identification of a person and other medico legal aspects. To enumerate them,

  1. Concerning identification of a person:
    1. Is the material hair or some other fibre?
    2. If hair is it human or animal hair?
    3. If of human being, then it’s, (a) race, (b) sex and (c) age.
    4. Whether bleached or any dye has been used,
    5. if hair bulb is present, then the blood group of the person concerned.
    6. if any idea about the occupation of the person concerned can be made from the hair.
    7. If any trace material (trace evidence) can be detected from the hair, which can help identification of the person concerned.
    8. Is the hair identical with the hair of the victim or the accused?
  1. Concerning other medicolegal aspects:
    1. To which part of the body did the hair belong? (It is important in circumstances like rape or other sex offences as in case of detection of pubic hair or hair from around the region of anus.)
    2. Whether taken out forcibly or fallen off naturally (to indicate presence o r absence of struggle)?
    3. To establish a relationship between an offence, offender and the victim (e.g. detection of a foreign female pubic hair on the glands penis of the accused in an alleged case of rape), and sometime the offending weapon (as in case of assault with the weapon).
    4. Cause of death.
    5. Type of injury.
    6. Type of weapon used.
    7. When nature of death is homicidal, presence of hair in the grip of the hand of the deceased which is in a state of cadaveric spasm, tell about the homicidal nature of the death and help detection of the assailant, if the hair did not belong to the deceased himself.
    8. Detection of certain poisoning cases.
    9. Singeing of hair has importance in death due to burn or fire-arm injuries.
    10. Time since death can be estimated from the length of facial hair in male subjects, with habit of shaving.
    11. Presence of trace evidence like presence of blood of a person other than the victim, and semen are helpful in criminal investigations.
  1. Hair has a special medico-legal importance concerning identification and other medico-legal aspects in that, hair resist putrefaction or decomposition for a pretty long period which makes it an extremely helpful tool in medico-legal practices.

Details on medico-legal aspects of hair:

A1. Is the material hair or some other fibre?

Hair may very occasionally be confused with some other fibre, vegetable origin like, cotton or jute fibres, semi synthetic fibres like those manufactured from cellulose or purely synthetic fibres like nylon, polyvinyl or polyester fibres. Natural fibres can be known by naked eye and microscopic examination. For synthetic fibres, to know their exact nature, certain other tests are necessary. Human and animal hair have distinct morphological features which are discussed after description of other fibres.

Description of fibres -

COTTON FIBERS are flattened and twisted. Microscopically they have long tubular cells.

JUTE fibres are smooth fibres with irregular cell cavities.

SILK fibres are fine, long filaments having no cells in them.

SYNTHETIC FIBRES are non-cellular fibres of varying thickness, elasticity, contractibility, density, solubility and chemical composition. To differentiate them from one another, tests for these properties are performed.

A2. Is the hair a HUMAN hair or an ANIMAL hair?

The difference between human and animal hair can be drawn on the following points:

  1. Usually the human hair is comparatively delicate, but animal hair is coarse except ventral hair of some species.
  2. Human hair is black, grey, reddish or reddish-brown in colour but animal hair may be of any colour. Even a single animal hair may have different colours at different parts.
  3. The cortex makes the maximum thickness of the shaft of human hair, which is much more than in animal hair. The cortex is always more than 4 times thicker than the medulla in human hair. The proportionate thickness is not so high for the cortex in case of animal hair.
  4. Medulla in human hair is very narrow, may be continuous, interrupted, fragmented or even absent in some hair. In animal hair medulla is always present, is broader, continuous, and may sometimes have ladder or lattice arrangement. In animals, the thickness of the medulla is not less than half of the thickness of the cortex.
  5. Pigment in human hair is usually distributed more abundantly towards the peripheral zone of the cortex, in contrast with animal hair.
  6. The scales in the cuticular layer of the human hair is flattened, with irregular serrated margin and is of the imbricate type. According to the classification of Mortiz it belongs to type VII. The cuticular scales of the animal hair may be of any variety of the coronal or imbricate type. According to the classification of Moritz, any of type I to VII may be present in animal hair.
  7. Precipitin tests are specific for different species and can differentiate human hair from other animal hairs.
A3. RACE, SEX and AGE of the person from the hair –
  1. RACE:
    In European and American Caucasoids,the hair is delicate in texture, straight or curly in shape and pale, reddish or reddish brown in colour.
    In Mongoloids, the scalp hair is medium in texture, straight in shape and black in colour.
    In Negroids, the hair is thick or coarse in texture, extremely curly or woolly in shape and black in colour.
    In Indians, the hair is medium in texture, straight or curly in shape or form and black in colour.

  2. SEX from hair –

    In MALES, the hair is comparatively
    thick or coarse. Scalp hair is comparatively shorter. Facial hair and hair on other parts of the body namely chest and limbs, are abundant and distribution of pubic hair has upward extension with the apex near the umbilicus. Microscopically, Barr bodies are very rare in the cells of the hair bulb.

    In FEMALES, the hair is comparatively thin or delicate. Scalp hair is comparatively longer. Distribution of hair is usually limited in the scalp, axilla and pubic regions. Distribution of pubic hair is limited in a transverse straight line, a short distance above the mons veneris. Microscopically, Barr bodies are comparatively more common in the cells of the hair bulb.

  3. AGE form hair
    The scalp hair appears in a foetus in 5th month and the downy lanugo hair on the body of the foetus appears in the 4th month. At birth, scalp hair is about 4-5 cm. in length and the lanugo hair is distributed only on and around the shoulders. Pubic hair appears by 13th/14th year in girls and 14th/15th year in boys. Axillary hair appears by 14th/15thth/16th year in boys; Facial hair appears in boys between 16th -18th year, first moustaches, followed by beards. With extreme variation, scalp hair starts greying by 40 years, pubic hair greys above 50 years and body hair above 60 years, usually. Baldness may appear in males by about 50 years. Females usually do not go bald. year in girls and 15
A4. Whether BLEACHED or any DYE has been used –

When bleached, hair appears pale or colourless and when dyed it takes the colour of the dye. Grey hair is usually dyed with black dye. In some community hair is beached and then dyed with ‘mehendy’ to give a reddish brown colour to the hair. When dyed, the time passed after dyeing can roughly be calculated out from the length of the hair near the root which has grown after dyeing of the hair and does not show the presence of the dye. Chemical analysis of the dye used can also help to identify an unknown person or dead body.

A5. BLOOD GROUP of the person from hair –

If hair bulb is present then, the blood group of the person can be determined by “absorption-elution technique” or mixed agglutination technique.

A6. Hair and OCCUPATION-

Occupation of a person can be guessed form the hair if trace elements can be detected from his hair, by using modern scientific investigation processes including neutron activation analysis, if the hair of the person is or was vulnerable to be contaminated in course of his occupation with the trace elements to be detected in his hair. In occupations, where the person is exposed to substance like arsenic, the same may be detected in his hair. In aniline industries, the hair of the workers may have a bluish tinge and in copper industry it may have greenish tinge. In miners and some other industrial workers, there may be early baldness. In some industries, hair of the workers may become brittle and lustreless.

A7. If any TRACE ELEMENT present –

Trace elements as discussed in A6 above will help identification of the person. Trace evidences like blood or semen may help to identify the assailant or the rapist by grouping test of the blood or semen present.

A8. Is the hair identical with the hair of the victim or the accused?

If the sample hair is studied against the hair of the accused or victim on all the points discussed in above paragraphs, then it can be said whether the sample hair belonged to the accused or the victim.

B1. To which BODY PART the hair belonged?

This can be determined form the length, shape, texture and some other features of the hair.

Scalp hair is long, straight or wavy or curly and medium in texture in Indians. In males, the tip may be flat if the subject had recent hair cut. In cross section, the cut surface is circular or oval or plano-convex, depending on whether the hair is straight, wavy or curly.

Beards and moustaches are short in length (length may be up to 3” for moustaches and 10” for beards), wavy or curly, thick or course and tip may be flat, if recently shaved. In cross section, the cut surface is plano-convex or triangular.

Eyebrows and eyelashes are short, curved, thick and taper to the tip. In cross section, the cut surface is plano-convex or triangular.

Axillary hair is short, straight or curly, thick or coarse and the tip may be splitted or frayed. Cut sections have nothing in specific.

Pubic hair is short, curly, and thick with splitted or frayed tip. Cut section has oval or triangular surface.

Nasal hair is very thick, short, curved with triangular cut surface.

Hair on other parts of the body is short, curved, and thick with triangular cur surface.

The body part to which the hair belonged, is important, to know, whether it was a case of assault on the head or a case of sex assault viz. rape or sodomy.

B2. Whether taken out forcibly or fallen off naturally –

A hair taken out forcibly, will have a full roundish hair bulb covered with a torn sheath. A hair fallen off naturally, will have no bulb and sheath at its root end. If the hair has been taken out forcibly, that indicates fight or struggle.

B3. Relationship between the OFFENCE, OFFENDER, VICTIM and sometimes the OFFENDING WEAPON –

If a female pubic hair is detected on the glands of the accused of a case of rape or if a male pubic hair is available near the private parts of the victim of a case of rape, then relationship between the offence, offender and victim can be established by studying the sample hair recovered from the male or female genitalia and the pubic hair of the victim or the accused. Similar is the position in sodomy cases (pubic hair of the active agent and anal hair of the passive agent) and bestiality cases (pubic hair of the accused found near the anus or vagina of the animal and the animal hair near the private parts of the accused). If it is a case of mechanical assault, then hair may be present in the weapon recovered from the possession of the accused, which may be compared with the hair of the victim to establish relationship between the offence, accused, victim and the weapon of offence.

B4. CAUSE of death –

In death due to head injury, the hair of the affected part of the head may be crushed or may show sharp cutting, depending on whether hard, blunt or sharp cutting weapon was used. In death due to arsenic poisoning, the poison may be detected in the hair.

B5. Type of INJURY –

In case of lacerated injury over head, the hair bulb is crushed. In case of incised or stab wound, the hair is sharply cut.

B6. Type of WEAPON used –

In case of head injury, if the hair bulbs are crushed then it can be said that hard, blunt weapon has been used. If there is sharp cut on the hair, then a sharp cutting weapon must have been used.

B7.    NATURE of death –

In homicidal cases the hair of the assailant may be held in tight grip of the hand of the victim in a state of cadaveric spasm, as a result of struggle before death.

B8. Detection of POISON –

In chronic arsenic poisoning, when the patient is still surviving, hair serves as good material for detection of the poison and diagnosis of the case.

B9. SINGEING of hair –

In burning cases the hair get singed. Singeing of hair, of course, does not specifically indicate ante-mortem or postmortem nature of the burning. It is a point to differentiate between ulcers due to burn, scald or chemical agent. In fire-arm injury cases, singeing of the hair around the wound indicates about the short distance of the firing. If hair around the wound is singed, then muzzle end of the weapon was within a distance from which the fire from the muzzle end could travel up to the body of the victim at the time of the firing.

B10. Estimation of TIME OF DEATH –

In case of death of a male subject, if the date and hour of his last shave is known (e.g. from the fixed barber), then from the length of the beards and moustaches, or beards alone, it can be said, for what period the deceased survived after his last shave. This identity gives the time of death. (Rate of growth of

B11. Detection of some TRACE EVIDENCES in hair –

See column A6 and A7 above.


Hair resist putrefaction and thus can help to identify the deceased and at times can help to know the cause of death (see Col. B4.), even years after death when hair and/or bones may be the only available remains of the dead body.