Abdominal hair

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Four typical patterns of male abdominal hair growth

Abdominal hair is the

pelage, (hair or fur
).

It connects pubic hair and chest hair.

In humans

Before

androgens (mainly dihydrotestosterone) during and after puberty, the skin of the abdomen begins to produce coarser, longer and more pigmented hair (terminal hair
). This process primarily affects men. Initially, hair grows in a vertical line from the pubic area up to the navel and from the thorax down to the navel. The development of abdominal hair normally begins in the final stages of puberty. With some men, the abdominal hair will stay within a clearly defined vertical line, but in others, terminal hair will appear laterally as well as vertically, particularly in the area around the navel. This lateral spreading can continue into middle age.

Some women may develop a small line of hair from the pubic area up to the navel. Excessive abdominal hair on women, following the male pattern, is a type of hirsutism.

Patterns

  • Horizontal: Characterized by upper surface of pubic hair terminating in a horizontal line with no hair extending to the abdomen.
  • Sagittal: Resembles the first but with the addition of a narrow vertical band of hair extending from the pubic hair towards the navel, often slang called a 'Treasure Trail' or 'Happy Trail'.
  • Acuminate: Characterized by a tapered, inverted 'V' pattern extending upward from the pubic hair. Upper limit may end below the navel, at the navel, above the navel or near the chest.[1]
  • Disperse (or quadrangular): Hair is distributed broadly over the abdomen without forming a discrete geometric pattern.[2]

Richard Zickler performed a 1997 study of photographs of the above patterns and their occurrence in 400 white men and 400 white women,[3] paying particular attention to the development of hair during puberty. In Zickler's study the horizontal pattern was most common in females with an incidence of about 80 percent. The acuminate pattern occurred in about 55 percent of males and occasionally in females. The disperse pattern occurred in about 19 percent of the males studied.[3]

Gallery

  • Accumulative hair growth of an adolescent teen.
    Accumulative hair growth of an adolescent teen.
  • Sagittal hair growth below the navel only
    Sagittal hair growth below the navel only
  • Sagittal hair growth above and below the navel
    Sagittal hair growth above and below the navel
  • Acuminate hair growth around the navel
    Acuminate hair growth around the navel
  • Disperse hair growth on the abdomen
    Disperse hair growth on the abdomen
  • Disperse hair growth
    Disperse hair growth
  • Adolescent male with hair growth below the navel.
    Adolescent male with hair growth below the navel.
  • Female sagittal hair growth
    Female sagittal hair growth

See also

References

  1. PMID 5932294
    .
  2. PMID 6038587
    .
  3. ^ a b Zickler, Rienhard A. (1997). "Sex Differences in Pubic Hair Distribution in White Population". Archived from the original on August 17, 2011.

Further reading

The following journal articles include sketches of different abdominal hair patterns and observed percentages of men exhibiting each pattern.

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