Midphalangeal hair
hair in the ring finger
Midphalangeal hair, or the presence/absence of hair on the middle phalanx of the ring finger, is one of the most widely studied markers in classical genetics of human populations. Although this polymorphism was observed at other fingers as well, for this kind of research, the fourth finger of the hand has been conventionally selected.
Description
In humans, hair is commonly present on all the basal segments of the digits and invariably absent from all the terminal ones. On the middle segments, there is wide fluctuation with apparent familial and racial tendencies. Hair is present on the middle segment of the fingers more frequently than on the middle segment of the toes. Hair is most often found on the middle segment of the fourth finger.
History
Willier (1974), related citations quoted Danforth as stating that 'the hair follicle is a kind of biological microcosm in which almost any problem relating to growth, differentiation, decline and rejuvenescence of tissue can be studied to advantage....' While riding on a streetcar in Wilkes-Barre one summer, Danforth observed, in his own words, that 'a man in front of me draped his arm over the back of the seat and I noticed that while his arm was very hairy the middle segments of his fingers were free of hair and so, I observed, were my own; but I knew this was not generally true.' So far as he was aware, no one before had recognized this variation as possibly hereditary.
Inheritance
The genetic determination of presence or absence of hair on the dorsal aspect of the middle phalanx was first suggested by Danforth (1921). From a study of 80 families with a total of 178 children, he suggested that 'a phylogenetically progressive loss of hair is brought about through the action of one or more recessive genes, or of one primary recessive gene with several modifying factors that regulate the distribution of hair when it is present.' Stated conversely, 'despite the fact that in evolutionary progress hair is disappearing from the mid-digital region, its presence...may be regarded as the manifestation of a dominant trait.'
Bernstein and Burks (1942)
suggested that 5 allelic genes, A-0 to A-4, 'control the inheritance and distribution of middigital hair involving but a single gene substitution (the subscript denoting the number of fingers affected with middigital hair),' and that the genes for the presence of hair are dominant over the genes for its absence.
From a literature review and their own study in Brazil, Saldanha and Guinsburg (1961) suggested that lack of middle phalangeal hair may be determined by a pair of recessive genes, but noted that the occurrence of sex, age, and possibly environmental differences make genetic analysis of the trait difficult.
The public source identifies “Midphalangeal hair” as hair in the ring finger. This brief keeps that definition visible, then builds a research path around Midphalangeal, hair and ring.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Midphalangeal hair”, the useful work is to connect “hair in the ring finger” to the records capable of establishing context and consequence.
The citation trail is more important than the brevity of the summary: it shows where individual claims can be examined in context. The source revision retrieved here is dated Aug 21, 2026. The linked authority identifier is Q19359739. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1974, 1921, 1942 and 1961.
A concise general-reference account can conceal disagreements about scope, terminology or the weight assigned to individual sources. The source lead contains qualifying language; that uncertainty should survive quotation, summary and reuse. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Midphalangeal hair”, its source revision and the description used here.
- Expand the search: follow Midphalangeal hair primary sources, Midphalangeal hair archive and Midphalangeal research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Midphalangeal hair”?
- Which institution is responsible for the underlying evidence?
- What terminology or title could unlock a more precise catalogue search?
Search terms from this dossier
This entry incorporates text from “Midphalangeal hair” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.