The cross–sectional size and shape of human terminal scalp hair

Hutchinson, P.E.; Thompson, J.R.

doi:10.1111/j.1365-2133.1997.tb14888.x

Cited by 32 publications

(49 citation statements)

References 4 publications

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“…The major axis showed more variability than the minor axis; this may be due, at least in part, to a change in major axis diameter during the hair cycle. 6 Age-related differences in mean hair diameters and cross-sectional areas have been described previously. Both Trotter 7 and Atkinson and colleagues 8 found the lowest values in children, rising to a peak in early adulthood and declining gently thereafter.…”

Section: Discussionmentioning

confidence: 95%

Hair density, hair diameter and the prevalence of female pattern hair loss

2001

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Hair density in women is distributed as a normal variable, indicating that it is determined as a multifactorial trait. Women with female pattern hair loss have a hair density which falls below the mean but lies within the spectrum of the normal distribution, although other factors, including hair diameter, may affect the subjective impression of hair loss. The hair diameter data suggest that low hair density is not due to progressive diminution in hair follicle size and that follicular miniaturization may occur within the space of a single hair cycle.

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Section: Discussionmentioning

confidence: 95%

Hair density, hair diameter and the prevalence of female pattern hair loss

2001

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“…and cell arrangements as well as related individual changes along a fibre. [2,66,67] This variability offers a large range of options for the imposition of the individual fibre shape. Namely, shifts or a dynamic "blurring" of the interface of the cell fractions along fibre length, possibly unsynchronized with changes of cross-sectional shape, can account for the wide variety of hair curl shapes.…”

Section: Hairs May Show a Wide Variety Of Cross-sectional Geometriesmentioning

confidence: 99%

Why is hair curly?—Deductions from the structure and the biomechanics of the mature hair shaft

Wortmann

Sripho

2019

Experimental Dermatology

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The final shape of a head hair is predetermined through a variety of factors during its formation in the follicle. These are genetic pathways, specific growth factors, cell differentiation and segregation, etc, with spatial as well as chronological dynamics. The cortex of hair consists of two major cell groups. These are characterized by parallel (para‐type) or roughly helical arrangements (ortho‐type) of the intermediate filaments (IF). There are also cell‐specific differences in the disulphide content, that is, of the cross‐link density of the IF‐associated matrix proteins. Given the current state of the academic discussion, we consider it as timely to support and broaden the view that, the structural differences of the cell types together with their lateral segregation are the main driving factor of curl formation. The mechanical effects, which derive thereof, are triggered in the transition zone of the follicle, that is, upon formation of the mature hair shaft. Furthermore, an irregular, “flat” cross section of the hair shaft is shown to be a synergistic but not determining factor of curl formation. The degree of cell type segregation along the mature hair shaft together with dynamic changes of the location of the plane of segregation, namely in a non‐circular cross section can account for very complex curl patterns. Against the background of these views, we argue that contributions to hair curl are implausible, if they relate to physical mechanisms which are active below the transition zone from the living to the mature (dead) hair.

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“…The diameter decreases in hair of the nonpregnant women toward the scalp are comparable to data published previously. 2,3 Similar diameter decreases in hair samples of both the to-be-pregnant and nonpregnant women prior to t 0 were also significant, but are not shown due to an attenuation of the diameter decreases by truncated tapering tips of anagen initiation (Fig. 1), the extent of which cannot be readily estimated.…”

Section: Resultsmentioning

confidence: 82%

“…1 Recently, changes in human scalp hair cross-sectional geometry during anagen have been described, and attributed to intrafollicular causes. 2 When a new hair fibre first emerges from the skin (indicating anagen VI), its diameter is thin and pointed. As it grows for the next 6-8 cm the shaft acquires an increasingly elliptical cross-section in which the diameter (i.e.…”

Section: Introductionmentioning

confidence: 99%

Scalp hair diameter increases during pregnancy

Nissimov

Elchalal

2003

Clinical and Experimental Dermatology

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The hair diameter major-axis has been shown to decrease normally toward the scalp in individual fibres. In this report sharp increases, rather than decreases, of hair-shaft major-axis diameters during pregnancy are described. Mean major-axis hair diameters of 15-20 fibres from each of 12 pregnant and 13 nonpregnant women were measured from the scalp distally at regular 6-mm intervals. Sample diameters were normalized relative to putative times of conception or a distance from the scalp equivalent to full term pregnancy, for the pregnant and nonpregnant women, respectively, and averaged. Major-axis diameter increases toward the scalp in hair of pregnant women were found to start at the beginning of pregnancy with a slope measuring 0.58%/cm, which is highly significant (r = 0.99, P < 0.0001). Hair diameters of the nonpregnant women, on the other hand, decreased toward the scalp during analogous times to the pregnancy, with a slope measuring -0.66%/cm, also highly significant (r = -0.97, P < 0.0001), and in good agreement with previously published data. To our knowledge this is the first description of hair diameter increases during a normal physiological process.

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The cross–sectional size and shape of human terminal scalp hair

Cited by 32 publications

References 4 publications

Hair density, hair diameter and the prevalence of female pattern hair loss

Hair density, hair diameter and the prevalence of female pattern hair loss

Why is hair curly?—Deductions from the structure and the biomechanics of the mature hair shaft

Scalp hair diameter increases during pregnancy

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