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Physical and structural age changes in human skin.

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PHYSICAL AND STRUCTURAL AGE CHANGES
I N HUMAN SKIN
MARJORIE M. C. LEE '
Department of Anatomy, University of Hong gong, Hong Kong
FIFTEEN FIQUBES
INTRODUCTION
Work on age changes of the different components of the
dermis has been done by many authors, but the results do not
quite agree with each other in many respects. Schmidt (1891)
found that degenerative changes in the elastic tissue of the
skin first appear at age 40. Reizenstein (1894) found similar
changes in facial skin starting at 26 to 28 years. I n unexposed
skin, Lindholm ('31) found that elastic fibers were more
numerous in children than in adults and in females than in
males. Ejiri ('38) found that changes occur in both elastic
and collagenous fibers with age, more intensive changes in
men than in women. Hill and Montgomery ( '40) studied unexposed skin and found no evidence of senile changes in the
elastic or collagenous fibers. Dick ( '47) found changes in the
elastic tissue in different age groups and at different sites of
the body, but he reports little evidence of sexual differences
in elastic fibers. Strobe1 ('48) studied unexposed skin and
concluded that the principal atrophic change with age is in
the collagenous fibers and that there is no degenerative change
in the elastic fibers. Ma and Cowdry ('50) found an evident
decrease in elastic tissue in the superficial part of the dermis
of the antecubital region in individuals over 78 years. The
'This study was begun in Hong Kong, but completed in the Department of
Anatomy, Wayne State University, Detroit, while the author was a research fellow there.
473
474
MARJORIE M. C. LEE
greatest difference with age seems to lie between the skin of
exposed and unexposed areas.
Physical properties of the skin, especially tension and elasticity, were tested by many workers. Sodeman and Burch
('38) measured the skin distensibility at various sites in the
living body. Dick ('47) measured the tension and resistance
to stretching of cadaver skin of both young and old people.
Kirk and Kvorning ('49) recorded the indentation and rebound of skin in the living body of both young and old people.
Ragnell ('54) measured the tensibility of skin in regard to
Langer's lines. These studies were done either directly on
the living body or on the skin removed from the cadaver but
set up in a condition with the same tension before its removal.
The tension of skin was described as high in young people
and lower in the aged, but no histological studies were made
on the skin which had been used to test the physical properties.
I n the present study, samples of skin from both exposed and
unexposed areas of the body were chosen, and stretching of
the skin of all age groups was tested from a state starting
with no tension, so that the real physical properties can be
better interpreted; for instance, if the same quality and same
size rubber gloves are worn by large and small hands, the
tension of the rubber gloves will be higher on the large hand
and lower on the small hand, though they are identical gloves ;
therefore the true nature of the rubber can be better shown
after they are removed from the hand. I n an endeavor to
explain the age changes in the physical properties of the skin,
each specimen was examined histologically after its stretch
and recoil were tested.
MATERIAL AND METHODS
Vertical strips of whole thickness of skin with some subcutaneous fat attached, 10 mm wide and 35 mm long, were removed at necropsy from Chinese people in Hong Kong; no
specimen was taken if there was any indication of a pathological condition of the skin. Skin specimens were taken from
AGE CHANGES IN HUMAN SKIN
475
two sites: (1) the middle of the forehead to represent exposed skin, (2) the front of the forearm (antecubital region)
to represent unexposed skin.
I n both the study of ageing of the epidermis by Evans, Cowdry and Nielson ('43) and the study of the ageing of elastic
tissue in human skin by Ma and Cowdry ('50) skin of the
antecubital region was used. The reasons for its preference
were given by these authors as: it is protected by its position
from radiant and mechanical trauma even when uncovered;
clothing usually is loose and rubbing is minimal; suf6cient
slack is provided partially to compensate for the pulling and
stretching of movement ; the relative efficiency of evaporation
and the absence of apocrine glands minimize a possible
physico-chemical interference. In addition, Chinese, especially
older people, usually cover the forearm with long sleeves even
in summer, so it can really be considered as unexposed skin.
Specimens were taken from 39 individuals, males and females. I n 4 cases the age was unknown, the remaining 35
individuals ranged in age from 4 months to 84 years.
To test the degree of stretching of the skin, a simple procedure was tried. As the vertical strip of the skin was
removed from the body, it was suspended from near its upper
end on a fine metal hook, two small spots 20mm vertically
from each other were marked with Indian ink on the skin,
then a weight of 10 gm was applied near the lower end with
another hook, the two dots and two hooks being kept in a
straight line. The stretching of the skin was recorded by
measuring the distance between the ink marks which were
originally 20mm apart. The degree of recoil of the skin was
tested by removal of the weight and measurement of the distance between the two ink marks again.
F o r microscopic studies, small pieces of skin were taken
from the middle of the skin strip after testing its stretch and
recoil. They were fixed for 24 hours in 10%formalin saturated
with corrosive sublimate; paraffin blocks were made by the
standard procedure. Sections were cut at 6p always perpendicular to the long axis of the vertical skin strip. Ehrlich's
476
MARJORIE M. C. LEE
hematoxylin and eosin were used for all specimens, and alcoholic orcein was used to demonstrate the elastic fibers.
OBSERVATIONS AND RESULTS
Stretch amt recoil
The skin stretches linearly, responding to the application of
a 1 O g m weight. As skin strips are all taken in the same
vertical direction, Langer 's lines should not influence differences in stretching.
Skin of the foreurm: in the young age group, starting with
infants of 4 months old, the skin stretches relatively little, the
degree of stretch increases steadily and rapidly until it
reaches a maximum about the end of the second or beginning
of the third decade, from there on it decreases gradually with
advancing age. The maximal reading from my series of cases
is a female 23 years old; the skin stretches 81% (from 20 mm
to 36.2 mm) which is over three times as much as that of the
4 month old boy in whom the increase is only 26% (from 20 mm
to 25.2 mm). By the seventh decade the stretching of the skin
becomes as low as that of the infants, and there is a tendency
to show further decrease in still older people (table 1, fig. 1).
There is a strong relationship of degree of stretch t o age. The
coefficient of correlation ( r ) between the forearm skin and
age was calculated; f o r individuals under 20 years r =0.80,
from 20 years on r =-0.90.
These correlations are quite
high, although with opposite signs in the young and old,
The degree of recoil was also recorded after removal of the
weight from the skin strip. None of the specimens recoiled
completely back to the original length (table 1). No sex difference was observed in either the degree of stretch or recoil.
Skin of the forehead: in 26 of the individuals of known age,
I received permission to take a skin specimen from the forehead. I n these individuals the degree of stretching of the
skin of the forehead also shows a definite change according
to age. Unlike that of the forearm, it is in a single direction:
the younger the subject, the more it stretches. I n the 5 month
477
AGE CHANGES I N H U M A N SKIN
TABLE 1
Length, after adding 10 g m weight, of strips of skin which had been 20 mm long;
length after removal of the weight, and t h i c h e s s of the dermis
SKIN OF FOREARM
Length
Length
during
after
sumension removal of
of -weight
weight
AQB
4 mo.
5 mo.
1yr.
1yr.
4 yr.
6 yr.
8 yr.
8 yr.
9 yr.
13 yr.
M
F
M
F
I?
F
F
M
F
M
SKIN OF FOREREAD
Thickness
of dermis
Length
Length
after
Thickness
during
sumension removal of of dermis
of weight
weight
mm
mm
mm
mm
mm
mm
25.2
28.0
25.5
27.0
29.0
22.5
21.5
20.8
20.9
21.5
0.56
0.85
0.67
0.69
0.51
27.5
27.2
26.0
27.0
21.0
22.5
20.4
21.4
0.82
0.50
0.66
0.62
31.5
32.5
33.8
35.2
32.3
21.5
20.5
20.5
21.0
20.8
0.85
0.90
0.68
0.87
1.15
25.0
25.5
24.8
26.0
20.5
20.8
20.8
20.8
0.96
0.71
0.81
0.86
32.8
32.5
36.2
32.0
30.0
21.0
20.5
21.2
21.8
21.0
1.19
1.46
1.04
1.82
1.41
26.0
24.5
24.2
20.3
21.0
21.5
1.17
0.82
1.64
32.8
33.0
33.0
26.3
30.8
21.5
21.0
21.2
21.0
21.5
1.67
1.24
1.15
I .73
1.43
22.5
22.8
21.2
21.0
0.92
0.70
21.5
21.0
21.0
21.0
21.5
1.35
1.33
1.00
1.21
0.82
24.5
24.0
23.9
21.0
21.3
21.0
1.15
1.18
1.44
23.0
21.2
0.85
14 yr.
15 yr23 yr.
27 yr.
28 yr.
M
M
29 yr.
30 yr.
34 yr.
35 yr.
35 yr.
M
35
10 yr.
40 yr.
41 yr.
41 yr.
43 yr.
M
M
M
M
F
30.2
29.8
29.7
29.5
28.0
45 yr.
45 yr.
47 yr.
50 yr.
51 yr.
M
M
M
M
F
26.5
29.5
27.5
26.0
27.0
21.5
22.0
22.2
21.7
22.0
1.25
0.86
1.25
1.17
0.84
24.2
22.8
21.5
21.2
1.01
1.19
24.0
23.2
21.3
21.0
1.58
0.76
54 yr.
62 yr.
65 yr.
73 yr.
84 yr.
F
M
29.2
25.2
27.0
25.0
22.2
21.0
22.0
22.0
21.5
20.6
0.68
0.92
0.86
0.62
0.46
23.0
22.5
22.8
24.0
21.0
21.5
20.8
21.1
21.5
20.5
0.59
1.16
0.95
0.81
0.86
F
M
M
F
M
M
M
F
M
478
MARJORIE M. C. LEE
old female infant, the forehead skin stretches 37.2% (from
20 mm to 27.5 mm), and in the oldest subject, an 84 year old
man, it stretches only 5% (from 20mm to 21mm) (table 1,
fig. 2). Individual variability is also present here, and the
'1
*,0
*O
0
Male
\
a 0
0
Female
P
2o
t
I
I
I
20
I
I
40
4 e in years
I
I
I
80
60
L
Fig. 1 Stretch of forearm skin by 10 gm weight. The subjects are arbitrarily
dividt-td a t 20 years of age in the regression lines which are plotted.
0
20
0
.*
30
-
Q
O .
*.
Female
0
AGE CHANGES IN H U M A N SKIN
479
coefficient of correlation, r, equals -0.83. This shows a high
statistical significance for the change in the degree of stretching of the forehead skin with age.
The condition of recoil is similar to that in the forearm;
that is, all specimens fail to go back to the original length
after removal of the weight. No apparent sex difference was
observed (table 1).
----
Stretch of Forearm Skin
Stretch of Forehead Skln
Age
in years
Fig. 3 Comparison of the degree of stretch of the forearm and the forehead
skin. The mean values for each 5-year interval are plotted.
Comparing the results of the degree of stretching in the
forearm and in the forehead, the forearm skin tends to stretch
much more than that of the forehead. By plotting the curves
of the mean value of stretching in 5 year intervals for both
forearm and forehead on the same diagram (fig. 3), it can be
seen that the average of the first 5 years of the forearm is
34.7%, and the forehead is 34.6%, so that the values of the two
areas are almost identical. I had very few samples in the very
old group. Judging from the two subjects at the upper end of
my series, the stretching is 25% and 20% for the 73 year old
female, 11% and 5% f o r the 84 year old male, f o r the forearm
and forehead respectively. It still shows a lower value in the
stretching of the forehead than the forearm, but the differ-
480
MARJORIE M. C. LEE
ence is not great. Coming to the other age groups between
the two extremes, there is a greater decrease in the degree of
stretching in the forehead than the forearm in each corresponding age group.
Microscopic emmirzations
The microscopic study was done only on the dermis, which
is divided into a superficial subepidermal layer and a deep
reticular layer. The thickness of the dermis was measured
with a micrometer, starting at the junction of the epidermis
and dermis, at the base of the dermal papillae, and ending at
the junction of dermis with the subcutaneous fat. The sections
were considered perpendicular to the surface by the appearance of the epidermis. The mean of 10 measurements was
recorded for each specimen (table 1).
Ski% of the forearm: The dermis is thin in the young age
group. Under 10 years, it varies from 0.56 to 0.90mm. The
dermis increases markedly in thickness in teen-age groups
and in people in their twenties and thirties, varying from
1.15 to 1.82mm. It tends to become thinner again in the
forties, and the measurements show a definite thinning of the
dermis from 50 years onward. The lowest measurement in
my series is that of the 84 year old specimen, it measures
only 0.46mm. Therefore the change in dermal thickness of
the forearm from people of different ages follows a similar
pattern as the change in degree of stretching: low values
observed in the very young and very old, and higher values
in the middle ranges (fig. 4). The coefficient of correlation
between age and thickness of dermis of the forearm was also
calculated, r=0.82 for people under 20, and r=-0.73
for
people over 20 years of age. It seems that females tend to
have a thinner dermis especially after attaining adulthood.
I n the subepidermal elastic plexus, the elastic fibers are
very fine and lie in various directions. Sometimes they are
diffusely scattered, sometimes they become condensed to a
very thin membrane-like layer, which lies a little distance
481
AGE CHANGES IN HUMAN SKIN
below and parallel to the basement membrane of the epidermis. Fine straight elastic fibers extend up into the dermal
papillae in a flame-like fashion. No apparent age difference
was observed in the subepidermal plexus of elastic fibers. I n
the reticular layer of the dermis, the elastic fibers are thicker
and more robust, running in all directions, interlacing with
each other, and mingling with bundles of collagenous fibers.
The elastic fibers form a thin envelope for the sweat glands
Male
0 Female
I .oo
0
0
20
40
60
L3
Age in years
Fig. 4 Thickness of dermis of the forearm skin in different age groups. The
subjects are arbitrarily divided at 20 years of age in the regression lines which
are plotted.
immediately outside the basement membrane, It starts to
appear around the age of 6 years and is defhitely absent nnder
5 ; and it seems slightly thicker in people over 65 than in
younger adults. No such intimate relationship between elastic
fibers and hair follicles o r sebaceous glands can be seen. The
relative amount of elastic tissue, or the absolute amount in a
given area, i.e., the density, is high in the age group below
10, but decreases very markedly in the teen-age group and
in the twenties and thirties; it varies a little in people of 40
to 60, but becomes high again after 60. The absolute amount
482
MARJORIE M. C. LEE
of elastic fibers is difficult to estimate, because of the difference in thickness of the dermis in the different age groups.
It appears that in teenagers and young adults, while the skin
stretches more and the dermis is thick, it contains the lowest
density of elastic fibers; in both the extreme age groups, the
skin stretches less, and the dermis is thin, but it contains a
high density of elastic fibers. Besides the differences in relative quantity of elastic tissue in the dermis of different ages,
no apparent change in the nature of the elastic tissue with
age can be observed ; the appearance of the elastic fibers seems
quite consistent in all the specimens. No sexual difference
was recognized. The structure of sweat glands, hair follicles,
and sebaceous glands show no degenerative change with advancing age (figs. 5-10).
81& of the forehead: the thickness of the dermis of the
forehead as measured under the microscope does not show as
systematic a change as that of the forearm. The thickness of
the skin of the forehead and forearm is almost equal in the
individuals below 10; in the young adults the forehead skin
also tends to increase a little in thickness but to a lesser extent
than that of the forearm; after the forties, the skin of the
forehead tends to be thicker than that of the forearm, especially in males (table 1). Further examination of the dermis
under the microscope reveals that the greater thickness of the
forehead skin after the forties is due to hypertrophy and
hyperplasia of the sebaceous glands, which form a special
stratum by themselves in the deeper part of the reticular layer
of the dermis. If this layer of sebaceous glands were excluded,
the measurement of the dermal thickness would be reduced
to less than half of the recorded reading. Hypertrophy and
hyperplasia of the sebaceous glands are a very constant finding in my series of 13 specimens over 40 years of age, but they
occur only in the 9 males; the 4 females in this age group do
not show this feature (figs. 13-15).
The elastic tissue in the subepidermal layer of the dermis
consists of fine fibers arranged as in the forearm. There is
no obvious age change in it except that in certain areas in the
AGE CHANGES IN HUMAN SKIN
483
older groups the subepidermal plexus may become so thin
that it merges with the superficial part of the reticular layer.
The reticular layer of the dermis also consists of many thick
and robust elastic fibers; there is no obvious change in the
amount of them in children and young adults (figs. 11, 12).
There is a definite change in appearance of elastic fibers in
the forehead of the older subjects: in the superficial part of
the reticular layer of the dermis, the elastic fibers may increase greatly in thickness, and apparently also in amount,
and they tend to become matted together to form a localized
mass of elastic tissue, so that in the superficial part of the
dermis the homogeneous appearance is lost; one may see a
local aggregation of matted elastic tissue masses with areas
of fewer elastic fibers intervening (figs. 13-15). This change
shows a little individual variation; it may start with slight
changes in some subjects in the thirties, others may not show
any change even in their fifties, but it occurs quite constantly
from age 60 onward. The deeper part of the dermis of the
forehead does not show obvious changes in the elastic fibers
with age.
The sweat glands, hair follicles, and sebaceous glands in
the forehead are much more abundant than in the forearm.
There seems to be no difference in the integrity and amount
of sweat glands in young or old, except that in children under
8, there is no thin elastic investment around the sweat glands
such as occurs in the forearm.
DISCUSSION AND CONCLUSIONS
Regarding the age change in the elastic tissue of the unexposed skin, Dick (’47) found a similar result in his series of
unexposed skin of the limbs and trunk: “the quantity and
arrangement of elastic tissue was very similar in the individuals under 5 years and over 65 years of age, in the age
group from 15 to 23 years of age the elastic fibers are large
and well formed but fewer than in early life.” Ma and Cowdry
(’50) found a decrease in elastic tissue in the antecubital region in the group of individuals from 78 to 94 years of age,
484
MARJORIE M. C. LEE
an age group older than that studied by either Dick or the
present writer. Beside changes in amount (or density) of
the elastic fibers with age, other “senile degenerative changes”
have been described by Ejiri (’38) as the appearance of fine
and coarse granules of elastic tissue, and by Dick (’47) as
irregular fragmentation of the ends and as variety in length
of the elastic fibers; such appearances, however, could have
been produced by the different directions of the components of
the elastic tissue meshwork being sectioned. Changes of that
kind were not appreciated in my specimens. There is not much
disagreement about the changes in appearance of the elastic
tissue of the exposed skin in the older individualms, such as
increase in thickness and amount, and condensation to form
irregular masses over the superficial part of the dermis. The
difference in elastic tissue reaction in the exposed and unexposed area of senile skin implies that the change in appearance of the elastic tissue is actually caused by rigors of the
external environment rather than by advancing age itself.
The degree of linear stretch of the forearm skin responding
to a small weight (10 gm) shows an inverse relationship t o
the density of the elastic fibers in the dermis: the higher the
relative amount of the elastic fibers, the less the skin stretches
and vice versa. This holds true and is easily appreciated in
the walls of the arteries: the big elastic arteries, with a tremendous amount of thick elastic laminae in their walls, can
stand a much greater pressure in the lumen; in other words,
they require a greater force to expand them, or to lengthen
the elastic fibers in them; while in the smaller arteries, the
elastic content becomes much reduced and the pressure required to expand them to the same extent as the large elastic
arteries is much lower. As in the case of the skin specimens,
if the force is the same, the less elastic artery will expand
more than the heavy elastic artery. I n the forehead skin, the
increased amount of matted elastic tissue of old people coincides with a decrease of stretching. Although the stretching
of forehead skin tends to decrease with age, no marked difference in the elastic fibers of the forehead skin in young adults
AGE CHANQES I N HUMAN SKIN
485
and children was observed, perhaps because the method used
to determine the density of elastic tissue by visual estimation
alone does not permit appreciation of slight changes.
Many authors have suggested a role for elastic fibers in the
skin. White ( Y O ) considers elastic tissue as a regulator of
the skin, counteracting torsion, stretching, and pressure of
the integument. Steinberg ('25) believes that elastic fibers
being rigid prevent overdistension of the skin. Lynch ('34)
thinks that the original conception of the function of elastic
fibers as an elastic framework for the skin is undergoing
change, and that the elastic system acts as a more or less
rigid framework for the attachment of the muscular system
of the skin. Xacleod and Muende ('40) stated that the elastic
fibers are not so extensile and retractile as the name implies,
they form a scaffolding or skeletal supporting and holding
together various elements of the corium and subcutaneous
tissue. Lever ('54) thinks the elastic fibers are rigid, not
elastic, but because of their rigidity, they effect the return of
the skin into its normal position after stretching. Actually
the role of elastic fibers in other organs such as in the media
of the arteries, adventitia of the veins, the respiratory tract,
ligamentum flavum, and even in the matrix of the elastic
cartilages is not different from that in the skin: being elastic
they stretch proportionally to the amount of force applied,
and recoil after the force is removed; and at the same time,
being firm and rigid, they also give support to the organ in
which they are imbedded. Therefore it is not justified to
emphasize the supporting function of the elastic fibers in the
skin, but not to credit their elasticity; while in the other organs, as in the vascular system and the respiratory tract, their
elastic property has been considered solely, but the supporting
function has often been neglected.
I n the forearm skin, the thickness of the dermis shows a
clear relationship with age similar to that of stretching. The
dermis of the forearm region contains very few hair follicles,
sebaceous and sweat glands and is mainly made up of a
collagenous fiber network, so that the degree of stretching of
486
MARJORIE M. C. LEE
the forearm skin seems proportional to the amount of collagenous fibers in the dermis. The collagenous fibers in the
dermis are wavy bundles arranged in various directions. Application of a light weight (10 gm)can tend only to straighten
out the bundle of collagenous fibers, probably not to extend
the fibers themselves. The coefficient of correlation of the
dermal thickness to the degree of stretching of the forearm
skin was calculated independently from the age factor; it
shows a low correlation, r =0.34. To the extent of the correlation, however, we may say that there is a tendency for the
bundles of collagenous fibers to be more wavy and/or more
obliquely set in the thicker dermis, thereby allowing greater
stretching.
The relationship of dermal thickness to stretching of the
forehead skin cannot be clearly seen, owing to the high content of hair follicles, sebaceous and sweat glands in it, especially the hypertrophy of sebaceous glands as occurs in older
men. Ronchese ('46) and Epstein ('46) both say that the
sebaceous and sweat glands become atrophic and decrease in
number in the senile, but neither refers to a specific site. I n
my series of forearm skin, no apparent change can be observed in either sweat or sebaceous glands. Way ('31) also
described hypertrophy of senile sebaceous glands of the forehead and other parts of the face, in persons past the fourth
decade, but does not mention the sex of his cases.
Although they look different grossly, microscopically the
structure of the dermis of the forearm of the children and
senile people is quite similar ;therefore no simple relationship
between the gross appearance of the skin and the structure
of the dermis can be drawn. F o r the skin of the forehead, the
degree of the change in appearance of the elastic tissue does
not seem to show direct correspondence to the gross appearance of the skin.
SUMMARY
1. Thirty-five specimens of unexposed skin (forearm) and
26 specimens of exposed skin (forehead) of both sexes from
early infancy to 84 years of age were taken at necropsies.
AGE CHANQES I N HUMAN SKIN
487
2. The degree of stretch and recoil of these specimens was
tested : the forearm skin stretches less in childhood and in old
age, and more in teenage groups and young adults; in the
forehead the degree of stretch decreases steadily with advancing age.
3. Microscopic examination of the forearm skin reveals a
thin dermis in children and old people, and a thick dermis in
teenage groups and young adults, whereas the density of
elastic fibers shows an inverse relation to the dermal thickness.
The role of stretching of skin with respect to dermal characteristics is discussed. Microscopic examination of the forehead skin shows change in appearance of the elastic tissue in
the superficial part of the dermis in the older people. Thinning
of the dermis in old age is concealed by hypertrophy and hyperplasia of the sebaceous glands, probably only in males,
however.
ACKNOWLEDGMENTS
The author thanks Professor F. K. S. Chang and Mr. R. B.
Maneely of the Department of Anatomy, University of Hong
Kong for their encouragement and help. Drs. E. Gardner and
R. O’Rahilly of Wayne State University kindly read and
criticized the manuscript, and Dr. G. W. Lasker, also of Wayne
State University aided the author with the statistical analysis.
LITERATURE CITED
DICK,J. C. 1947 Observations on the elastic tissue of the skin with a note on
the reticular layer at the junction of the dermis and epidermis. J. h a t . ,
81: 201-211.
1951 The tension and resistance to stretching of human skin and
other membranes with results from a series of normal and oedematous
cases. J. Physiol., 212: 102-113.
EJIFS, I. 1938 Histology of the human skin: 11. On differences in the e h t i c
fibers of the skin according t o sex and age. Abs. in Arch. Dermat. and
Syph., 97 :664.
1938 Histologic studies of human skin: 111. Changes according to
region and to age, of different elements of the skin, with particular consideration of changes of elastic fibers with age. Ibid., 87: 666.
488
MARJORIE M. C. LEE
EPSTEIN, S. 1946 Dermatitis in the aged. Geriatrics, I: 369-383.
EVANS,R., E. V. COWDRYAND P. G. NIELSON1943 Age of human skin. Anat.
Rec., 86: 545-565.
HILL, R., AND H. MONTGOMERY
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PLATES
PLATE 1
EXPLANATION OF FIGURES
Skin of forearm showing thickness of dermis and density of elastic tissue.
Stained with alcoholic orcein. X 60.
5 one year old female.
6 4 year old female.
7 27 year old male.
8 35 year old male.
9 73 year old female.
10 84 year old male.
PLATE
491
1
PLATE 2
EXPLANATION OF FIGURES
Skin of forehead, showing thickness of dermis and changes in elastic tissuc in
tliu superficial part of t h r dermis. Notice hypertrophy and hyperplasia of the
sebaceous glands in males over 40 years of age (figs. 13 and 15). Stained with
nleoholic orcvin. x 60.
14 73 year old female.
15 84 year old male.
11 5 month old female.
12 15 year old male.
13 65 year old male.
492
AGE C H A N G E S 1 N HUMAN S K I N
M.1RJORIE 21. 0 . LEE
493
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