How thick is human skin at the wrist (either top, bottom, or both) and
at the forearm?

---

Request for Question Clarification by feilong-ga on 15 May 2003 11:27 PDT

I haven't seen a definitive answer yet but from what I've seen so far
from my initial search is that human skin varies in thickness from one
person to person by a fraction or a few millimeters. Age is also a
factor. Given these, could you give us a specific description if
possible?

---

Clarification of Question by svdh-ga on 15 May 2003 12:02 PDT

Age range of an individual is 30 years and up.  I would be interested
in differences between sex as well, so any information on that would
be acceptable.  Any breakdown by ethnicity would also be useful, but
not necessary.

---

Request for Question Clarification by answerguru-ga on 15 May 2003 13:42 PDT

Hi there,

It doesn't appear that skinfold measurements are commonly done at the
wrist, but if you would like I can provide statistics with charts and
raw data for the triceps and subscapular (back) skinfold sizes (broken
down by age and gender). It is worth mentioning that by taking a
measurement of a collection of skinfolds, you will be able to more
effectively assess fitness levels and so forth.

Looking forward to hearing from you :) 

answerguru-ga

---

Clarification of Question by svdh-ga on 15 May 2003 14:11 PDT

While skinfold thickness measurements may be useful as body fat or
fitness indicators, I am looking for something more specific to skin
at the wrist or forearm.  You may consider looking in the forensic
literature, especially something called the Manchester Protocol or in
the anthropologic forensic area where skin depths are supposedly known
for various ethnicities and ages and allow for reconstruction of faces
from skulls.  There may be something in that field pertaining to skin
depths elsewhere on the body.  But, to emphasize again, I am looking
specifically for numbers describing skin thickness in the forearm or
wrist area.  Thank you.

Standard skin thickness measurements are for the thickness of the
epidermis and dermis these layers are firmly adherent between the
papillary layer of the dermis and strum germinativum of the epidermis.
The thickness varies from 0.5 – 4mm. Skin is generally divided in
terms of thickness into thin skin and thick skin. Thick skin is found
on the palms of the hand and soles of the feet (4mm) with thin skin
covering the remainder of the body, thinnest skin is eyelid 0.5 mm.
The variations in think skin within the body are due almost entirely
to the variation in thickness of the dermis with the dermis of the
extensor surfaces (back of the forearm – posterior surface) generally
being thicker than the flexor surfaces (front of the forearm anterior
surface).

The thickness of the skin used to be measured optically but more
commonly it is now measured using ultrasound. Skin varies in thickness
especially with different clinical conditions i.e. Acromegaly where
the skin is thickened or the application of topical (applied to the
surface) steroids which tend to lead to reduce skin thickness.

Changes with age
The skin at birth is relatively thin and easily damaged
Growth and repair during life  - “The growth of the skin adjusts
itself to the varying surface area of the adult body. If there is
rapid and considerable gain in weight, the skin grows to cover the
increased volume. Sometimes the volume may increase so rapidly that
the skin cannot keep pace; for example, in pregnancy some areas of the
skin on the abdominal wall may become stretched and thinned, so giving
rise to the characteristic thin shiny patches known as striae
gravidarium.
When weight is lost in adult life the elasticity of the skin adjusts
it to the lessened surface area, and skin growth becomes
correspondingly depressed to keep pace with the needs of the body. If
the loss of weight occurs after the elastic fibres have degenerated in
old age, the stretched skin hangs loose wrinkles over the reduced body
surface.” Sinclair D 1975

This is particularly important in modern medical techniques where if
extensive scarring occurs on a part of the body an inflatable device
is inserted under the skin and inflated with air or saline over a
period of time until the skin has grown to a sufficient extent when
the scarring is excised and the new skin used to cover the cosmetic
deformity.

The change with age can be seen using the skin pinch test on the back
of your hand if you pinch an amount of skin and then let go depending
on your age it returns to normal the older the longer it takes. Slide
47 http;//www.cladonia.co.uk/biology/ageing.htm

Skin can also change following injury becoming thinner after the
injury or with some people hypertrophic. Some races especially African
are more susceptible to develop hypertrophic scarring or what are
called keloid scars, but they may occur in anyone.

Measuring the thickness of skin at the wrist is a common area for
looking at the effect of treatments creams etc used in dermatology.
The reference below will give the nearest measurements to the back of
the forearm.

Medline 
 Fornage BD.  Deshayes JL.  Ultrasound of normal skin.  Journal of
Clinical Ultrasound.  14(8):619-22, 1986 Oct.
Abstract
  The authors have used a commercially available real-time sector
scanner and a 10-MHz probe with a built-in water path for B-mode
imaging of the normal skin. Measurements have been performed in 10
volunteers at 18 sites on the body surface. Normal skin thickness
ranges from 1.4 mm at the dorsal aspect of hand to 4.8 mm at the heel.
Clinical applications of B-mode imaging of the skin are discussed.

References Leeson and Leeson. Histology. Philadelphia: WB Saunders.
2nd edition 1970.
Sinclair D. Human Growth after Birth. Oxford: Oxford University Press,
2nd edition 1975.

Web resources on skin http://dermis.net/index_e.htm
Information on effect of different diseases on skin thickness 
... of cutaneous oedema in patch test reactions my measurement of skin
thickness with ... at 24-h increases from the antecubital fossa to the
wrist : an echographic ...
bioeng.psu.edu/labs/NIH/derm_app.pdf