There are a variety of variants of normal skin structure e.g. with site on body, race, age, etc. which should be considered during examination:
- colour: varies with melanocyte density, concentration of pigment, blood flow etc.
- thickness: thick skin e.g. upper portion of back; different from the histological definition of thick skin based on epidermal thickness
- density of hairs per unit surface area: certain areas are hairless e.g. palmar surface of hand and plantar surface of foot
- distribution of hairs: difference between the sexes, dependent on hormonal exposure and response
- skin creases:
- joint creases: where skin is more adherent to deeper tissue
- wrinkle lines: caused by muscle contraction deep to skin and perpendicular to the long axis of the muscle
- contour lines: lines demarcating the junction of body planes e.g. the nasolabial fold
- lines of dependency: due to the effect of gravity on loose skin and fatty tissue with age e.g. the folds delimiting facial jowls
- cleavage lines: Langer's lines following the path of subcutaneous fibrous bundles
- existing scars: stage of repair, hypertrophic or keloid
- blood supply: colour, temperature, capillary refill
- dermal ridges: 'fingerprints'; role in gripping and texture recognition
- sweat glands: density and activity
- sebaceous glands: density and activity
- innervation: sensitivity to a given stimulus and variation across the body e.g. two-point discrimination tests for fine touch