normal gross morphology

Last reviewed 01/2018

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