Linearity and Surface Anatomy of the Face: From Embryo to Senescence

Curr Probl Dermatol. 2022;56:281-305. doi: 10.1159/000529557. Epub 2023 Jun 1.ABSTRACTFurrows, lines and wrinkles with distensibility and retractility are a biological need of skin in the service of skin integrity, plasticity and joint motion. The fundamental segmentation and linearity of skin is genetically coded, manifested early in embryonal life and remarkably constant throughout life. The basic pattern established early in embryonal life when facial segments expand and fuse is confounded by overlapping linearities of different backgrounds. Embryonal skin and skin in childhood, puberty, adult life and senescence undergo a general change in the direction of disturbed structure, nevertheless respecting the originally coded and segmented linearity. The fundamental linearity is expressed as the naso-frontal, maxillary and mandibular segments of the primitive face and the extremity buds forming extremities. The sensory nerves in this phase of morphogenesis follow and invade the segments of the face, trunk and extremities and form dermatomes,replicating the tissue segments. Early on, CREST cells migrate from behind, from the neural crest, and seed a normally hidden linearity in the tissues, which may appear as scleroderma lines, particularly the vertical "en coup de sabre" line(s) in the front. Later in pregnancy, during the phase of volume expansion, the resultant horizontal force applied to the outer skin results in gliding of epidermal structures relative to the underlying d...
Source: Current Problems in Dermatology - Category: Dermatology Authors: Source Type: research