High‐frequency ultrasound characterization of normal skin. Skin thickness and echographic density of 22 anatomical sites

Abstract

Variation in skin thickness relative to anatomical site was little studied in the past. Biopsy cutting and histological processing change tissue geometry. High-frequency ultrasound allows in vivo measurement of skin thickness of multiple sites. The object was to map regional differences in skin thickness. 22 different anatomical sites were studied. The Dermascan C (20 MHz) was used. The acoustic density of the dermis and the epidermal entrance echo was analyzed by the in-built image analysis software. 18 healthy volunteers aged 24-41 years were studied. Extremity skin was thinner than truncal skin, and acoustically dense. Females had thinner and more dense skin in comparison with males. Skin of the palm, sole and the head was thick but weak in density, and the biological variation in the dermis/subcutaneous tissue interphase does not allow highly accurate evaluation in these special sites. There was an overall inverse correlation between skin thickness and acoustic density with thin skin being dense and thick skin being relatively echo-poor. Skin thickness and acoustic density reflecting intradermal structure exhibit systematic regional variation with thin and dense skin on extremities in comparison with the trunk and special ultrasound profiles in selected sites such as the face, the palp and sole. Female skin is thinner and more dense in comparison with male skin.