Fig. 1

Skin tension indices calculated from the skin topology images of the seven body areas (the forearm, the thigh, the cheek, the upper chest, the belly, and the anterior and posterior faces of the arm) for the young group (n = 21) and the elderly group (n = 21). (* for 0.01 < p-value < 0.05, ** for 0.001 < p-value < 0.01, *** for p-value < 0.0001, and – for p-value > 0.05).