Int J Leg Med (1992) 105:99-103 International Journal of Legal Medicine © Springer-Verlag 1992

Summary. Human skin wounds (66) inflicted between 20 h and 7 months prior to biopsy were studied. In order to identify the type of cellular differentiation of the fibroblastic ells in the granulation tissue, alpha-smooth muscle actin and desmin were immunohistochemically localized. The value of any presumed time-dependent appearance and/or disappearance of positively stained cells was tested for the estimation of wound age. In skin specimens with a wound age less than 5 days (n = 15) no typical granulation tissue had developed and o alpha-actin-positive myofibroblasts could be detected. The first appearance of positively reacting myofibroblasts was noted in a 5-day-old wound. In 57 % of the lesions with a wound age between 5 and 31 days (25 out of 44 cases) typical granulation tissue formation was presen