Development of cleavage line patterns in the human fetus.
The dermal fibroelastic connective tissue of the fetus is arranged in such a manner as to represent cleavage lines (lines of tension). Cleavage lines were observed as early as the 28 mm stage but in most cases they do not appear until the 50 mm stage. The various regions of the body present individual cleavage line patterns which undergo alterations as the fetus grows. The pattern alterations are influenced by (1) rate of proportional growth and (2) principal direction of growth of certain structures in the various regions. The cleavage line pattern of the newborn differs from that of the adult in certain regions.
D003238:Connective Tissue / Q000196:embryology; D005260:Female; D005333:Fetus / Q000502:physiology; D006128:Growth; D006801:Humans; D011247:Pregnancy; D012867:Skin / Q000196:embryology*