Following tissue injury, whether healing occurs by regeneration or scarring is determined by the degree of tissue destruction, the capacity of the parenchymal cells to proliferate, and the degree of destruction of stromal framework
Wound contraction is a mechanical reduction in the size of the defect. The wound is reduced approximately by 70-80% of its original size. Contraction results in much faster healing, since only one-quarter to one-third of the amount of destroyed tissue has to be replaced. If contraction is prevented, healing is slow and a large ugly scar is formed.
Causes of contraction
It is said to be due to contraction by myofibroblasts. Myofibroblasts have the features intermediate between those of fibroblasts and smooth muscle cells. Two to three days after the injury they migrate into the wound and their active contraction decrease the size of the defect.