Stretch marks are visible lines on the skin surface, with an off-color hue. Stretch marks are mainly found in the abdominal wall, but can also occur over the thighs, upper arms, buttocks and breasts.
Sometimes stretch marks can cover large areas of the body. While pregnancy is the main cause behind stretch marks, other reasons can be sudden gain or loss in weight, rapid growth, heredity factors, stress andchanges in physical conditions.
The skin consists of three main layers: Epidermis (the outer layer), Dermis (the middle layer) and Subcutaneous or Hypodermic (the deepest layer). Stretch marks form in the dermis or middle layer of the skin when the connective tissue is “stretched” beyond the power of its flexibility due to rapid expansion or contraction of the skin.