"Striae" is also a general term referring to thin, narrow grooves or channels, or a thin line or band especially if several of them are parallel or close together.
Stretch marks, also known as striae, are a form of scarring on the skin with an off-color hue. Over time they may diminish, but will not disappear completely. Stretch marks form during rapid growth of the body, such as during puberty or pregnancy. In pregnancy they usually form during the last trimester, and usually on the belly, but also commonly occur on the breasts, thighs, hips, lower back and buttocks. These are known as striae gravidarum.
Stretch marks are caused by tearing of the dermis. This is often from the rapid stretching of the skin associated with rapid growth or rapid weight changes. Stretch marks may also be influenced by hormonal changes associated with puberty, pregnancy, bodybuilding, or hormone replacement therapy.
There is no evidence that creams used during pregnancy prevent stretch marks. Once they have formed there is no clearly effective treatment, though various methods have been attempted and studied.
Stretch marks they are usually seen in regions of the body that are known to be very susceptible to rapid increase in girth. The dermal layer of the skin is stretched out, making it appear cracked and torn. Stretch marks are usually caused by fluctuations in weight. This is why stretch marks appear during pregnancy. They are also seen in people who work out, because of the development of muscle mass and become apparent in dieters who have lost a lot of weight.