The linea alba is a fibrous structure that runs down the midline of the abdomen in humans and other animals. The name means white line and the linea alba is indeed white, being composed mostly of shiny white collegen connective tissue.
It is formed by the fusion of the aponeuroses of the abdominal muscles, and it separates the left and right rectus abdominis muscles. In muscular individuals its presence can be seen on the skin, forming the depression between the left and right halves of a "six pack."
Because it consists of only connective tissue, and doesn't contain important nerves or blood vessels, a median incision through the linea alba is a common surgical approach.
