The linea alba is a longitudinal, fibrous median raphe along the rectus sheath formed by the fusion of the anterior and posterior walls of the sheath. It may be visible as a surface marking on individuals with well-developed abdominal musculature running as a depression between the xiphoid process of the sternum and the pubic area.

It separates the two parts of the rectus abdominis muscle which lie laterally. It is traversed by the umbilicus. It may be visible as a surface marking on individuals with well-developed abdominal musculature.