The linea alba is a tendinous raphe extending from the xiphoid process to the symphysis pubis and pubic crest. It lies between the two recti and is formed by the interlacing and decussating aponeurotic fibers of external oblique, internal oblique and transversus abdominis. It is visible only in the lean and muscular, as a slight groove in the anterior abdominal wall.
The umbilicus, lies a little below the midpoint of the linea alba, and is covered by an adherent area of skin. Below the umbilicus, the linea alba narrows progressively as the rectus muscles lie closer together. Above the umbilicus, the rectus muscles diverge from one other and the linea alba is correspondingly broader.
The linea alba has two attachments at its lower end: its superficial fibers are attached to the symphysis pubis, and its deeper fibres form a triangular lamella that is attached behind rectus abdominis to the posterior surface of the pubic crest on each side. This posterior attachment of linea alba is named the ‘adminiculum lineae albae’. The linea alba is crossed from side to side by a few minute vessels.