The rectus abdominis muscle is a paired muscle running vertically on each side of the anterior wall of the abdomen. There are two parallel sets of muscles, separated by a midline band of connective tissue called the linea alba (white line). It extends from the pubic symphysis/pubic crest inferiorly to the xiphisternum/xiphoid process and lower costal cartilages (5-7) superiorly. It is contained in the Rectus sheath. The rectus is usually crossed by three fibrous bands licked by the tendinous inscriptions. [WP,modified]. [ http://en.wikipedia.org/wiki/Rectus_abdominis_muscle ]