Rectus Abdominis Muscle

Rectus Abdominis Muscle

The rectus abdominis muscle, also known as "abs" or a "six pack", is a paired muscle running vertically on each side of the anterior wall of the human abdomen (and in some other animals). There are two parallel muscles, separated by a midline band of connective tissue called the linea alba (white line). It extends from the pubic symphysis, pubic crest and pubic tubercle inferiorly to the xiphoid process and costal cartilages of ribs V to VII superiorly.

It is contained in the rectus sheath, consisting of the aponeuroses of the lateral abdominal muscles.

The rectus is crossed by three (rarely four) fibrous bands called the tendinous intersections. This causes the formation of six muscle bellies, giving rise to its common name as the "six-pack."