Rectus abdominis. The human rectus abdominis muscle. [edit on Wikidata] Example of a man with a visible rectus abdominis. The rectus abdominis muscle, also known as the “abdominal muscle” or “abs”, is a paired muscle running vertically on each side of the anterior wall of the human abdomen, as well as that of some other mammals.
Rectus abdominis. The rectus abdominis muscle is located in the front of the body, beginning at the pubic bone and ending at the sternum. It is located inside the abdominal region. The muscle is activated while doing crunches because it pulls the ribs and the pelvis in and curves the back.
The rectus abdominis is an important postural muscle. It is responsible for flexing the lumbar spine, as when doing a so-called “crunch” sit up.