The rectus abdominis muscle, also known as the "abdominals" 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. There are two parallel muscles, separated by a midline band of connective tissue called the linea alba. 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.The proximal attachments are the pubic crest and the pubic symphysis. It attaches distally at the costal cartilages of ribs 5-7 and the xiphoid process of the sternum.The rectus abdominis muscle is contained in the rectus sheath, which consists of the aponeuroses of the lateral abdominal muscles. Bands of connective tissue called the tendinous intersections traverse the rectus abdominus, which separates this parallel muscle into distinct muscle bellies. The outer, most lateral line, defining the "abs" is the linea semilunaris. In the abdomens of people with low body fat, these bellies can be viewed externally and are commonly referred to as "four", "six", "eight", or even "ten packs", depending on how many are visible; although six is the most common.Abs Workout:Bicycle-crunches Crunch-kicksLeg raisespulse-upsreverse crunchesscissorsarm / leg raisesHalf-wipersknee-in twistsplank rollswipersclimber taps....