Answer:
The origins of the rectus abdominis muscle are on the pubic bone.
Explanation:
The rectus abdominis (also known as L. rectus, straight) is a long, broad, strap-like muscle, which is the principal vertical muscle of the anterior abdominal wall.
It originates from the pubic symphysis and pubic crest.
The paired rectus muscles, separated by the linea alba, lie close together inferiorly. The rectus abdominis is three times as wide superiorly as inferiorly; it is broad and thin superiorly and narrow and thick inferiorly.
Most of the rectus abdominis is enclosed in the rectus sheath and the rectus muscle is anchored transversely by attachment to the anterior layer of the rectus sheath at three or more tendinous intersections.
The intersections, indicated by grooves in the skin between the muscular bulges, usually occur at the level of the xiphoid process, umbilicus, and halfway between these structures.
When tensed in muscular people, the areas of muscle between the tendinous intersections bulge outward.
Its main functions are to flex the trunk, compress abdominal viscera and stabilize tilt of the pelvis.
