Due to weakening of the linea alba( fascia that lies between the rectus abdominis muscles and keeps them in close proximity)
Risk factors include chronic abdominal stretching (eg, pregnancy, multiparity), surgical weakening (eg, prior cesarean deliveries), and increased intraabdominal pressure (eg, constipation)—all of which weaken the linea alba.
As the linea alba weakens, abdominal contents bulge between the rectus abdominis muscles (especially with Valsalva), resulting in a nontender midline mass.
diagnosis can typically be made clinically.
Unlike a true hernia, rectus abdominis diastasis has no associated fascial defect, and patients have no associated pain, acute gastrointestinal symptoms, or risk of bowel strangulation or incarceration.
Therefore, patients are managed conservatively with observation and reassurance. Rectus abdominis diastasis typically resolves postpartum; surgery is typically reserved for cosmetic reasons in patients whose diastasis does not resolve.
(Choice B) Immediate surgical repair is indicated for hernias complicated by strangulation or incarceration. This patient has no fascial defect and a nonacute abdomen (ie, no rebound or guarding), making this diagnosis unlikely.
(Choice C) MRI can be used to identify unclear anterior wall defects and associated structures. The diagnosis of rectus abdominis diastasis can typically be made clinically.