## 1 Introduction  
Diastasis of the rectus abdominis (DRA, diastasis recti, divariacation of the rectus abdominis, abdominal muscle separation) describes a condition in which an abnormally large distance separates the two rectus muscles [1]. These defects can range from a few millimeters to several centimeters and are often located between the xybroid and the umbilicus. In DRA, however, there is no facial defect and, therefore, no hernia. In adults, rectus diastasis occurs predominantly in two populations: peripartum middle-aged women (where the prevalence is up to 60% [2]) and older men. In women carrying a child, the occurrence of diastasis recti associated with the thinning and widening of the linea alba can be explained by an increase in intra-abdominal pressure and by the influence of the hormone relaxin. Despite a natural regression of the inter-rectus distance (IRD) in the postpartum period, physiotherapists recommend refraining from vigorous physical activity for at least 12 weeks after delivery because the abdominal wall may not have sufficient strength to withstand additional stress [3]. It has been observed that the occurrence of diastasis recti in infants is due to the immaturity of the abdominal wall. However, it can be postulated that diastasis recti may occur in children and adolescents when acute stress (recurrent cough due to pertussis, extreme exercise, etc.) is placed on a pre-weakened anterior abdominal wall (immutative tissues, after significant weight loss, obstipation, etc.). More research is needed on the prevalence and incidence of DRA in children. A deficiency of the abdominal wall maturation--especially in the Carnegie stadiums 19 to 20 (Day 46-49), where the four abdominal wall muscles develop--can lead to a congenital type of DRA [4]. This can occur with associated sequences or syndromes (such as prune belly syndrome, Beckwith-Wiedemann Syndrome, Cantrell pentagogy (thoracoabdominal syndrome), Opitz syndrome and midline defect syndrome) or through isolated autosomal dominant transmission [5]. Considering all pediatric patients, the prevalence of diastasis recti seems to be high, but there are no sources indicating the exact incidence of diastasis recti in children. The description of DRA in textbooks on the physical examination of the abdominal wall is: _\"Many normal infants have diastasis recti, resulting from the non-union of the two rectus muscles, which may result in an umbilical hernia.\"_[6], and _\"abdominal wall protrusions are common [in children]\"_[7]. This may be due to the immaturity of the abdominal wall with underdeveloped musculature and thin linea alba [8]. Considering that DRAs are frequently described in the literature and that surgical repair is not often mentioned, it must be admitted that most DRAs have a good prognosis and regress spontaneously, following a pattern similar to that of an umbilical hernia. The fascial opening of umbilical hernias closes spontaneously as the rectus abdominis muscles continue to grow towards each other, resulting in the fusion of the peritoneal and fascial layers around the umbilicus. Spontaneous closure is to be expected in almost all children at 5 years of age. Fascial openings greater than 1.5 cm, protruding skin, increased intra-abdominal pressure (from ascites or peritoneal dialysis) and underlying medical conditions (Ehlers-Danlos, Beckwith-Wiedemann syndrome, Down syndrome, mucopolysacharidoses, hypothyroidism or trisomy 18) may prevent spontaneous closure. As with many aesthetic or functional pathologies, the initial course of action is conservative, and surgical or interventional treatment should be carefully considered if a progression of the pathology is observed. [PERSON] [9] hypothesized that as the nervous system matures, the abdominal muscles move closer together, but in approximately 30% of all children the diastasis recti remains. She has developed a technique to reduce diastasis recti in children using an educational and playful concept called the Belly Button Program.