The Rectus Abdominis Muscle (the abdominal muscle) – anatomical notes
This muscle runs across the front of the abdominal wall from which follow, from front to back, the external, internal and transverse oblique muscles.
It extends from the upper pubic level and is attached at the xiphoid process of the sternum and the costal cartilages of ribs 5 to 7 of the rib cage.
In fact it is two muscles, right and left, connected by the linea alba (or midline), a thin band of connective tissue, without nerves and blood vessels, not particularly elastic but very resistant, which runs longitudinally between the two abdominal rectus muscles.
Diastasis recti, or diastasis of the abdominal muscles, is defined as a gap between the right and left abdominal muscles measuring at least 2,7 cm.
In pregnancy this is caused by an influx of hormones that encourages the stretching of the abdominal cavity to accomodate the growing uterus and in the case of low muscle tone of the core.
It is considered physiological if it is resolved within 12 months of giving birth.