Latin anulus umbilicalis FMA 19930 | TA A04.5.01.023 | |
The umbilical ring is a dense fibrous ring surrounding the umbilicus at birth. At about the sixth week of embryological development, the midgut herniates through the umbilical ring; six weeks later it returns to the abdominal cavity and rotates around the superior mesenteric artery.
Dense embryonic connective tissue encircles the attachment of the cord. It forms an umbilical ring of mesodermal condensation surrounding the coelomic portal, and is present in the 16*1 mm. embryo, but more emphatically so in the 23 mm. embryo. The compact tissue first appears in the stalk mesoderm, situated superficial to the allantoic vessels. Cranially it lies ventral to the umbilical vein and on each side extends into the tissue of the lateral pillars of the cord bounding the coelom. When the myotomic downgrowths reach the ventral aspect their anterior portions, i.e. the sheaths of the recti muscles, become continuous with the tissue of the umbilical ring.