Umbilicus

Author: Sophie Stewart • Reviewer: Dimitrios Mytilinaios MD, PhD
Last reviewed: November 10, 2022
Reading time: 2 minutes

Umbilicus

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Synonyms: Navel

The umbilicus forms the fibrous remnant of the umbilical cord. 

During embryonic development, the umbilical cord acts as a conduit between mother and baby and creates a channel which allows blood to flow between the placenta and fetus. After birth, the umbilical cord detaches and a fibrous scar, the umbilicus, remains. The umbilicus contains the obliterated orifices of the three umbilical vessels (one vein, two arteries)

The layers of the anterior abdominal wall fuse at the umbilical ring (final part of the abdomen to close during development) which surrounds the umbilicus. The umbilicus is located along the midline of the anterior abdominal wall at the level of the intervertebral discs between L3 and L4. 

The umbilicus is composed of four parts/structures: the mamelon, cicatrix, cushion and furrows.

The mamelon is the area of the central hump of the umbilicus. The cicatrix forms the dense scar and is a fusion of several peritoneal and fibrous structures (round ligament of liver, median umbilical ligament, two medial umbilical ligaments, transversalis fascia, umbilical fascia and parietal peritoneum). The cushion of the umbilicus is the slightly raised skin margin which surrounds the mamelon and cicatrix. Finally, the furrows forms the depression inside the cushion, surrounding the mamelon.

The umbilicus acts as an important anatomical landmark of the abdomen as its position is relatively consistent between individuals. It is also used to separate the abdomen into quadrants and regions. 

Take a closer look at the surface anatomy and regions of the abdomen with the study unit below: