Umbilicus

Last revised by Craig Hacking on 28 Aug 2024

The umbilicus is the fibrous remnant of the fetal attachment of the umbilical cord after birth.

Gross anatomy

All layers of the anterior abdominal wall fuse at the umbilical ring, a small round defect in the linea alba located just inferior to the midpoint between the xiphoid process of the sternum and the pubic symphysis. The overlying skin is adherent to the umbilicus, causing a depression that is more accentuated with greater body mass.

The fibrous cicatrix is a fusion of several peritoneal and fibrous structures including the:

The umbilicus in the fetus transmits the umbilical arteries, umbilical vein, urachus
and the vitelline duct (in the first trimester). It closes a few days after birth and involutes.

Related pathology

  • umbilical hernia

  • omphalitis of the newborn due to infection of the stump of the umbilical cord

  • omphalitis in adults is rare and can be caused by infection of a urachal remnant, vitelline duct or foreign body