ABSTRACT
The urachus is the fibrous remnant that represents the intraembryonic communication between the bladder and the allantois. The urachus closes by progressive accumulation of desquamated epithelium within the lumen early in gestation and becomes the median umbilical ligament. When this process has been disrupted, a patent urachus or urachal remnant will persist in the form of a cyst, sinus, or diverticulum (Figure 66.1). 1 A complete review of urachal anomalies can be found in Chapter 63.
