ABSTRACT
Arcuate uterus with a rudimentary uterine horn develops from incomplete atresia of one of the two müllerian ducts during embryogenesis. The rudimentary horn can have a cavity (cavitated) or be noncavitated, and the cavity could be communicating or not communicating with the uterine cavity of the arcuate uterus. In most cases, there is no communication between the uterine cavity proper and the cavity of the rudimentary horn (Figure 20.1). As a result, menstrual blood will accumulate in the rudimentary horn (hematometra), causing cyclic abdominal pain. This also predisposes to the development of endometriosis. The rudimentary horn may be separated from the unicornuate uterus with fibrous tissue or adherent to it.
