abnormal Mullerian duct morphology Mullerian duct degeneration Muller duct degeneration paramesonephric duct degeneration MP:0006426 MPheno.ontology a retrogressive impairment of function or destruction of the transient embryonic drainage tubes of the embryonic kidney (mesonephric tubules) that empty into the cloaca and in the female develop into the oviducts, uterus, and vagina