abnormal efferent ductules of testis morphology dilated efferent ductules of testis MPheno.ontology dilated efferent ducts efferent ductules of testis dilation an expansion in the volume or area of the lumen of the small seminal ducts that lead from the testis to the head of the epididymis, usually with an increase in contained fluid dilated vas efferens MP:0009140 dilated ductuli efferentes testis