The ejaculatory duct is a tubular structure that joins the prostatic portion of the urethra and is responsible for transporting sperm and seminal vesicle fluid into the prostatic urethra, the final destination of sperm prior to ejaculation. A number of factors can cause obstruction of the ejaculatory duct and thus block the flow of sperm. These include problems such as congenital narrowing or scarring due to infection and compression due to a prostatic cyst or tumor.
Obstructed ejaculatory ducts are usually diagnosed by transrectal ultrasound imaging or by special radiographic tests called vasograms. Obstructed ducts are treated by a simple transurethral procedure whereby the obstructed part of the duct is removed, leaving normal, unobstructed ductal tissue behind.