Ejaculatory duct

The injection channel (also: " Spritzkanälchen " Latin ejaculatory duct ) is a paired -scale transition in mammals, which runs from the seminal vesicles also pairs created through the prostate and empties into the urethra. It carries the main part of the ejaculate in ejaculation.


Each ejaculatory duct is formed by the union of the equilateral vas deferens ( which comes from the epididymis ) and the excretory duct ( ductus excretorius ) of the equilateral seed bubble. In men, the injection channel is about 2 cm long.

The spray channel has no own muscular coat, only a mucosa, similar to the vas deferens. A lumen of more than 2.3 mm is not normal, but speaks for an enlargement ( dilatation). The anatomy is, for example, aligned by atrioventricular valves at the mouth of the urethra that a backflow of urine from the urethra is almost impossible in the seminal vesicles.

In some mammals no ejaculatory duct is formed: predators lack the seminal vesicles and, consequently, the excretory duct and thus the association with the vas deferens. In pigs and sheep remains under the union of the two transitions.

Longitudinal section of bladder, penis and urethra ( urethra )

Prostate with seminal vesicles and vas deferens, view from the front and top


The closure of the ejaculatory duct is a congenital or acquired disease, in which one or both ejaculatory ducts are closed or narrowed. If both ejaculatory ducts are closed, the affected man is infertile due to a lock - azoospermia. If this condition is treated surgically by a transurethral resection of the ejaculatory duct ( tured ), it comes to removal of the atrioventricular valves and in the seminal vesicles flowing back urine can degrade the quality of seeds. In addition, the urine can now access via the vas deferens to the epididymis and may lead here to a epididymal inflammation caused by bacteria from the urethra.

The surgical treatment of benign prostatic hyperplasia may infringe or close the spray channels.

In retrograde ejaculation, the semen coming from the Spritzkanälchen then flows within the urethra not towards penis off, but in the wrong direction: into the bladder.