Vas deferens

Eva Rudolf-Müller is a freelance writer in the medical team. She studied human medicine and newspaper sciences and has repeatedly worked in both areas - as a doctor in the clinic, as a reviewer, and as a medical journalist for various specialist journals. She is currently working in online journalism, where a wide range of medicine is offered to everyone.

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The spermatic duct (ductus deferens or vas deferens) is the duct of the epididymis. In it, the sperm that mature and are stored in the epididymal duct (ductus epididymidis) are transported on until they are thrown out of the urinary tube together with the secretion of the seminal vesicle and the prostate during ejaculation. Read everything you need to know about the vas deferens!

What is the spermatic duct?

The right and left vas deferens (singular: Ductus deferens or Vas deferens) are each 50 to 60 centimeters long and about half a centimeter in diameter, which connect the testicles / epididymis with the urinary tube. Each spermatic duct begins at the lower end of the epididymis, in the area of ​​which it is so twisted that its length to the mouth is only about 35 centimeters.

What is the function of the spermatic duct?

The ductus deferens is a transport organ. He can suck the semen in the epididymis (where they are stored for about twelve days) using a suction pump mechanism and then empty them into the urinary tube using a pressure pump mechanism.

This mechanism is made possible by the arrangement of smooth muscles in the wall of the two vas deferens: on the outside there is a longitudinal, in the middle a ring and inside again a longitudinal muscle layer, which are arranged in a spiral system.

Thanks to this strong muscular wall, the diameter of the spermatic duct can be reduced in the area in which it joins the duct of the seminal vesicle. This reduction in the inner diameter creates the high pressure and the high speed with which the seminal fluid is transported into the urinary tube and further outwards during ejaculation.

Where is the spermatic duct located?

The right vas deferens leads from the right epididymis, the left ductus deferens from the left epididymis. With its vessels and its covering, the spermatic cord, each spermatic duct runs along the back of the epididymis up to the outer inguinal ring, where it enters the abdominal cavity.

Here, each vas deferens in front of the urinary bladder expands into an ampoule in which the sperm are stored. A little further on, the paired seminal vesicle opens into the vas deferens, which produces the liquid part of the ejaculate. Finally, the two vas deferens cross the prostate gland and open into the urethra. In the further course one speaks of the urinary tube.

What problems can the spermatic duct cause?

Some men have a congenital malformation in the area of ​​the vas deferens.

A small percentage of tumors in the scrotum (scrotum) are spermatic cord tumors, which are mostly benign (rhabdomyosarcomas). They mainly occur in childhood and adolescence.

Spermatic cord sarcomas, on the other hand, are malignant tumors that grow into the surrounding tissue (infiltration) and form daughter tumors (metastases).

A spermatocele is a fluid-filled cavity (cyst) that usually originates from the epididymis, less often from the spermatic cord. It arises at the upper testicle pole. To be precise, it is a so-called retention cyst, i.e. a cyst that is created by an obstruction to drainage. It is filled with semen and, if it grows larger than the head of a pin, it can cause a feeling of pressure.

External injuries can result in bleeding, bruising or an abscess (encapsulated collection of pus) in the area of ​​the ductus deferens.

As part of an inflammation of the prostate (prostatitis) or urinary tract infection, the paired vas deferens can also become inflamed.

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