Vas Deferens

VAS DEFERENS (vas deferens, ductus deferens, ductus spermaticus) is formed from the Wolffian duct in the 3rd month of embryonic life. In its developed state, the vas deferens is a dense, cylindrical cord of uniform thickness, which is clearly palpable in the posterior sector of the spermatic cord. Anatomists divide the vas deferens into: 1) Pars testicularis, starting from the epididymis at the lower pole of the testis and ending at the point where the testicular membranes transition onto the spermatic cord. This part of the vas deferens, about 2.5 cm long, is located on the medial side of the epididymis and is very convoluted throughout its entire length. 2) Pars funicularis, representing a straight cord running within the thickness of the veins of the spermatic cord up to the inguinal canal. This part is the most accessible for palpation and can be isolated throughout its entire length. 3) Pars inguinalis—the part of the vas deferens from the external to the internal inguinal ring. Here, the vas deferens lies on the lower wall of the inguinal canal, medial to the vessels of the spermatic cord. 4) Pars pelvina—the pelvic part, which begins at the abdominal inguinal ring, runs medially under the peritoneum along the edge of the pelvis, heading posteriorly and inferiorly, crosses the ureter, and, being located medially to it, approaches the seminal vesicles under the bottom of the bladder, which lie laterally to it (see figure on p. 85). Here, the vas deferens widens slightly and forms the ampulla ductus deferentis; here also, at a distance of approximately 1–1.5 cm from the prostate gland, the ampulla of the vas deferens begins to narrow, receives the excretory duct of the seminal vesicle at an acute angle, and together with it forms a narrow duct again, which, under the name ductus ejaculatorius, penetrates the prostate gland and opens on the seminal colliculus. The total length of the vas deferens is from 40 to 50 cm (Eberth, Rauber), i.e., it is approximately equal to the length of the forearm and hand. Its thickness is uneven: in the initial part it is about 2 mm, then 6–7 mm in diameter; along the ampulla it reaches up to 1 cm, and finally the thickness decreases again to 3 mm. Corresponding to the diameter of the vas deferens, its lumen also varies, which constitutes approximately 1/8 of the thickness of the duct. In the inguinal part of the duct, according to Ingal, a needle 0.8–1.2 mm thick can be inserted into its lumen. The vas deferens, being located within the thickness of the spermatic cord, does not have a separate sheath and lies together with vessels and nerves, surrounded by a common vaginal tunic. Throughout the inguinal canal, the vas deferens is also covered by the common vaginal tunic, and upon entering the cavity of the lesser pelvis, it lies in the loose subperitoneal tissue, covered by the peritoneum and clearly visible through it. It is necessary to note that, while passing through the lesser pelvis, the vas deferens encounters a number of vessels and the ureter, which it bypasses and, by forming loops, becomes convoluted again. On its path, one encounters: the inferior epigastric arteries and veins, the external iliac arteries and veins, the obturator arteries and veins, the umbilical artery, the superior and middle vesical arteries and veins, and the ureter. The artery of the vas deferens originates from the inferior epigastric artery and is called the a. deferentialis. Descending along the vas deferens to the epididymis, the a. deferentialis joins the posterior branch of the testicular artery; in the upper section of the vas deferens, the a. deferentialis gives off a branch to the ampulla. In the case of the absence of the testicular artery, the only vessel supplying the testis is the a. deferentialis (Tikhomirov), which must be kept in mind during operations on the vas deferens. The vein of the vas deferens (v. deferentialis) collects blood from the epididymis, partially from the veins of the testis, anastomoses with the veins of the posterior bundle of the spermatic cord, in the pelvic region it forms a dense, looped network on the duct and ampulla, and drains into the vesico-prostatic plexus. The lymphatic vessels of the vas deferens are numerous, anastomose with the vessels of the spermatic cord, and drain into the hypogastric lymph nodes. Nerves...