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Vesicular duct
Last reviewed: 19.11.2021
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The ductus deferens (ductus deferens), a paired organ, is a direct extension of the duct of the epididymis and terminates at the fusion site with the in vivo duct of the seminal vesicle. The length of the vas deferens about 50 cm, the diameter is about 3 mm, and the diameter of the lumen does not exceed 0.5 mm. The wall of the duct is of considerable thickness, so it does not subside and is easily probed in the spermatic cord.
Based on the topographical features of the vas deferens, four parts are distinguished in it. The initial, shortest section behind the testicle, medial to its epididymis, is called the ovarian part. The next part, rising vertically upwards, passes through the spermatic cord, medially from its vessels, and reaches the superficial inguinal ring - this is the cord. Further, the vas deferens enter the inguinal canal, where its inguinal part is located. Leaving the inguinal canal through a deep inguinal ring, the vas deferens along the side wall of the pelvis down and back to the confluence with the excretory duct of the seminal vesicle. This section of the vas deferens was called the pelvic part. In the cavity of the small pelvis, the duct is under the peritoneum (retroperitoneally). On his way he bends from the lateral side of the trunk of the lower epigastric artery, crosses with the external iliac artery and vein, penetrates between the bladder and rectum, crosses the ureter, reaches the bottom of the bladder and approaches the base of the prostate, next to the same duct of the opposite side . This terminal section of the vas deferens is enlarged, fusiform and forms an ampulla of the vas deferens (ampulla ductus deferentis). The length of the ampoule is 3-4 cm, its largest transverse dimension reaches 1 cm. In the lower part of the ampoule it gradually narrows and, entering the thickness of the prostate gland, joins the duct of the seminal vesicle.
The wall of the vas deferens consists of the mucosa, the muscular and the adventitial membranes. The mucosa (tunica mucosa) forms 3-5 longitudinal folds. In the area of the vas deferens, the mucosa has bayonet protrusions - diverticulum ampullae (diverticulum ampullae). Outside the mucosa is the muscularis (tunica muscularis). It consists of obliquely oriented middle circular, inner and outer longitudinal layers of undistorted (smooth muscle cells). The muscular membrane gives the wall of the vas deferens almost cartilaginous density. In the ampulla of the vas deferens muscle layers are less pronounced.
Outside, the wall of the vas deferens is represented by the adventitial tunica (tunica adventitia), which without sharp boundaries passes into the surrounding duct connective tissue.