Anatomical study of the seminal vesicle system for transurethral seminal vesiculoscopy.

Because of a general lack of knowledge regarding the precise anatomy of the seminal vesicle system, efforts to use transurethral seminal vesiculoscopy (TSV) are currently constrained. We investigated 26 normal adult male specimens. Contrast medium was injected into the seminal vesicle system in 18 specimens and the openings of the ejaculatory ducts were examined with an operating microscope. India ink was injected into the urethra in four specimens to investigate the function of the ejaculatory duct valve. Another four specimens were examined histologically to identify the anatomical relationships of the seminal vesicle system. We found that the openings of the ejaculatory ducts were covered by the ejaculatory duct valve, which could be classified into two types and acted as a one-way valve. The apex of the seminal colliculus together with the right and left openings of the ejaculatory ducts formed a shape resembling an isosceles triangle. This could be used to locate the openings of the ejaculatory ducts during TSV. The ejaculatory ducts can be classified into two types according to their course. During surgery, efforts must be made to protect the ejaculatory duct valve. During inspection or surgery, the second segment and the angles of the ejaculatory ducts, particularly in Type Ib and Type II cases, require particular attention. Clin. Anat. 32:244-252, 2019.