This section is from the book "Applied Anatomy: The Construction Of The Human Body", by Gwilym G. Davis. Also available from Amazon: Applied anatomy: The construction of the human body.
The seminal vesicles are about 5 cm. (2 in.) long and lie on the bladder above the prostate. They diverge on each side toward the ureters, which they overlap and which intervene between the vesicles and bladder wall. The vasa deferentia run along the inner border of the vesicles and join the ducts from the vesicles to form the common ejaculatory ducts just before entering the posterior portion of the prostate. Their upper portion is covered by the peritoneum of the rectovesical pouch. They are fastened to the bladder by the rectovesical fascia, and are in close relation with the prostatic plexus and vesical veins. They are within reach of the finger introduced through the anus and may be massaged and their contents expressed. They have been excised for tuberculous disease. When normal they are not readily recognized by touch, but in disease are easily felt. Operations on them are conducted like those of perineal prostatectomy, but, as they lie higher, beyond the prostate, it is almost impossible to bring them well into view for operative purposes. The seminal vesicles are nothing more than blind diverticula from the vasa deferentia and partake of its diseases. The epididymis, vas deferens, seminal vesicles, and prostate are all frequently involved in tuberculosis of the genito-urinary tract (Fig. 456).