Objective      To obtain important clinical data for the transurethral endoscopic operation to the seminal tract by accurately measuring the physiological data on the distal regions of adult male genital tract.       Methods      All the intact postoperative histological specimens from 35 cases of prostate cancer (Pca) treated by laparoscopic radical prostatectomy (LRP) and 11 cases of bladder cancer (Bca) treated by laparoscopic radical cystectomy (LRC) were collected for accurate observation and precise measurement for its fine structure. A comparative analysis was performed to the results of their preoperative pelvic magnetic resonance imaging (MRI) with the anatomic data from postoperative histological specimens. The morphological characteristics of prostatic utricle

and the relationship with the bilateral ejaculatory duct orifice were observed by transurethral endoscopy on 109 patients with benign prostatic hyperplasia who were treated by transurethral resection of prostate.        Results      The anatomic data on the postoperative specimens showed that the lengths of seminal vesicles (SVs) were 39.7±7.4 mm for the left

and 41.4±8.6 mm for the right side

the widths were 16.5±3.3 mm for the left and 16.4±3.0 mm for the right side

and the thickness were 7.8±2.4 mm for the left and 7.8±2.3 mm for the right side. The lengths of ejaculation ducts were 15.0±2.5 mm for the left and 14.9±2.4 mm for right side

the diameters were 1.2±0.2 mm for the left and 1.1±0.2 mm for the right side. The prostatic utricle was observed in 47.8% (22/46) cases with the depth of (6.7±1.7) mm. Measurement of SV on MR images showed that their lengths were 39.4±6.6 and 41.3±7.6 mm respectively for the left and right sides

and their widths were 17.1±3.4 and 16.4±2.9 mm respectively. The data of SVs sizes were highly consistent between the results from preoperative MR images and postoperative specimens. Endoscopic observation showed that 78.9% (86/109) cases had obvious prostate utricle openings located at the top of the verumontanum

and the other cases (21.1%

23/109) had no obvious openings. The ejaculatory duct orifices were commonly located at bilateral sides in about 2 mm away from the prostatic utricle openings

and they formed a triangular or linear arrangement.       Conclusion      Our obtained data on the anatomical structure of male distal genital tract are of important guiding significance for endoscopic techniques in clinical practice. MR imaging shows better distinguishing value for this region.