Introduction:
Knowledge of the prostatic portion of the urethra is essential to the comprehension of urinary continence phenomena. However, there are only a small number of studies that have addressed this relationship and analyzed the ultrastructure of the prostatic urethra.

Material and methods:
A three-dimensional analysis of the fibrous components and the extracellular matrix of the prostatic urethra in 10 normal humans was performed with a scanning electron microscope. The prostates were obtained from 10 men (18 to 30 years old) who had died from accidents. The specimens were fixated in a modified Karnovsky solution for 48 h at 4°C, washed in a sodium phosphate buffered solution (PBS) for 2 h at 4°C and then incubated in 40 ml of 2 M NaOH at room temperature for 8 days (cellular digestion). Afterwards, the three-dimensional organization of the prostatic urethra stroma was observed.

Results:
It was observed that the prostates had a narrowed fibrous septa which condensed and formed a network in order to support the submucosa. Furthermore, it was also observed that they formed a homogeneous fibrous layer (pars fibroreticularis), which lined the urethral wall.

Conclusions:
Knowledge of the urethra composition is essential to understand the physiopathological aspects of urinary incontinence. Moreover, our results showed a great amount of connective tissue underlying the prostatic urethra wall.