Click image to view full screen

Posterior to the base, identify the ampulla of ductus deferens and more lateral to them, the seminal vesicles [these structures are visible in this specimen because the line of section is slightly lateral to the median plane of the pelvis]. On the internal surface of the bladder identify the trigone. The trigone is a smooth triangular area which is bounded superolaterally by the openings of the ureters and inferiorly by the internal urethral orifice. The remainder of the internal surface of the bladder has thick mucosal folds.

Links and References:
Grant's: 3.23,3.24,3.27
Netter (1ed.): 342 (2ed.): 338
Rohen/Yokochi: 317