Navicular fossa of male urethra

The cavernous portion of the urethra is narrow, and of uniform size in the body of the penis, measuring about 6 mm. in diameter; it is dilated behind, within the bulb, and again anteriorly within the glans penis, where it forms the fossa navicularis urethræ.

The navicular fossa is the spongy part of the male urethra located at the Glans Penis portion. It is essentially the part right before the External Urethral Orifice. It is lined by stratified squamous, non-keratinizing epithelium if viewed histologically. DOTE Anatomy - 2007