Navicular fossa of urethra

The navicular fossa of the urethra (Fossa of Morgagni) is an anatomical structure located in the glans penis. It represents the distal widening of the male urethra just before the external urethral meatus. This segment of the urethra is characterized by a wider caliber compared to the proximal urethra, forming a vertical elliptical shape that resembles a laterally compressed slit-like passage.[1]

The dorsal part of the navicular fossa of the urethra presents the lacuna magna (Guérin's sinus) that is a congenital large recess, horizontal to the urethra, located on the dorsal part of the navicular fossa, separated from the navicular fossa by the valve of navicular fossa (Guérin’s valve) is as a leaflet between the lacuna magna and the navicular fossa of male urethra.

The fossa navicularis is covered by a thin layer of fibrous tissue known as the septum glandis, which is an extension of the tunica albuginea of the corpus cavernosum and the corpus spongiosum. This anatomical configuration plays a role in the flow dynamics of urine, potentially acting as a "flow-control chamber" by increasing pressure and decreasing the velocity of urine flow as it exits the urethra.[1]

The anatomy of fossa navicularis is involved for surgical procedures involving the glanular urethra, such as hypospadias repair and the management of urethral strictures.[2-3]