Bulb of penis

The bulb of penis is the proximal/posterior bulged end of the (unpaired median) corpus spongiosum penis. Together with the two crura (one crus on each side of the bulb), it constitutes the root of the penis.  It is covered by the bulbospongiosus.

Proximally/posteriorly, the bulb of penis extends towards the perineal body. The bulb exhibits a slight yet palpable midline notch upon its inferior aspect. 

The male urethra enters the penis at the superior aspect of the anterior part of the bulb (most of the bulb is thus situated inferoposteriorly to the urethra), and the arteries of bulb of penis enter near the urethra. 

The bulb of penis is homologous to the vestibular bulbs in females.