The artery of the urethral bulb (artery of bulb of penis, bulbourethral artery) is a short vessel of large caliber which arises from the internal pudendal

Internal pudendal artery

The internal pudendal artery is an artery that branches off the internal iliac artery, providing blood to the external genitalia.The internal pudendal artery is the terminal branch of the anterior trunk of the internal iliac artery...

 between the two layers of fascia of the urogenital diaphragm

Urogenital diaphragm

Older texts have asserted the existence of an urogenital diaphragm, also called the triangular ligament, which was described as a layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of the urogenital diaphragm and superior fascia of the...

; it passes medialward, pierces the inferior fascia of the urogenital diaphragm, and gives off branches which ramify in the bulb of the urethra and in the posterior part of the corpus spongiosum

Corpus spongiosum

Corpus spongiosum is the mass of spongy tissue surrounding the male urethra within the penis...

.

It gives off a small branch to the bulbo-urethral gland.