Organ
Bulb of the penis
Expanded proximal spongiosum beneath the perineal membrane
High-yield
The bulb belongs to the corpus spongiosum. Its urethral entry is superior to the rounded posterior end, and the covering muscle is bulbospongiosus.
Overview
The bulb is the posterior enlargement of the corpus spongiosum at the root of the penis. It attaches to the perineal membrane between the two crura and is covered by bulbospongiosus. The urethra enters its superior aspect before continuing through the spongiosum.
Reference facts
- Location
- At the penile root in the superficial perineal pouch, attached to the inferior perineal membrane between the crura.
- Parts
- An enlarged segment of corpus spongiosum containing the proximal spongy urethra, which receives the bulbourethral ducts.
- Blood supply
- Supplied chiefly by the artery to the bulb from the internal pudendal circulation.
- Innervation
- Erectile tissue receives autonomic cavernous fibers and pudendal sensory fibers; the overlying skeletal muscle receives perineal motor branches.
- Venous/Lymphatic drainage
- Venous return reaches internal pudendal and pelvic plexuses; lymphatic connections involve deep inguinal and pelvic pathways, differing by penile and urethral region.
- Relations
- Bulbospongiosus covers it inferiorly; the perineal membrane and sphincter region lie superiorly, with a crus on either side.
- Function
- Anchors the proximal spongiosum. Compression by bulbospongiosus assists expulsion through the urethra and contributes to erection.
Clinical correlation
A straddle injury can damage the bulbar urethra. The spread of blood or urine depends on which fascial layers are disrupted; communication with the superficial perineal and lower abdominal spaces occurs when containment by the deeper fascia is lost.
Frequently asked questions
Where is the bulb of the penis located?
At the penile root in the superficial perineal pouch, attached to the inferior perineal membrane between the crura.
What does the bulb of the penis do?
Anchors the proximal spongiosum. Compression by bulbospongiosus assists expulsion through the urethra and contributes to erection.
What are the parts of the bulb of the penis?
An enlarged segment of corpus spongiosum containing the proximal spongy urethra, which receives the bulbourethral ducts.
What is the blood supply of the bulb of the penis?
The bulb of the penis is supplied by the supplied chiefly by the artery to the bulb from the internal pudendal circulation.