Corpus spongiosum
Corpus spongiosum penis
Also known as: bulb of penis, glans penis
The single ventral erectile body of the penis that surrounds the spongy urethra, expanding proximally into the bulb and distally into the glans; its thin tunica keeps the urethra open during erection.
Overview
The corpus spongiosum begins as the bulb of the penis, attached to the inferior surface of the perineal membrane and covered by bulbospongiosus, where the urethra enters it from above. It runs along the ventral groove between the corpora cavernosa and expands distally to form the glans penis, which caps the ends of the corpora cavernosa.
Its tunica albuginea is thin and elastic, so during erection it becomes engorged but remains compressible, allowing semen to pass along the spongy urethra. Rhythmic contraction of bulbospongiosus at ejaculation (and after micturition) expels the urethral contents.
- Location
Ventral part of the penis, from the bulb in the superficial perineal pouch to the glans.
Anatomy
- Innervation
Cavernous nerves; glans sensory via the dorsal nerve of the penis.
- Arterial supply
Arteries of the bulb of the penis and dorsal arteries (internal pudendal).
- Development
Urethral folds and genital tubercle; homologue of the bulbs of the vestibule (and glans clitoridis).
Function
- Contains and protects the spongy urethra.
- Forms the glans (sensory, erectile).
Clinical significance
Straddle injury
A fall astride an object crushes the bulbar urethra against the pubic arch; urine extravasates into the superficial perineal pouch (scrotum, penis, anterior abdominal wall). Blood at the meatus contraindicates blind catheterisation.
Compiled from standard anatomy and physiology references — see the Reproductive System sources. For education only; not medical advice.