Corpus spongiosum penis

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Corpus spongiosum penis
Transverse section of the penis.
The constituent cavernous cylinders of the penis.
Gray's	subject #262 1248
Dorlands/Elsevier	c_56/12260814

Corpus spongiosum (Plural: Corpora Spongiosa) (also known as corpus cavernosum urethrae in older texts) is the mass of spongy tissue surrounding the male urethra within the penis.

Contents 1 Anatomy 2 Function 3 See also 4 Additional images 5 External links

[edit] Anatomy

Behind, it is expanded to form the urethral bulb, and lies in apposition with the inferior fascia of the urogenital diaphragm, from which it receives a fibrous investment.

The urethra enters the bulb nearer to the upper than to the lower surface. On the latter there is a median sulcus (groove), from which a thin fibrous septum (wall) projects into the substance of the bulb and divides it imperfectly into two lateral lobes or hemispheres.

The portion of the corpus spongiosum in front of the bulb lies in a groove on the under surface of the conjoined corpora cavernosa penis. It is cylindrical in form and tapers slightly from behind forward. Its anterior end is expanded in the form of an obtuse cone, flattened from above downward. This expansion, termed the glans penis, is moulded on the rounded ends of the corpora cavernosa penis, extending farther on their upper than on their lower surfaces.

At the summit of the glans is the slit-like vertical external urethral orifice, also known as the meatus.

The circumference of the base of the glans forms a rounded projecting border, the corona glandis, overhanging a deep retroglandular sulcus, behind which is the neck of the penis.

[edit] Function

The function of the corpus spongiosum in erection is to prevent the urethra from pinching closed, thereby maintaining the urethra as a viable channel for ejaculation. To do this, the corpus spongiosum remains pliable during erection while the corpora cavernosum penis becomes engorged with blood.

[edit] See also

• Corpus cavernosum penis
• Spongy urethra

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

[edit] Additional images

Structure of the penis

The penis in transverse section, showing the bloodvessels.

Diagram of the arteries of the penis.

Vertical section of bladder, penis, and urethra.

[edit] External links

• SUNY Labs 44:06-0204 - "The Male Pelvis: The Urethra"
• corpus+spongiosum+penis at eMedicine Dictionary
• corpus+spongiosum+urethrae+muliebris at eMedicine Dictionary

v • d • e Male reproductive system Scrotum layers (skin, Dartos, External spermatic fascia, Cremaster/Cremasteric fascia, Internal spermatic fascia) • Perineal raphe • Spermatic cord Testes layers (Tunica vaginalis, Tunica albuginea, Tunica vasculosa testis) • Appendix • Mediastinum • Lobules • Septa • Leydig cell • Sertoli cell • Blood-testis barrier Spermatogenesis Spermatogonium • Spermatocytogenesis • Spermatocyte • Spermatidogenesis • Spermatid • Spermiogenesis • Spermatozoon seminal tract Seminiferous tubules (Tubuli seminiferi recti, Rete testis, Efferent ducts) • Epididymis  (Appendix, Stereocilia) • Vas deferens (Ampulla) • Ejaculatory duct urinary tract Internal urethral orifice • Urethra (Prostatic, Intermediate, Spongy, Navicular fossa) • External urethral orifice accessory glands Seminal vesicles  (Excretory duct of seminal gland) • Prostate  (Urethral crest/Seminal colliculus/Prostatic utricle/Ejaculatory duct, Prostatic sinus/Prostatic ducts) • Bulbourethral glands Penis root (Crus, Bulb, Fundiform ligament, Suspensory ligament) • body (Corpus cavernosum, Corpus spongiosum) • glans (Foreskin, Frenulum, Corona) • fascia (superficial/subcutaneous, deep/Buck's) • Tunica albuginea - Septum of the penis