Corpus spongiosum penis

Corpus spongiosum penis
Lower Parts of the Genital and Urinary Tracts in the Male
Dissection of the Penis
Details
Identifiers
Latin	Corpus spongiosum penis (plural: Corpora spongiosa penium), (corpus cavernosum urethrae)
Dorlands /Elsevier	c_56/12260814
TA	A09.4.01.015
FMA	19617
*Anatomical terminology* [edit on Wikidata]

The corpus spongiosum is the mass of spongy tissue surrounding the male urethra within the penis. Although called corpus cavernosum in older texts, this is not correct.

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 superior than to the inferior 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 (Meiring's sulcus), behind which is the neck of the penis.

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 cavernosa penis become engorged with blood.

Additional images

Structure of the penis
The penis in transverse section, showing the blood vessels.
Diagram of the arteries of the penis.
Vertical section of bladder, penis, and urethra.
Cross section of penis
Transverse section of the penis.
The constituent cavernous cylinders of the penis.

References

This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918)

External links

Anatomy photo:44:06-0204 at the SUNY Downstate Medical Center - "The Male Pelvis: The Urethra"

Male reproductive system

Internal

Seminal tract

Testes	layers Tunica vaginalis Tunica albuginea Tunica vasculosa Appendix Mediastinum Lobules Septa Leydig cell Sertoli cell Blood–testis barrier

Spermatogenesis	Spermatogonium Spermatocytogenesis Spermatocyte Spermatidogenesis Spermatid Spermiogenesis Spermatozoon

Other	Seminiferous tubules Tubuli seminiferi recti Rete testis Efferent ducts Epididymis Appendix Stereocilia Paradidymis Spermatic cord Vas deferens Ampulla Ejaculatory duct

Accessory glands

External

Penis	root Crus Bulb Fundiform ligament Suspensory ligament body Corpus cavernosum Corpus spongiosum glans Foreskin Frenulum Corona fascia superficial deep Tunica albuginea Septum of the penis

Urinary tract	Internal urethral orifice Urethra Prostatic Intermediate Spongy Navicular fossa External urethral orifice Lacunae of Morgagni Urethral gland

Scrotum	layers skin Dartos External spermatic fascia Cremaster Cremasteric fascia Internal spermatic fascia Perineal raphe Scrotal septum

This article is issued from Wikipedia - version of the Monday, October 26, 2015. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.