The corpus spongiosum is the mass of spongy tissue surrounding the male

urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra con ...

within the

penis A penis (plural ''penises'' or ''penes'' () is the primary sexual organ that male animals use to inseminate females (or hermaphrodites) during copulation. Such organs occur in many animals, both vertebrate and invertebrate, but males do n ...

. It is also called the corpus cavernosum urethrae in older texts.

Anatomy

The proximal part of the corpus spongiosum is expanded to form the

urethral bulb Just before each crus of the penis meets its fellow, it presents a slight enlargement, which Georg Ludwig Kobelt named the bulb of the corpus cavernosum penis. The bulb of penis is also known as the urethral bulb. The bulb is homologous to the v ...

, and lies in apposition with the

inferior fascia of the urogenital diaphragm The perineal membrane is an anatomical term for a fibrous membrane in the perineum. The term "inferior fascia of urogenital diaphragm", used in older texts, is considered equivalent to the perineal membrane. It is the superior border of the su ...

, 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 In male human anatomy, the glans penis, commonly referred to as the glans, is the bulbous structure at the distal end of the human penis that is the human male's most sensitive erogenous zone and their primary anatomical source of sexual p ...

, is moulded on the rounded ends of the

corpus cavernosum penis A corpus cavernosum penis (singular) (literally "cave-like body" of the penis, plural corpora cavernosa) is one of a pair of sponge-like regions of erectile tissue, which contain most of the blood in the penis during an erection. Such a corpus ...

, extending farther on their upper than on their lower surfaces. At the summit of the glans is the slit-like vertical opening known as the external urethral orifice, or the

urinary meatus The urinary meatus, (, ) also known as the external urethral orifice, is the opening of the urethra. It is the point where urine exits the urethra in both sexes and where semen exits the urethra in males. The meatus has varying degrees of sensiti ...

. The circumference of the base of the glans forms a rounded projecting border, the

corona of glans penis The corona of glans penis or penis crown refers to the rounded projecting border that forms at the base of the glans in human males. The corona overhangs a mucosal surface, known as the neck of the penis, which separates the shaft and the glans. ...

, overhanging a deep retroglandular 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

File:Illu penis.jpg, Structure of the penis File:Gray588.png, The penis in transverse section, showing the blood vessels. File:Gray1158.png, Diagram of the arteries of the

. File:Gray1156.png, Vertical section of bladder, penis, and urethra. File:Penis_cross_section.svg, Cross section of penis File:Gray1155.png, Transverse section of the penis. File:Gray1154.png, The constituent cavernous cylinders of the penis. File:Normal penis ultrasound.jpg,

Medical ultrasonography Medical ultrasound includes diagnostic techniques (mainly medical imaging, imaging techniques) using ultrasound, as well as therapeutic ultrasound, therapeutic applications of ultrasound. In diagnosis, it is used to create an image of internal ...

of a normal penis.

References

External links

* - "The Male Pelvis: The Urethra" {{Authority control Mammal male reproductive system Human penis anatomy fr:Corps spongieux pl:Ciało gąbczaste pt:Corpo esponjoso

Anatomy

Function

Additional images

See also

References

External links