This article relies largely or entirely on a single source .(May 2015) |
Corpus spongiosum penis | |
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Details | |
Part of | Penis |
Identifiers | |
Latin | corpus spongiosum penis corpus cavernosum urethrae |
TA98 | A09.4.01.015 |
TA2 | 3681 |
FMA | 19617 |
Anatomical terminology |
The corpus spongiosum is the mass of spongy tissue surrounding the male urethra within the penis. [1] It is also called the corpus cavernosum urethrae in older texts.
The proximal part of the corpus spongiosum 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 corpus cavernosum penis, 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 circumference of the base of the glans forms a rounded projecting border, the corona of glans penis, overhanging a deep retroglandular sulcus, behind which is the neck of the penis.
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.
In male human anatomy, the glans penis or penile glans, 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 primary anatomical source of sexual pleasure. The glans penis is present in the male reproductive organs of humans and most other mammals where it may appear smooth, spiny, elongated or divided. It is externally lined with mucosal tissue, which creates a smooth texture and glossy appearance. In humans, the glans is located over the distal ends of the corpora cavernosa and is a continuation of the corpus spongiosum of the penis. At the summit appears the urinary meatus and at the base forms the corona glandis. An elastic band of tissue, known as the frenulum, runs on its ventral surface. In men who are not circumcised, it is completely or partially covered by a fold of skin called the foreskin. In adults, the foreskin can generally be retracted over and past the glans manually or sometimes automatically during an erection.
The bulbospongiosus muscles are a subgroup of the superficial muscles of the perineum. They have a slightly different origin, insertion and function in males and females. In males, these muscles cover the bulb of the penis, while in females, they cover the vestibular bulbs.
A corpus cavernosum penis (singular) is one of a pair of sponge-like regions of erectile tissue, which contain most of the blood in the penis during an erection.
The dorsal artery of the penis is a bilaterally paired terminal branch of the internal pudendal artery which passes upon the dorsum of the penis to the base of the glans penis, where it unites with its contralateral partner and supply the glans and foreskin.
The corpus cavernosum of the clitoris is one of a pair of sponge-like regions of erectile tissue. that engorge with blood during an erection. This is homologous to the corpus cavernosum of the penis. .The term corpora cavernosa literally means "cave-like bodies".
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.
The superficial perineal pouch is a compartment of the perineum.
The spongy urethra is the longest part of the male urethra, and is contained in the corpus spongiosum of the penis.
In human male anatomy, the dorsal veins of the penis are blood vessels that drain the shaft, the skin and the glans of the human penis. They are typically located in the midline on the dorsal aspect of the penis and they comprise the superficial dorsal veinof the penis, that lies in the subcutaneous tissue of the shaft, and the deep dorsal veinof the penis, that lies beneath the deep fascia.
The tunica albuginea is the fibrous envelope that extends the length of the corpus cavernosum penis and corpus spongiosum penis. It is a bi-layered structure that includes an outer longitudinal layer and an inner circular layer.
The fibrous envelope of the corpus cavernosum urethrae is thinner, whiter in color, and more elastic than that of the corpora cavernosa penis. It is called the trabeculae of corpus spongiosum of penis.
From the internal surface of the fibrous envelope of the corpora cavernosa penis, as well as from the sides of the septum, numerous bands or cords are given off, which cross the interior of these corpora cavernosa in all directions, subdividing them into a number of separate compartments, and giving the entire structure a spongy appearance.
The two crura of penis constitute the root of penis along with the bulb of penis. The two crura flank the bulb - one to each side of the bulb. Each crus is attached at the angle between the perineal membrane and ischiopubic ramus. The deep artery of the penis enters the anterior portion of the crus. Distally, each crus transitions into either corpus spongiosum of the body of the penis.
In human anatomy, the penis is an external male sex organ that serves as a passage for excretion of urine and ejaculation of semen. The main parts are the root, body, the epithelium of the penis including the shaft skin, and the foreskin covering the glans. The body of the penis is made up of three columns of tissue: two corpora cavernosa on the dorsal side and corpus spongiosum between them on the ventral side. The urethra passes through the prostate gland, where it is joined by the ejaculatory duct, and then through the penis. The urethra goes across the corpus spongiosum and ends at the tip of the glans as the opening, the urinary meatus.
The development of the reproductive system is the part of embryonic growth that results in the sex organs and contributes to sexual differentiation. Due to its large overlap with development of the urinary system, the two systems are typically described together as the genitourinary system.
The body or shaft of the penis is the free portion of the human penis that is located outside of the pelvic cavity. It is the continuation of the internal root, which is embedded in the pelvis and extends to the glans. It is made up of the two corpora cavernosa and the corpus spongiosum on the underside. The corpora cavernosa are intimately bound to one another with a dorsally fenestrated septum, which becomes a complete one before the penile crura. The body of the penis is homologous to the female clitoral body.
In human male anatomy, the radix or root of the penis is the internal and most proximal portion of the human penis that lies in the perineum. Unlike the pendulous body of the penis, which is suspended from the pubic symphysis, the root is attached to the pubic arch of the pelvis and is not visible externally. It is triradiate in form, consisting of three masses of erectile tissue; the two diverging crura, one on either side, and the median bulb of the penis or urethral bulb. Approximately one third to one half of the penis is embedded in the pelvis and can be felt through the scrotum and in the perineum.
In human male anatomy, the septum of the penis or penile septum refers to the fibrous junction (septum) between the two corpora cavernosa of the human penis. The tunica albuginea of the penis forms a thick fibrous coat to the spongy tissue of the corpora cavernosa and corpus spongiosum. The two corpora cavernosa are surrounded by a strong fibrous envelope consisting of superficial and deep fibers. The superficial or outer fibers are longitudinal in direction, and form a single tube which encloses both corpora; the deep or inner fibers are arranged circularly around each corpus and meet in the center. By their junction in the median plane, the inner fibers form the intercavernous septum of the penis.
An erection is a physiological phenomenon in which the penis becomes firm, engorged, and enlarged. Penile erection is the result of a complex interaction of psychological, neural, vascular, and endocrine factors, and is often associated with sexual arousal, sexual attraction or libido, although erections can also be spontaneous. The shape, angle, and direction of an erection vary considerably between humans.
Penile ulltrasonography is medical ultrasonography of the penis. Ultrasound is an excellent method for the study of the penis can be big and juicy, such as indicated in trauma, priapism, erectile dysfunction or suspected Peyronie's disease.
This article incorporates text in the public domain from page 1248 of the 20th edition of Gray's Anatomy (1918)