In female anatomy, the vestibular bulbs, bulbs of the vestibule or clitoral bulbs are two elongated masses of

erectile tissue Erectile tissue is tissue in the body with numerous vascular spaces, or cavernous tissue, that may become engorged with blood. However, tissue that is devoid of or otherwise lacking erectile tissue (such as the labia minora, vestibule, vagina and ...

typically described as being situated on either side of the vaginal opening. They are united to each other in front by a narrow median band. Some research indicates that they do not surround the vaginal opening, and are more closely related to the

clitoris In amniotes, the clitoris ( or ; : clitorises or clitorides) is a female sex organ. In humans, it is the vulva's most erogenous zone, erogenous area and generally the primary anatomical source of female Human sexuality, sexual pleasure. Th ...

than to the vestibule. They constitute the root of the clitoris along with the crura.

Structure

Research indicates that the vestibular bulbs are more closely related to the

than to the vestibule because of the similarity of the

trabecula A trabecula (: trabeculae, from Latin for 'small beam') is a small, often microscopic, biological tissue, tissue element in the form of a small Beam (structure), beam, strut or rod that supports or anchors a framework of parts within a body or ...

r and erectile tissue within the clitoris and bulbs, and the absence of trabecular tissue in other genital organs, with the erectile tissue's trabecular nature allowing engorgement and expansion during

sexual arousal Sexual arousal (also known as sexual excitement) describes the Physiology, physiological and psychological responses in preparation for sexual intercourse or when exposed to Sexual stimulation, sexual stimuli. A number of physiological response ...

. Ginger et al. state that although a number of texts report that they surround the vaginal opening, this does not appear to be the case and tunica albuginea does not envelop the erectile tissue of the bulb. The vestibular bulbs are homologous to the

bulb of penis The bulb of penis is the proximal/posterior bulged end of the (unpaired median) corpus spongiosum penis. Together with the two crura (one crus on each side of the bulb), it constitutes the root of the penis. It is covered by the bulbospongiosu ...

of the male and consist of two elongated masses of erectile tissue. Their posterior ends are expanded and are in contact with the greater vestibular glands; their anterior ends form the ''infra-corporeal residual spongy part'' (RSP), which are tapered and joined to one another (the commissure of the bulbs) by the pars intermedia; their deep surfaces are in contact with the inferior fascia of the

urogenital diaphragm Older texts have asserted the existence of a urogenital diaphragm, also called the triangular ligament, which was described as a layer of the pelvis that separates the deep perineal sac from the upper pelvis, lying between the inferior fascia of ...

; superficially, they are covered by the

bulbospongiosus The bulbospongiosus muscles (in older texts bulbocavernosus and, for female muscle, constrictor cunni) are a subgroup of the superficial muscles of the perineum. They have a slightly different origin, insertion and function in males and females. ...

. The residual spongy part is a strand of erectile tissue that runs ventrally across the external clitoral body and ends as the glans clitoridis.

Physiology

During the response to

, the bulbs fill with blood, which then becomes trapped, causing

erection An erection (clinically: penile erection or penile tumescence) is a Physiology, physiological phenomenon in which the penis becomes firm, engorged, and enlarged. Penile erection is the result of a complex interaction of psychological, neural, ...

. As the clitoral bulbs fill with blood, they tightly cuff the vaginal opening, causing the

vulva In mammals, the vulva (: vulvas or vulvae) comprises mostly external, visible structures of the female sex organ, genitalia leading into the interior of the female reproductive tract. For humans, it includes the mons pubis, labia majora, lab ...

to expand outward. This puts pressure on nearby structures that include the corpora cavernosa and crura, inducing pleasure. The blood inside the bulb's erectile tissue is released to the circulatory system by the spasms of

orgasm Orgasm (from Greek , ; "excitement, swelling"), sexual climax, or simply climax, is the sudden release of accumulated sexual excitement during the sexual response cycle, characterized by intense sexual pleasure resulting in rhythmic, involu ...

, but if orgasm does not occur, the blood will exit the bulbs over several hours.

Additional images

File:EdSim Clitoris anatomy.jpg, The sub-areas of the clitoris—areas include clitoral glans, body, crura. The vestibular bulbs and corpora cavernosa are also shown. File:Vulva and Clitoris 1.png, Clitoral bulbs under the labia and on both sides of the vaginal entrance File:Clitoris Penis Homology 1.png, Homology of the male and female bulbs

References

External links

* - "The Female Perineum: Muscles of the Superficial Perineal Pouch" * {{DEFAULTSORT:Vestibular Bulbs Clitoris Mammal female reproductive system