The vestibular bulbs, also known as the clitoral bulbs, are aggregations of erectile tissue that are an internal part of the clitoris

Clitoris

The clitoris is a sexual organ that is present only in female mammals. In humans, the visible button-like portion is located near the anterior junction of the labia minora, above the opening of the urethra and vagina. Unlike the penis, which is homologous to the clitoris, the clitoris does not...

. They can also be found throughout the vestibule: next to the clitoral body

Clitoral body

The clitoral body corpus clitoridis is an internal portion of the clitoris. It is attached to the clitoral glans, which is external. After several inches into the body, it then splits into the clitoral crura, which are also internal and are "V" shaped....

, clitoral crura

Clitoral crura

- Anatomy :The clitoral crura are an internal portion of the clitoris. A single one is called a clitoral crus. They are shaped like an inverted "V" with the vertex of the "V" connecting to the clitoral body....

, urethra

Urethra

In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...

, urethral sponge

Urethral sponge

The urethral sponge is a spongy cushion of tissue, found in the lower genital area of women, that sits against both the pubic bone and vaginal wall, and surrounds the urethra.-Functions:...

, and vagina

Vagina

The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...

.

They are to the left and right of the urethra, urethral sponge, and vagina.

The vestibular bulbs are homologous to the bulb of penis

Bulb of penis

Just before each crus of the penis meets its fellow it presents a slight enlargement, named by Kobelt the bulb of the corpus spongiosum penis.It is homologous to the vestibular bulbs in females....

 and adjoining part of the corpus spongiosum

Corpus spongiosum

Corpus spongiosum is the mass of spongy tissue surrounding the male urethra within the penis...

 of the male, and consists of two elongated masses of erectile tissue, placed one on either side of the vaginal orifice

Vaginal orifice

The vaginal orifice is a median slit below and behind the opening of the urethra; its size varies inversely with that of the hymen.-External links: - "The Female Perineum: The Vulva"...

 and united to each other in front by a narrow median band termed the pars intermedia.

Their posterior ends are expanded and are in contact with the greater vestibular glands; their anterior ends are tapered and joined to one another by the pars intermedia; their deep surfaces are in contact with the inferior fascia of the urogenital diaphragm

Urogenital diaphragm

Older texts have asserted the existence of an 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 the urogenital diaphragm and superior fascia of the...

; superficially they are covered by the bulbospongiosus.

Physiology

During sexual response

Sexual arousal

Sexual arousal, or sexual excitement, is the arousal of sexual desire, during or in anticipation of sexual activity. Things that precipitate human sexual arousal are called erotic stimuli, or colloquially known as turn-ons. There are many potential stimuli, both physical or mental, which can cause...

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

Erection

Penile erection is a physiological phenomenon where the penis becomes enlarged and firm. Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is usually, though not exclusively, associated with sexual arousal...

. As the clitoral bulbs fill with blood, they tightly cuff the vaginal opening, causing the vulva to expand outward. The blood inside the bulb’s erectile tissue

Erectile tissue

Erectile tissue is tissue in the body that can become erect, usually by becoming engorged with blood.-Erectile tissue in the clitoris and penis:...

 is released to the circulatory system by the spasms of orgasm

Orgasm

Orgasm is the peak of the plateau phase of the sexual response cycle, characterized by an intense sensation of pleasure...

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

External links

- "The Female Perineum: Muscles of the Superficial Perineal Pouch"