Dominic Stone
The bulbocavernosus muscle, also known as the bulbospongiosus muscle, is a muscle of the perineum, the area between the anus and the genitals. In males, it surrounds the bulb of the penis and facilitates urination, ejaculation, and erection. In females, it is divided into two halves that extend from behind the clitoris to the central tendon of the perineum and serves to constrict the vagina and facilitate clitoral erection. The bulbocavernosus muscle is innervated by the perineal nerve, a branch of the pudendal nerve, and plays a crucial role in sexual function and urinary control in both sexes.
| Characteristics | Values |
|---|---|
| Muscle type | Superficial muscle of the perineum |
| Male location | Base of the penis |
| Female location | Divided into halves that extend from just behind the clitoris to the central tendon of the perineum |
| Male function | Controls erection, ejaculation, and urination |
| Female function | Contributes to clitoral erection, the contractions of orgasm, and closes the vagina |
| Innervation | Perineal nerve (branch of the pudendal nerve) |
| Blood supply | Internal pudendal artery |
| Reflex | Bulbocavernosus reflex |
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What You'll Learn
The bulbocavernosus muscle is a perineal muscle
The bulbocavernosus muscle, also known as the bulbospongiosus muscle, is a perineal muscle. In males, it surrounds the bulb of the penis and is involved in urination, ejaculation, and erection. In females, it is divided into two halves that extend from behind the clitoris to the central tendon of the perineum and serves to constrict the vagina and facilitate clitoral erection.
The bulbocavernosus muscle is a sexually dimorphic muscle, meaning it has different functions and structures in males and females. In males, it is composed of two symmetrical parts that are united along the median line by a tendinous perineal raphe. It originates from the central tendinous point of the perineum and helps to facilitate urination by emptying the penile urethra. Additionally, it contributes to ejaculation by acting as a pump that forcefully propels sperm out of the body during the expulsion phase. The muscle also plays a role in erection by compressing the erectile tissue of the bulb and the deep dorsal vein of the penis.
In females, the bulbocavernosus muscle is found on each side of the vaginal orifice, covering the bulbs of the vestibule. It is not united by a tendinous perineal raphe, and the two halves arise from the same central tendinous point of the perineum. The muscle contributes to clitoral erection and facilitates the emptying of the greater vestibular glands. Additionally, it supports the perineal body in both sexes.
The bulbocavernosus muscle is innervated by the deep or muscular branch of the perineal nerve, which is a branch of the pudendal nerve. The blood supply to this muscle comes from the internal pudendal artery, via its branch, the perineal artery. The bulbocavernosus reflex is a response to sudden manual compression of the glans penis or clitoris, causing reflex contraction of the muscle and the external anal sphincter. This reflex can be detected by palpating the skin behind the scrotum or placing a finger in the anal canal.
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Its function differs in males and females
The bulbocavernosus muscle is a muscle of the perineum, the area between the anus and the genitals. Its function does differ in males and females.
In males, the bulbocavernosus muscle surrounds the bulb of the penis and is directly related to erectile dysfunction. It can be contracted to expel the last drops of urine or semen. It also contributes to erection, the contractions of orgasm, and ejaculation.
In females, the bulbocavernosus muscle is divided into halves that extend from just behind the clitoris to the central tendon of the perineum. It serves to constrict the vagina and contributes to clitoral erection and the contractions of orgasm. It covers the vestibular bulbs, which are two erectile organs situated in the anterior region of the perineum.
The difference in function between males and females is due to the difference in their origin, insertion, and innervation. In males, the bulbocavernosus muscle covers the bulb of the penis, while in females, it covers the vestibular bulbs. In both sexes, the muscle is innervated by the deep or muscular branch of the perineal nerve, a branch of the pudendal nerve. However, men have more neurons in Onuf's nucleus than women, which is a cell group in the sacral spinal cord that innervates the bulbocavernosus muscle.
The presence and function of the bulbocavernosus muscle also differ between species. For example, in rats, the muscle is present in males but degenerates in females around the time of birth. However, in other species such as dogs, hyenas, and monkeys, the muscle is retained in females, although they have fewer motoneurons in Onuf's nucleus than males.
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It is innervated by the perineal nerve
The bulbocavernosus muscle is a muscle of the perineum, the area between the anus and the genitals. In males, it surrounds the bulb of the penis and can be contracted to expel the last drops of urine or semen. In females, it is divided into halves that extend from just behind the clitoris to the central tendon of the perineum and serves to constrict the vagina. The bulbocavernosus muscle is innervated by the perineal nerve, specifically the deep or muscular branch of the perineal nerve, which is a branch of the pudendal nerve. This nerve is responsible for mediating the bulbocavernosus reflex, which is a contraction of the bulbocavernosus muscle in response to stimulation of the glans penis or clitoris. The reflex is important for testing the conus medullaris and the S2-S4 pelvic nerves, which are located at the distal end of the spinal cord.
The bulbocavernosus muscle has a slightly different origin, insertion, and function in males and females. In males, the muscle covers the bulb of the penis and contributes to erection, ejaculation, and urination. The muscle facilitates urination by compressing the bulb of the penis and the deep dorsal vein, blocking venous drainage and leading to an erection. The bulbocavernosus muscle also surrounds the corpus spongiosum and urethra and has its origin on the central perineal tendon. In females, the bulbocavernosus muscle covers the vestibular bulbs and contributes to clitoral erection and vaginal contractions during orgasm. It also helps to empty the greater vestibular glands by constricting the vaginal orifice.
The bulbocavernosus muscle is sexually dimorphic, meaning it differs between sexes. In males, it is wrapped around the bulb of the penis and the corpus spongiosum, while in females, it encircles the vaginal orifice. The function of this muscle is based on its compressive actions upon the erectile tissues it surrounds. The motoneurons that innervate the bulbocavernosus muscle are located in a cell group in the sacral spinal cord known as Onuf's nucleus, and there are more of these motoneurons in males than in females.
The bulbocavernosus muscle can be accessed through needle insertion medial to the labia minora or through the skin lateral to the labia majora. It is an integral part of the external anal sphincter (EAS) and plays a dual role in fecal control and sexual response. Disorders of the EAS are associated with sexual dysfunction. The bulbocavernosus reflex, also known as the penilo-cavernosus reflex, assesses the sacral root afferent and efferent pathways by electrically stimulating the dorsal nerve of the penis or clitoris and recording the response from the bulbocavernosus muscle.
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The muscle is involved in erections and ejaculation
The bulbocavernosus muscle (also known as the bulbospongiosus muscle) is a muscle of the perineum—the area between the anus and the genitals. The muscle is involved in erections and ejaculation in males and clitoral erections and orgasms in females.
In males, the bulbocavernosus muscle surrounds the bulb of the penis and contributes to erections and ejaculation. The muscle helps to compress the crus during erection, trapping blood in the corpora cavernosa and maintaining penile rigidity. It also increases pressure within the corpus spongiosum, further supporting firmness. During ejaculation, the bulbocavernosus muscle contracts rhythmically, creating waves of pressure to propel semen through the urethra.
In females, the bulbocavernosus muscle is divided into halves that extend from just behind the clitoris to the central tendon of the perineum. It contributes to clitoral erections and the contractions of orgasm. The muscle also closes the vagina.
The bulbocavernosus muscle is innervated by the perineal branch of the pudendal nerve. Dysfunction of the bulbocavernosus muscle can lead to significant challenges in male sexual function, but pelvic floor therapy offers effective solutions. Strengthening, relaxing, and improving the muscle coordination can help individuals regain control over their sexual health and enhance their quality of life.
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It is also known as the bulbospongiosus muscle
The bulbocavernosus muscle is also known as the bulbospongiosus muscle. In males, it is a muscle that surrounds the base of the penis and is directly related to erectile dysfunction. It is innervated by the perineal branch of the pudendal nerve. The bulbospongiosus muscle is a subgroup of the superficial muscles of the perineum.
In males, the bulbospongiosus muscle covers the bulb of the penis, while in females, it covers the vestibular bulbs. In both sexes, it is innervated by the deep or muscular branch of the perineal nerve, a branch of the pudendal nerve. The bulbospongiosus muscle is located in the middle line of the perineum, in front of the anus. It consists of two symmetrical parts, united along the median line by a tendinous perineal raphe.
In males, the bulbospongiosus muscle contributes to erection, the contractions of orgasm and ejaculation. It also serves to empty the canal of the urethra after the bladder has expelled its contents. The middle fibres assist in the erection of the corpus spongiosum by compressing the erectile tissue of the bulb. The anterior fibres contribute to the erection of the penis by compressing the deep dorsal vein of the penis as they are inserted into, and continuous with, the fascia of the penis.
In females, the bulbospongiosus muscle contributes to clitoral erection and the contractions of orgasm, and closes the vagina. It also serves to empty the canal of the urethra after the bladder has expelled its contents.
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Frequently asked questions
The bulbocavernosus muscle is located in the perineum, the area between the anus and the genitals. It surrounds the base of the penis and is directly related to erectile dysfunction in men.
In females, the bulbocavernosus muscle is divided into halves that extend from just behind the clitoris to the central tendon of the perineum. It serves to constrict the vagina.
The function of the bulbocavernosus muscle is based on its compressive actions upon the erectile tissues which it surrounds. In males, it facilitates urination, ejaculation, and erection. In females, it contributes to clitoral erection and the contractions of orgasm, and closes the vagina.
