Transverse perineal muscles | |
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Details | |
Origin | Inferior rami of the ischium |
Insertion | The deep transverse perineal muscle of the opposite side |
Nerve | Pudendal nerve |
Actions | Constricts urethra and vagina, maintains urinary continence |
Identifiers | |
Latin | musculus transversus perinei profundus, musculus transversus superficialis perinei |
Anatomical terms of muscle |
The transverse perineal muscles (transversus perinei) are the superficial and the deep transverse perineal muscles.
The superficial transverse perineal muscle (transversus superficialis perinei or Lloyd-Beanie muscle) is a narrow muscular slip, which passes more or less transversely across the perineal space in front of the anus. [1]
It arises by tendinous fibers from the inner and forepart of the ischial tuberosity and, running medially, is inserted into the central tendinous point of the perineum (perineal body), joining in this situation with the muscle of the opposite side, with the external anal sphincter muscle behind, and with the bulbospongiosus muscle in front.
In some cases, the fibers of the deeper layer of the external anal sphincter cross over in front of the anus and are continued into this muscle. Occasionally it gives off fibers, which join with the bulbocavernosus of the same side.
There are some variations: it may be absent or double, or insert into the bulbocavernosus or the external sphincter.
The deep transverse perineal muscle (transversus perinei profundus) lies in the perineum, a part of the pelvic floor. It arises from the inferior rami of the ischium and runs to the median plane, where it interlaces in a tendinous raphe with the other deep transverse perineal muscle of the opposite side.
The deep transverse perineal muscle is innervated by the pudendal nerve. The function of the muscle is fixation of the perineal body (central tendon of perineum), support of the pelvic floor, expulsion of semen in males and last drops of urine in both sexes. [2]
The deep transverse perineal muscle lies in the same plane as the urethral sphincter and formerly the two muscles were described together as the constrictor urethrae.
The perineum in humans is the space between the anus and scrotum in the male, or between the anus and the vulva in the female. The perineum is the region of the body between the pubic symphysis and the coccyx, including the perineal body and surrounding structures. The perineal raphe is visible and pronounced to varying degrees. The perineum is an erogenous zone. This area is also known as the taint or chode in American slang.
The levator ani is a broad, thin muscle group, situated on either side of the pelvis. It is formed from three muscle components: the pubococcygeus, the iliococcygeus, and the puborectalis.
The ischiocavernosus muscle is a muscle just below the surface of the perineum, present in both men and women.
The bulbospongiosus muscle is one of the superficial muscles of the perineum. It has a slightly different origin, insertion and function in males and females. In males, it covers the bulb of the penis. In females, it covers the vestibular bulb.
The internal pudendal artery is one of the three pudendal arteries. It branches off the internal iliac artery, and provides blood to the external genitalia.
The internal obturator muscle or obturator internus muscle originates on the medial surface of the obturator membrane, the ischium near the membrane, and the rim of the pubis.
The transverse abdominal muscle (TVA), also known as the transverse abdominis, transversalis muscle and transversus abdominis muscle, is a muscle layer of the anterior and lateral abdominal wall, deep to the internal oblique muscle. It is thought by most fitness instructors to be a significant component of the core.
The transversus thoracis muscle, also known as triangularis sterni, lies internal to the thoracic cage, anteriorly. It is usually a thin plane of muscular and tendinous fibers, however on athletic individuals it can be a thick 'slab of meat', situated upon the inner surface of the front wall of the chest. It is in the same layer as the subcostal muscles and the innermost intercostal muscles.
The external anal sphincter is an oval tube skeletal muscle fibers. Distally, it is adherent to the skin surrounding the margin of the anus. The sphincter exhibits a resting state of tonical contraction.
The external sphincter muscle of male urethra, also sphincter urethrae membranaceae, sphincter urethrae externus, surrounds the whole length of the membranous urethra, and is enclosed in the fascia of the urogenital diaphragm.
The gracilis muscle is the most superficial muscle on the medial side of the thigh. It is thin and flattened, broad above, narrow and tapering below.
The inferior rectal artery is an artery that supplies blood to the lower third of the anal canal below the pectinate line.
The perineal nerve is a nerve of the pelvis. It arises from the pudendal nerve in the pudendal canal. It gives superficial branches to the skin, and a deep branch to muscles. It supplies the skin and muscles of the perineum. Its latency is tested with electrodes.
The Inferior rectal nerves usually branch from the pudendal nerve but occasionally arises directly from the sacral plexus; they cross the ischiorectal fossa along with the inferior rectal artery and veins, toward the anal canal and the lower end of the rectum, and is distributed to the Sphincter ani externus and to the integument (skin) around the anus.
The deep perineal pouch is the anatomic space enclosed in part by the perineum, and located superior to the perineal membrane.
The urogenital triangle is the anterior part of the perineum. In female mammals, it contains the vagina and associated parts of the internal genitalia.
The anal triangle is the posterior part of the perineum. It contains the anal canal.
The deep branch of the perineal nerve is a nerve of the perineum. It is a branch of the perineal nerve, from the pudendal nerve. It supplies the superficial transverse perineal muscle, bulbospongiosus muscle, ischiocavernosus muscle, the bulb of penis, levator ani, and the external anal sphincter.
A perineal tear is a laceration of the skin and other soft tissue structures which, in women, separate the vagina from the anus. Perineal tears mainly occur in women as a result of vaginal childbirth, which strains the perineum. It is the most common form of obstetric injury. Tears vary widely in severity. The majority are superficial and may require no treatment, but severe tears can cause significant bleeding, long-term pain or dysfunction. A perineal tear is distinct from an episiotomy, in which the perineum is intentionally incised to facilitate delivery. Episiotomy, a very rapid birth, or large fetal size can lead to more severe tears which may require surgical intervention.
The vaginal support structures are those muscles, bones, ligaments, tendons, membranes and fascia, of the pelvic floor that maintain the position of the vagina within the pelvic cavity and allow the normal functioning of the vagina and other reproductive structures in the female. Defects or injuries to these support structures in the pelvic floor leads to pelvic organ prolapse. Anatomical and congenital variations of vaginal support structures can predispose a woman to further dysfunction and prolapse later in life. The urethra is part of the anterior wall of the vagina and damage to the support structures there can lead to incontinence and urinary retention.
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