Perineum
Updates to Article Attributes
The perineum is a diamond-shaped region below the pelvic diaphragm and is divided by an imaginary line drawn between the ischial tuberosities into anteriorly the urogenital triangle and posteriorly the anal triangle.
Gross anatomy
The perineum is bounded by the pubis anteriorly, the ischial tuberosities anterolaterally, the sacrotuberous ligaments posterolaterally and the coccyx posteriorly.
The urogenital triangle is the anterior part of the perineum and it contains the penis and scrotum in males and mons pubis, labia majora and minora, clitoris and vaginal and urethral orifices in females. A sheet of fascia covers the urogenital diaphragm inferiorly, the perineal membrane, which divides the urogenital triangle into the deep perineal pouch superior (deep) to the membrane and the superficial perineal pouch inferior (superficial) to the membrane. The perineal membrane is less conspicuous in females.
The anal triangle contains the anus and its sphincters and also the ischioanal fossaon either side in both males and females.
The central tendon of the perineum is the midpoint of the joining line between the ischial tuberosities and is called the perineal body. The perineal body lies behind the vagina in females and supports the vagina against prolapse. The anal sphincters, bulbospongiosus muscle, superficial and deep transverse perineal muscles and levator ani muscles are attached toform a close anatomic relationship with the perineal body in the midline.
Arterial supply
The internal pudendal artery is a branch of the internal iliac artery and is the main supplier of the perineum.
Innervation
The pudendal nerve (S2 to S4), and its branches, are the nerves of the perineum and pelvic floor.
Radiographic features
Imaging is required to assess pelvic floor laxity in women with urinary and bowel continence issues.
CT
Provides limited visualisation of the pelvic muscles.
MRI
Muscles of the pelvic floor can be imaged with MRI and pelvic floor movements can be assessed with dynamic MRI.
MRI is the modality of choice in assessing the complex perineal lesions and their relations to the adjacent structures. It provides guidance for surgical planning due to its greater sensitivity and specificity than the other non-invasive imaging techniques.
-<p>The <strong>perineum </strong>is a diamond-shaped region below the <a href="/articles/levator-ani-muscle">pelvic diaphragm</a> and is divided by an imaginary line drawn between the <a href="/articles/ischium">ischial tuberosities</a> into anteriorly the <a href="/articles/urogenital-triangle">urogenital triangle</a> and posteriorly the <a href="/articles/anal-triangle">anal triangle</a>.</p><h4>Gross anatomy</h4><p>The perineum is bounded by the <a href="/articles/pubis">pubis</a> anteriorly, the <a href="/articles/ischium">ischial tuberosities</a> anterolaterally, the <a href="/articles/sacrotuberous-ligament">sacrotuberous ligaments</a> posterolaterally and the <a href="/articles/coccyx">coccyx</a> posteriorly.</p><p>The <strong>urogenital triangle </strong>is the anterior part of the perineum and it contains the <a href="/articles/penis">penis </a>and <a href="/articles/scrotum">scrotum</a> in males and <a href="/articles/mons-pubis">mons pubis</a>, <a href="/articles/labia-majora">labia majora</a> and <a href="/articles/labia-minora">minora</a>, <a href="/articles/clitoris">clitoris</a> and <a href="/articles/vaginal-opening">vaginal </a>and <a href="/articles/female-urethra">urethral orifices</a> in females. A sheet of fascia covers the urogenital diaphragm inferiorly, the <a href="/articles/perineal-membrane">perineal membrane</a>, which divides the urogenital triangle into the <a href="/articles/deep-perineal-pouch">deep perineal pouch</a> superior (deep) to the membrane and the <a href="/articles/superficial-perineal-pouch">superficial perineal pouch</a> inferior (superficial) to the membrane. The perineal membrane is less conspicuous in females.</p><p>The <strong>anal triangle</strong> contains the <a href="/articles/anus">anus</a> and its <a href="/articles/anal-sphincter-1">sphincters</a> and also the <a href="/articles/ischioanal-fossa">ischioanal fossa</a><a href="/articles/ischioanal-fossa"> </a>on either side in both males and females.</p><p>The central tendon of the perineum is the midpoint of the joining line between the ischial tuberosities and is called the <strong>perineal body</strong>. The <a title="perineal body" href="/articles/perineal-body">perineal body</a> lies behind the <a href="/articles/vagina">vagina</a> in females and supports the vagina against prolapse. The <a href="/articles/anal-sphincter-1">anal sphincters</a>, <a href="/articles/bulbospongiosus-muscle">bulbospongiosus muscle</a>, <a href="/articles/superficial-transverse-perineal-muscle">superficial</a> and <a href="/articles/deep-transverse-perineal-muscles">deep transverse perineal muscles</a> and <a href="/articles/levator-ani-muscle">levator ani muscles</a> are attached to the perineal body in the midline.</p><h4>Arterial supply</h4><p>The <a href="/articles/internal-pudendal-artery-1">internal pudendal artery</a> is a branch of the <a href="/articles/internal-iliac-artery">internal iliac artery</a> and is the main supplier of the perineum.</p><h4>Innervation</h4><p>The <a href="/articles/pudendal-nerve-1">pudendal nerve</a> (S2 to S4), and its branches, are the nerves of the perineum and pelvic floor.</p><h4>Radiographic features</h4><p>Imaging is required to assess pelvic floor laxity in women with urinary and bowel continence issues.</p><h5>CT</h5><p>Provides limited visualisation of the pelvic muscles.</p><h5>MRI</h5><p>Muscles of the pelvic floor can be imaged with MRI and pelvic floor movements can be assessed with <a href="/articles/mr-defaecating-proctography">dynamic MRI</a>.</p><p>MRI is the modality of choice in assessing the complex perineal lesions and their relations to the adjacent structures. It provides guidance for surgical planning due to its greater sensitivity and specificity than the other non-invasive imaging techniques.</p>- +<p>The <strong>perineum </strong>is a diamond-shaped region below the <a href="/articles/levator-ani-muscle">pelvic diaphragm</a> and is divided by an imaginary line drawn between the <a href="/articles/ischium">ischial tuberosities</a> into anteriorly the <a href="/articles/urogenital-triangle">urogenital triangle</a> and posteriorly the <a href="/articles/anal-triangle">anal triangle</a>.</p><h4>Gross anatomy</h4><p>The perineum is bounded by the <a href="/articles/pubis">pubis</a> anteriorly, the <a href="/articles/ischium">ischial tuberosities</a> anterolaterally, the <a href="/articles/sacrotuberous-ligament">sacrotuberous ligaments</a> posterolaterally and the <a href="/articles/coccyx">coccyx</a> posteriorly.</p><p>The <strong>urogenital triangle </strong>is the anterior part of the perineum and it contains the <a href="/articles/penis">penis </a>and <a href="/articles/scrotum">scrotum</a> in males and <a href="/articles/mons-pubis">mons pubis</a>, <a href="/articles/labia-majora">labia majora</a> and <a href="/articles/labia-minora">minora</a>, <a href="/articles/clitoris">clitoris</a> and <a href="/articles/vaginal-opening">vaginal </a>and <a href="/articles/female-urethra">urethral orifices</a> in females. A sheet of fascia covers the urogenital diaphragm inferiorly, the <a href="/articles/perineal-membrane">perineal membrane</a>, which divides the urogenital triangle into the <a href="/articles/deep-perineal-pouch">deep perineal pouch</a> superior (deep) to the membrane and the <a href="/articles/superficial-perineal-pouch">superficial perineal pouch</a> inferior (superficial) to the membrane. The perineal membrane is less conspicuous in females.</p><p>The <strong>anal triangle</strong> contains the <a href="/articles/anus">anus</a> and its <a href="/articles/anal-sphincter-1">sphincters</a> and also the <a href="/articles/ischioanal-fossa">ischioanal fossa</a><a href="/articles/ischioanal-fossa"> </a>on either side in both males and females.</p><p>The central tendon of the perineum is the midpoint of the joining line between the ischial tuberosities and is called the <strong>perineal body</strong>. The <a href="/articles/perineal-body">perineal body</a> lies behind the <a href="/articles/vagina">vagina</a> in females and supports the vagina against prolapse. The <a href="/articles/anal-sphincter-1">anal sphincters</a>, <a href="/articles/bulbospongiosus-muscle">bulbospongiosus muscle</a>, <a href="/articles/superficial-transverse-perineal-muscle">superficial</a> and <a href="/articles/deep-transverse-perineal-muscles">deep transverse perineal muscles</a> and <a href="/articles/levator-ani-muscle">levator ani muscles</a> form a close anatomic relationship with the perineal body in the midline.</p><h4>Arterial supply</h4><p>The <a href="/articles/internal-pudendal-artery-1">internal pudendal artery</a> is a branch of the <a href="/articles/internal-iliac-artery">internal iliac artery</a> and is the main supplier of the perineum.</p><h4>Innervation</h4><p>The <a href="/articles/pudendal-nerve-1">pudendal nerve</a> (S2 to S4), and its branches, are the nerves of the perineum and pelvic floor.</p><h4>Radiographic features</h4><p>Imaging is required to assess pelvic floor laxity in women with urinary and bowel continence issues.</p><h5>CT</h5><p>Provides limited visualisation of the pelvic muscles.</p><h5>MRI</h5><p>Muscles of the pelvic floor can be imaged with MRI and pelvic floor movements can be assessed with <a href="/articles/mr-defaecating-proctography">dynamic MRI</a>.</p><p>MRI is the modality of choice in assessing the complex perineal lesions and their relations to the adjacent structures. It provides guidance for surgical planning due to its greater sensitivity and specificity than the other non-invasive imaging techniques.</p>
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