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Pelvic cavity
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<h2 id="structure">Structure</h2> <p>The pelvis has an anteroinferior, a posterior, and two lateral pelvic walls; and an inferior pelvic wall, also called the <a href="/facts/Pelvic_floor/PRXFuM1U">pelvic floor</a>.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a><a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a> The <a href="/facts/Parietal_peritoneum/BotJhUr0">parietal peritoneum</a> is attached here and to the <a href="/facts/Abdominal_wall/AEEQ1Fmr">abdominal wall</a>.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a> </p> <h3>Lesser pelvis</h3> <p>The lesser pelvis (or "true pelvis") is the space enclosed by the <a href="/facts/Pelvic_girdle/8Fq9z3TY">pelvic girdle</a> and below the <a href="/facts/Pelvic_brim/lP7au9EC">pelvic brim</a>: between the <a href="/facts/Pelvic_inlet/KAjsY6vc">pelvic inlet</a> and the pelvic floor. This cavity is a short, curved canal, deeper on its posterior than on its anterior wall.<a class="footnote-ref" id="fnref:6" href="#fn:6"><sup>6</sup></a> Some sources consider this region to be the entirety of the pelvic cavity. Other sources define the pelvic cavity as the larger space including the greater pelvis, just above the pelvic inlet. </p><p>The lesser pelvis is bounded in front and below by the <a href="/facts/Pubic_symphysis/voKAVNqB">superior rami of the symphysis pubis</a>; above and behind, by the sacrum and coccyx; and laterally, by a broad, smooth, quadrangular area of bone, corresponding to the inner surfaces of the body and superior ramus of the <a href="/facts/Ischium/hfj1UDwx">ischium</a>, and the part of the <a href="/facts/Ilium_(bone)/4zEB7NX0">ilium</a> below the <a href="/facts/Arcuate_line_(ilium)/CS55noJV">arcuate line</a>.<a class="footnote-ref" id="fnref:7" href="#fn:7"><sup>7</sup></a> </p> <table><tbody><tr><td colspan="3"> roof: <a href="/facts/Pelvic_brim/lP7au9EC">pelvic brim</a><a class="footnote-ref" id="fnref:8" href="#fn:8"><sup>8</sup></a> </td></tr><tr><td> posterior: <a href="/facts/Sacrum/CTFnjSm0">sacrum</a>, <a href="/facts/Coccyx/BQ2qjXwg">coccyx</a> </td><td> lateral: <a href="/facts/Obturator_internus/YK4TGb3j">obturator internus</a> </td><td> anterior: <a href="/facts/Pubic_symphysis/voKAVNqB">pubic symphysis</a> </td></tr><tr><td colspan="3">floor: pelvic floor </td></tr></tbody></table> <p>The lesser pelvis contains the <a href="/facts/Pelvic_colon/vdrXYrG4">pelvic colon</a>, <a href="/facts/Rectum/caqqyk2e">rectum</a>, <a href="/facts/Urinary_bladder/g8Khaf7A">bladder</a>, and some of the <a href="/facts/Sex_organ/c2ypY14E">sex organs</a>. The rectum is at the back, in the curve of the <a href="/facts/Sacrum/CTFnjSm0">sacrum</a> and <a href="/facts/Coccyx/BQ2qjXwg">coccyx</a>; the bladder is in front, behind the <a href="/facts/Pubic_symphysis/voKAVNqB">pubic symphysis</a>. In females, the <a href="/facts/Uterus/LIrApMXs">uterus</a> and <a href="/facts/Vagina/ca5jsTwF">vagina</a> occupy the interval between these viscera.<a class="footnote-ref" id="fnref:9" href="#fn:9"><sup>9</sup></a> </p><p>The <a href="/facts/Pelvic_splanchnic_nerves/myS8z3lz">pelvic splanchnic nerves</a> arising at S2–S4 are in the lesser pelvis. </p> <h3>Greater pelvis</h3> <p>The greater pelvis (or false pelvis) is the space enclosed by the <a href="/facts/Pelvic_girdle/8Fq9z3TY">pelvic girdle</a> above and in front of the <a href="/facts/Pelvic_brim/lP7au9EC">pelvic brim</a>. It is bounded on either side by the <a href="/facts/Ilium_(bone)/4zEB7NX0">ilium</a>. In the front, it is incomplete, presenting a wide interval between the anterior borders of the <a href="/facts/Ilium_(bone)/4zEB7NX0">ilia</a>, which is filled by the muscles and fascia of the <a href="/facts/Anterior_abdominal_wall/AEEQ1Fmr">anterior abdominal wall</a>; behind is a deep notch on either side between the ilium and the <a href="/facts/Base_of_the_sacrum/CTFnjSm0">base of the sacrum</a> that is filled by the <a href="/facts/Thoracolumbar_fascia/oderqLIo">thoracolumbar fascia</a> and associated muscles.<a class="footnote-ref" id="fnref:10" href="#fn:10"><sup>10</sup></a> </p><p>It is generally considered part of the <a href="/facts/Abdominal_cavity/S2XdDfFv">abdominal cavity</a> (which is why it is sometimes called the false pelvis).<a class="footnote-ref" id="fnref:11" href="#fn:11"><sup>11</sup></a> Some sources consider this region part of the pelvic cavity, while others reframe the classification by calling the combination the <a href="/facts/Abdominopelvic_cavity/tIf4HjPa">abdominopelvic cavity</a>. </p><p>The greater pelvis supports the <a href="/facts/Intestines/nK2zwqBS">intestines</a> (specifically, the <a href="/facts/Ileum/rCWGkFuf">ileum</a> and <a href="/facts/Sigmoid_colon/vdrXYrG4">sigmoid colon</a>), and transmits part of their weight to the anterior wall of the <a href="/facts/Abdomen/HcTzDFL0">abdomen</a>.<a class="footnote-ref" id="fnref:12" href="#fn:12"><sup>12</sup></a> </p><p>The <a href="/facts/Femoral_nerve/ojdewxlV">femoral nerve</a> from L2–L4 is in the greater pelvis, but not in the lesser pelvis. </p> <h3>Ligaments</h3> <table><tbody><tr><th>Ligament</th><th>From</th><th>To</th></tr><tr><td><a href="/facts/Broad_ligament_of_the_uterus/zXx3ISKo">broad ligament of the uterus</a></td><td>uterus</td><td>side of pelvis</td></tr><tr><td>* <a href="/facts/Mesovarium/PKHvEErJ">mesovarium</a></td><td><a href="/facts/Ovary/z2hG6bNy">ovary</a></td><td></td></tr><tr><td>* <a href="/facts/Mesosalpinx/JL3GoeKE">mesosalpinx</a></td><td><a href="/facts/Fallopian_tube/oyRcvAxE">Fallopian tube</a></td><td><a href="/facts/Broad_ligament_of_the_uterus/zXx3ISKo">broad ligament of the uterus</a></td></tr><tr><td>* <a href="/facts/Mesometrium/84A8RWRk">mesometrium</a></td><td></td><td></td></tr><tr><td><a href="/facts/Cardinal_ligament/XIub2KLc">cardinal ligament</a></td><td>cervix and vagina</td><td>pelvic wall</td></tr><tr><td><a href="/facts/Ovarian_ligament/7Xojp7cP">ovarian ligament</a></td><td>ovary</td><td>uterus</td></tr><tr><td><a href="/facts/Round_ligament_of_the_uterus/fQl1b5VD">round ligament of the uterus</a></td><td>ovary</td><td>travels through inguinal canal, ends at mons pubis</td></tr><tr><td><a href="/facts/Suspensory_ligament_of_the_ovary/oUre6hqg">suspensory ligament of the ovary</a></td><td>ovary</td><td>pelvic wall</td></tr></tbody></table> <h3>Arteries</h3> <ul><li><a href="/facts/Internal_iliac_artery/XKU7cRw9">internal iliac artery</a></li> <li><a href="/facts/Median_sacral_artery/MDsm8sda">median sacral artery</a></li> <li><a href="/facts/Ovarian_artery/qhkCJENB">ovarian artery</a></li></ul> <h3>Nerves</h3> <ul><li><a href="/facts/Sacral_plexus/6HVyBl1m">sacral plexus</a></li> <li><a href="/facts/Splanchnic_nerves/atDFXxVV">splanchnic nerves</a></li> <li><a href="/facts/Femoral_nerve/ojdewxlV">femoral nerve</a> (greater pelvis)</li></ul> <h2 id="measurements">Measurements</h2> <p>The pelvis can be classified into four main types by measuring the pelvic diameters and conjugates at the pelvic inlet and outlet and as oblique diameters. </p> Pelvic measurements<a class="footnote-ref" id="fnref:13" href="#fn:13"><sup>13</sup></a><table><tbody><tr><th>Measurement</th><th>From</th><th>To</th><th>Length</th></tr><tr><td>Transverse diameter(of inlet)</td><td colspan="2">Between extreme lateral points of pelvic inlet</td><td>13.5–14 cm</td></tr><tr><td>Oblique diameter I</td><td>Right <a href="/facts/Sacroiliac_joint/XgpSo3YP">sacroiliac joint</a></td><td>Left iliopubic eminence</td><td>12-12.5 cm</td></tr><tr><td>Oblique diameter II</td><td>Left sacroiliac joint</td><td>Right iliopubic eminence</td><td>11.5–12 cm</td></tr><tr><td>Anatomical conjugate(true conjugate)</td><td>Pubic symphysis</td><td>Promontory</td><td>~12 cm</td></tr><tr><td>Obstetric conjugate</td><td>Retropubic eminence(posterior surfaceof symphysis)</td><td>Promontory</td><td>>10 cm</td></tr><tr><td>Diagonal conjugate*</td><td>Inferior pubic ligament</td><td>Promontory</td><td>11.5–12 cm</td></tr><tr><td>Straight conjugate</td><td>Lower border of symphysis</td><td>Tip of coccyx</td><td>9.5–10 cm</td></tr><tr><td>Median conjugate</td><td>Lower border of symphysis</td><td>Lower border of sacrum</td><td>11.5 cm</td></tr><tr><td>Transverse diameter(of outlet)</td><td colspan="2">Between <a href="/facts/Ischial_tuberosities/mbuJnvNt">ischial tuberosities</a></td><td>10–11 cm</td></tr><tr><td>Interspinous distance</td><td colspan="2">Between anterior superior iliac spines</td><td>26 cm(female)</td></tr><tr><td>Intercristal distance</td><td colspan="2">Between furthest lateral points of <a href="/facts/Iliac_crest/VtJo4smJ">iliac crest</a></td><td>29 cm(female)</td></tr><tr><td>External conjugate</td><td>Spinous process of fifth lumbar vertebra</td><td>Upper edge of symphysis</td><td>~20 cm</td></tr><tr><td>Intertrochanteric distance</td><td colspan="2">Between femurs</td><td>31 cm</td></tr><tr><td colspan="4">Because the true conjugate cannot be measured directly, it is derived from the diagonal conjugate, which is measured through the vagina.</td></tr></tbody></table> <h2 id="additional-images">Additional images</h2> <h2 id="external-links">External links</h2> <ul><li><a href="https://web.archive.org/web/20170604111136/http://www.smbs.buffalo.edu/ana/newpage45.htm">Overview at buffalo.edu</a></li> <li><a href="http://faculty.southwest.tn.edu/rburkett/human_20.jpg">Diagram at southwest.tn.edu</a></li> <li><a href="http://www.changbioscience.com/store/images/anatomical/smd070/smd0703.htm">Photo of model (female)</a></li> <li><a href="http://ect.downstate.edu/courseware/haonline/labs/l44/os0502.htm">Anatomy photo:44:os-0502</a> at the SUNY Downstate Medical Center – "The Male Pelvis: Articulated bones of male pelvis"</li> <li><a href="http://ect.downstate.edu/courseware/haonline/labs/l44/os0503.htm">Anatomy photo:44:os-0503</a> at the SUNY Downstate Medical Center</li></ul> <h2 id="references">References</h2> <ol> <li id="fn:1"><p>This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) <a href="/wiki/Public_domain" target="_blank">/wiki/Public_domain</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li> <li id="fn:2"><p>Drake R, Vogl AW, Mitchell AW (2018). "5 Pelvis and Perineum". Gray's Basic Anatomy E-Book. Elsevier. pp. 220–227. ISBN 978-0-323-50850-6.{{cite book}}: CS1 maint: multiple names: authors list (link) <a href="978-0-323-50850-6" target="_blank">978-0-323-50850-6</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li> <li id="fn:3"><p>Moore, Keith L. et al. (2010) Clinically Oriented Anatomy 6th Ed, ch. 3 Pelvis and perineum, p. 339 <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li> <li id="fn:4"><p>Richard S. Snell Clinical Anatomy By Regions, Pelvic cavity p. 242 <a href="https://books.google.com/books?id=vb4AcUL4CE0C&pg=PA242" target="_blank">https://books.google.com/books?id=vb4AcUL4CE0C&pg=PA242</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li> <li id="fn:5"><p>Tank, P. (2013) Grants Dissector 15th ed., ch. 4 The abdomen, p. 99 <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li> <li id="fn:6"><p>This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) <a href="/wiki/Public_domain" target="_blank">/wiki/Public_domain</a> <a href="#fnref:6" class="footnote-back-ref">↩</a></p></li> <li id="fn:7"><p>This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) <a href="/wiki/Public_domain" target="_blank">/wiki/Public_domain</a> <a href="#fnref:7" class="footnote-back-ref">↩</a></p></li> <li id="fn:8"><p>"Anatomy of the Female Pelvis – D. El-Mowafi". Retrieved 2007-12-03. <a href="http://www.gfmer.ch/Obstetrics_simplified/anatomy_of_the_female_pelvis.htm" target="_blank">http://www.gfmer.ch/Obstetrics_simplified/anatomy_of_the_female_pelvis.htm</a> <a href="#fnref:8" class="footnote-back-ref">↩</a></p></li> <li id="fn:9"><p>This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) <a href="/wiki/Public_domain" target="_blank">/wiki/Public_domain</a> <a href="#fnref:9" class="footnote-back-ref">↩</a></p></li> <li id="fn:10"><p>This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) <a href="/wiki/Public_domain" target="_blank">/wiki/Public_domain</a> <a href="#fnref:10" class="footnote-back-ref">↩</a></p></li> <li id="fn:11"><p>Drake et al. (2009) Grays Anatomy for Students, 2nd Edition, ch. 5 Pelvis and perineum – general description, p. 406 <a href="#fnref:11" class="footnote-back-ref">↩</a></p></li> <li id="fn:12"><p>This article incorporates text in the public domain from the 20th edition of Gray's Anatomy (1918) <a href="/wiki/Public_domain" target="_blank">/wiki/Public_domain</a> <a href="#fnref:12" class="footnote-back-ref">↩</a></p></li> <li id="fn:13"><p>Platzer, Werner (2004). Color Atlas of Human Anatomy, Vol. 1: Locomotor System (5th ed.). Thieme. p. 190. ISBN 3-13-533305-1. <a href="3-13-533305-1" target="_blank">3-13-533305-1</a> <a href="#fnref:13" class="footnote-back-ref">↩</a></p></li> </ol>