Pyramidalis muscle

<h2 id="structure">Structure</h2>
<p>The pyramidalis muscle is part of the anterior abdominal wall.<a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a> Inferiorly, the pyramidalis muscle attaches to the <a href="/facts/Pelvis/8Fq9z3TY">pelvis</a> in two places: the <a href="/facts/Pubic_symphysis/voKAVNqB">pubic symphysis</a> and <a href="/facts/Pubic_crest/11MQpadK">pubic crest</a>, arising by tendinous fibers from the anterior part of the <a href="/facts/Pubis_(bone)/4gU0dgIy">pubis</a> and the <a href="/facts/Pubic_symphysis/voKAVNqB">anterior pubic ligament</a>.
</p><p>Superiorly, the fleshy portion of the pyramidalis muscle passes upward, diminishing in size as it ascends, and ends by a pointed extremity which is inserted into the <a href="/facts/Linea_alba_(abdomen)/3NVQ8kkK">linea alba</a>, midway between the <a href="/facts/Navel/ICl77Nwb">umbilicus</a> and <a href="/facts/Pubis_(bone)/4gU0dgIy">pubis</a>.
</p>
<h3>Nerve supply</h3>
<p>The pyramidalis muscle is innervated by the ventral portion of <a href="/facts/Thoracic_spinal_nerve_12/vFHMoFLh">T12</a>.
</p>
<h3>Blood supply</h3>
<p>The <a href="/facts/Inferior_epigastric_artery/kCyANLxw">inferior</a> and <a href="/facts/Superior_epigastric_artery/rt59kasw">superior epigastric arteries</a> supply blood to the pyramidalis muscle.
</p>
<h3>Variation</h3>
<p>The pyramidalis muscle is present in 80% of human population.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a>[<i>unreliable source?</i>] It may be absent on one or both sides; the lower end of the rectus then becomes proportionately increased in size.
</p><p>Occasionally, it is doubled on one side, and the muscles of the two sides are sometimes of unequal size. It may also extend higher than the usual level.
</p>
<h2 id="function">Function</h2>
<p>The pyramidalis muscle tenses the <a href="/facts/Linea_alba_(abdomen)/3NVQ8kkK">linea alba</a> when contracting.
</p>
<h2 id="clinical-significance">Clinical significance</h2>
<p>While making the longitudinal incision for a classical <a href="/facts/Caesarean_section/GJ623ers">caesarean section</a>, the pyramidalis muscle is used to determine midline and location of the <a href="/facts/Linea_alba_(abdomen)/3NVQ8kkK">linea alba</a>.
</p>
<h2 id="additional-images">Additional images</h2>

<h2 id="external-links">External links</h2>
<ul><li><a href="http://ect.downstate.edu/courseware/haonline/labs/l35/110100.htm">Anatomy photo:35:11-0100</a> at the SUNY Downstate Medical Center - "Anterior Abdominal Wall: The Pyramidalis Muscle"</li>
<li><a href="http://ect.downstate.edu/courseware/haonline/imgs/00000/7000/200/7283.jpg">Anatomy image:7283</a> at the SUNY Downstate Medical Center</li>
<li><a href="https://www.meduniwien.ac.at/plastination/pelvis/pelvis-female-17-text.html">Cross section image: pelvis/pelvis-female-17</a>—Plastination Laboratory at the Medical University of Vienna</li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Shapiro, L. E.; Kim, J. H.; Lee, S. J.; Yoo, J. J.; Atala, A.; Ko, I. K. (2016-01-01), Lee, Sang Jin; Yoo, James J.; Atala, Anthony (eds.), "Chapter 16 - In Situ Volumetric Muscle Repair", In Situ Tissue Regeneration, Boston: Academic Press, pp. 295–312, ISBN 978-0-12-802225-2, retrieved 2021-01-23 <a href="978-0-12-802225-2" target="_blank">978-0-12-802225-2</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>"7 Vestigial Features of the Human Body". Encyclopedia Britannica. Retrieved 2017-11-09. <a href="https://www.britannica.com/list/7-vestigial-features-of-the-human-body" target="_blank">https://www.britannica.com/list/7-vestigial-features-of-the-human-body</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
</ol>

Pyramidalis muscle open-in-new

Pyramidalis muscle