Inferior mesenteric artery

Changed by Raymond Chieng, 31 Jan 2023

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The inferior mesenteric artery (IMA) is one of the three non-paired major splanchnic arteries, in the abdominal cavity, arising from the abdominal aorta and supplying the hindgut. It is the smallest of the three anterior visceral branches of the abdominal aorta.

Gross anatomy

Location

Located within the mesentery of the hindgut, passing to the left of the midline.

Origin

Unpaired vessel from the anterior aspect of the abdominal aorta at the L3 level, at the lower edge of the third part of duodenum⁵.

Course

The IMA runs obliquely downwards towards the pelvic brim, initially anterior and then to the left of the aorta. After giving off the left colic and sigmoid arteries, it crosses the origin of the left common iliac artery at the sacroiliac joint medial to the ureter, with the inferior mesenteric vein lying between the two. Within the pelvis, it continues along the pelvic wall as the superior rectal artery in the root of the sigmoid mesocolon.

Branches

left colic artery
two to four sigmoid arteries
superior rectal artery (terminal branch)

Supply

splenic flexure of large bowel to the upper two thirds of the rectum

Relations

anterior: third part of the duodenum
posterior: abdominal aorta, left psoas, sympathetic trunk, left common iliac artery, hypogastric nerve
lateral (left): inferior mesenteric vein

The inferior mesenteric plexus (autonomic plexus) lies at the origin of the IMA.

The left colic and sigmoid branches of the IMA cross anterior to the ureter.

Variant anatomy

doubled IMA
absent IMA
common trunks (e.g. left colic and rectosigmoid, rectal and colosigmoid)
absent left colic branch
Arc of Riolan (SMA/IMA connection)

-<p>The <strong>inferior mesenteric artery (IMA)</strong> is one of the three non-paired major <a href="/articles/viscera">splanchnic arteries</a>, in the <a href="/articles/abdominal-cavity">abdominal cavity</a>, arising from the <a href="/articles/abdominal-aorta-1">abdominal aorta</a> and supplying the hindgut. It is the smallest of the three anterior visceral branches of the abdominal aorta.</p><h4>Gross anatomy</h4><h5>Location</h5><p>Located within the mesentery of the hindgut, passing to the left of the midline.</p><h5>Origin</h5><p>Unpaired vessel from the anterior aspect of the <a href="/articles/abdominal-aorta-1">abdominal aorta</a> at the L3 level, at the lower edge of the third part of duodenum.</p><h5>Course</h5><p>The IMA runs obliquely downwards towards the pelvic brim, initially anterior and then to the left of the aorta. After giving off the left colic and sigmoid arteries, it crosses the origin of the left common iliac artery at the sacroiliac joint medial to the ureter, with the inferior mesenteric vein lying between the two. Within the pelvis, it continues along the pelvic wall as the superior rectal artery in the root of the sigmoid mesocolon.</p><h5>Branches</h5><ul>
~~-<li><a href="/articles/left-colic-artery">left colic artery</a></li>~~
~~-<li>two to four <a href="/articles/sigmoid-arteries">sigmoid arteries</a>~~
~~-</li>~~
~~-<li>~~
~~-<a href="/articles/superior-rectal-artery">superior rectal artery</a> (terminal branch)</li>~~
~~-</ul><h5>Supply</h5><ul><li>splenic flexure of large bowel to the upper two thirds of the <a href="/articles/rectum">rectum</a>~~
~~-</li></ul><h5>Relations</h5><ul>~~
~~-<li>~~
~~-<strong>anterior</strong>: third part of the <a href="/articles/duodenum">duodenum</a>~~
~~-</li>~~
~~-<li>~~
-<strong>posterior</strong>: <a href="/articles/abdominal-aorta-1">abdominal aorta</a>, left <a href="/articles/psoas-major-muscle-1">psoas</a>, sympathetic trunk, left <a href="/articles/common-iliac-artery">common iliac artery</a>, hypogastric nerve</li>
~~-<li>~~
~~-<strong>lateral (left)</strong>: <a href="/articles/inferior-mesenteric-vein">inferior mesenteric vein</a>~~
~~-</li>~~
-</ul><p>The <a title="inferior mesenteric plexus" href="/articles/inferior-mesenteric-plexus">inferior mesenteric plexus</a> (<a title="autonomic plexus" href="/articles/autonomic-ganglia-and-plexuses">autonomic plexus</a>) lies at the origin of the IMA.</p><p>The <a href="/articles/left-colic-artery">left colic</a> and <a href="/articles/sigmoid-arteries">sigmoid</a> branches of the IMA cross anterior to the <a href="/articles/ureter">ureter</a>. </p><h4>Variant anatomy</h4><ul>
~~-<li>doubled IMA</li>~~
~~-<li>absent IMA</li>~~
~~-<li>common trunks (e.g. left colic and rectosigmoid, rectal and colosigmoid)</li>~~
~~-<li>absent left colic branch</li>~~
~~-<li>~~
~~-<a href="/articles/arc-of-riolan">Arc of Riolan</a> (SMA/IMA connection)</li>~~
+<p>The <strong>inferior mesenteric artery (IMA)</strong> is one of the three non-paired major <a href="/articles/viscera">splanchnic arteries</a>, in the <a href="/articles/abdominal-cavity">abdominal cavity</a>, arising from the <a href="/articles/abdominal-aorta-1">abdominal aorta</a> and supplying the hindgut. It is the smallest of the three anterior visceral branches of the abdominal aorta.</p><h4>Gross anatomy</h4><h5>Location</h5><p>Located within the mesentery of the hindgut, passing to the left of the midline.</p><h5>Origin</h5><p>Unpaired vessel from the anterior aspect of the <a href="/articles/abdominal-aorta-1">abdominal aorta</a> at the L3 level, at the lower edge of the third part of duodenum <sup>5</sup>.</p><h5>Course</h5><p>The IMA runs obliquely downwards towards the pelvic brim, initially anterior and then to the left of the aorta. After giving off the left colic and sigmoid arteries, it crosses the origin of the left common iliac artery at the sacroiliac joint medial to the ureter, with the inferior mesenteric vein lying between the two. Within the pelvis, it continues along the pelvic wall as the superior rectal artery in the root of the sigmoid mesocolon.</p><h5>Branches</h5><ul>
+<li><p><a href="/articles/left-colic-artery">left colic artery</a></p></li>
+<li><p>two to four <a href="/articles/sigmoid-arteries">sigmoid arteries</a></p></li>
+<li><p><a href="/articles/superior-rectal-artery">superior rectal artery</a> (terminal branch)</p></li>
+</ul><h5>Supply</h5><ul><li><p>splenic flexure of large bowel to the upper two thirds of the <a href="/articles/rectum">rectum</a></p></li></ul><h5>Relations</h5><ul>
+<li><p><strong>anterior</strong>: third part of the <a href="/articles/duodenum">duodenum</a></p></li>
+<li><p><strong>posterior</strong>: <a href="/articles/abdominal-aorta-1">abdominal aorta</a>, left <a href="/articles/psoas-major-muscle-1">psoas</a>, sympathetic trunk, left <a href="/articles/common-iliac-artery">common iliac artery</a>, hypogastric nerve</p></li>
+<li><p><strong>lateral (left)</strong>: <a href="/articles/inferior-mesenteric-vein">inferior mesenteric vein</a></p></li>
+</ul><p>The <a href="/articles/inferior-mesenteric-plexus" title="inferior mesenteric plexus">inferior mesenteric plexus</a> (<a href="/articles/autonomic-ganglia-and-plexuses" title="autonomic plexus">autonomic plexus</a>) lies at the origin of the IMA.</p><p>The <a href="/articles/left-colic-artery">left colic</a> and <a href="/articles/sigmoid-arteries">sigmoid</a> branches of the IMA cross anterior to the <a href="/articles/ureter">ureter</a>. </p><h4>Variant anatomy</h4><ul>
+<li><p>doubled IMA</p></li>
+<li><p>absent IMA</p></li>
+<li><p>common trunks (e.g. left colic and rectosigmoid, rectal and colosigmoid)</p></li>
+<li><p>absent left colic branch</p></li>
+<li><p><a href="/articles/arc-of-riolan">Arc of Riolan</a> (SMA/IMA connection)</p></li>

References changed:

3. Bergman RA, Afifi AK, Miyauchi R. Anatomy Atlases – An Anatomy digital library - Curated by Roland A, Bergman. <a href="http://www.anatomyatlases.org/AnatomicVariants/Cardiovascular/Text/Arteries/InferiorMesenteric.shtml">Anatomy Atlases</a>
5. Stephanie Ryan, Michelle McNicholas, Stephen J. Eustace. Anatomy for Diagnostic Imaging. (2011) ISBN: 9780702029714 - <a href="http://books.google.com/books?vid=ISBN9780702029714">Google Books</a>
3. Bergman R, Afifi A, Miyauchi R. Anatomy Atlases – Abdominal Aorta. Cited Mar 2017. http://www.anatomyatlases.org/AnatomicVariants/Cardiovascular/Text/Arteries/InferiorMesenteric.shtml

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