Terminal ileum
Updates to Article Attributes
Theterminal ileum is the most distal segment of small bowel. It immediately immediately precedes the small bowel's connection with the colon through the ileocaecal valve. It is of particular interest since a number of infectious and inflammatory processes preferentially involve the segment.
- location: the most distal ileum, ~30 cm proximal to the ileocaecal valve
-
blood supply: branches of the ileocolic artery, including the
ilealileal branch of ileocolic artery and the recurrent ileal artery
Gross anatomy
Relations and/or Boundaries
Although the terminal ileum is more or less considered the 30 cm of ileum that precedes the ileocaecal valve and caecum, it can also be thought of as a functional definition; the portion of distal ileum that is more lymphatic lymphatic-rich than the rest of the ileum.
BloodArterial supply
The terminal ileum is supplied mainly by branches of theileocolic artery (which arises off the superior mesenteric artery)
- ileal branch of ileocolic artery
- recurrent ileal artery
Venous drainage
- accompany the respective arteries and drain into the superior mesenteric vein
Lymphatic supplydrainage
Lymphatic
-
lymphatic aggregates are more dense in this segment than elsewhere in the ileum
.
Radiographic features
Except in cases of intestinal malrotation, the terminal ileum is located in the right lower quadrant on imaging.
Fluoroscopy
Small bowel follow through (SBFT)
- circular folds are sparse in the terminal ileum and the mucosa can sometimes appear essentially featureless
Ultrasound
- normal ultrasound gut signature
- the terminal ileum can occasionally be mistaken for the appendix, but the terminal ileum is not blind-ending and usually is peristalsing
CT and MR MR enterography
- located in the right lower quadrant
- appears similar to other ileal loops unless inflamed
- circular folds are more sparse in this segment than in other segments of the ileum
Related pathology
In addition to more general disorders involving the small bowel, the lymphatic-rich terminal ileum is a common target of some infectious organism and some generalised inflammatory inflammatory processes
In addition, because of its location immediately preceding the colon, it can be involved with colonic processes as well
False-positive evaluation for inflammatory bowel disease in the terminal ileum on fluoroscopy may be due to underdistention orlymphoid nodular hyperplasia.
-<p>The <strong>terminal ileum</strong> is the most distal segment of <a href="/articles/small-bowel">small bowel</a>. It immediately precedes the small bowel's connection with the <a href="/articles/large-intestine-1">colon</a> through the <a href="/articles/ileocaecal-valve">ileocaecal valve</a>. It is of particular interest since a number of infectious and inflammatory processes preferentially involve the segment.</p><ul>- +<p>The <strong>terminal ileum</strong> is the most distal segment of <a href="/articles/small-bowel">small bowel</a>. It immediately precedes the small bowel's connection with the <a href="/articles/large-intestine-1">colon</a> through the <a href="/articles/ileocaecal-valve">ileocaecal valve</a>. It is of particular interest since a number of infectious and inflammatory processes preferentially involve the segment.</p><ul>
-<strong>blood supply</strong>: branches of the <a href="/articles/ileocolic-artery">ileocolic artery</a>, including the ileal branch of ileocolic artery and the recurrent ileal artery</li>-</ul><h4>Gross anatomy</h4><h5>Relations and/or Boundaries</h5><p>Although the terminal ileum is more or less considered the 30 cm of ileum that precedes the ileocaecal valve and caecum, it can also be thought of as a functional definition; the portion of distal ileum that is more lymphatic-rich than the rest of the ileum.</p><h4>Blood supply</h4><p>The terminal ileum is supplied mainly by branches of the <a href="/articles/ileocolic-artery">ileocolic artery</a> (which arises off the <a href="/articles/superior-mesenteric-artery">superior mesenteric artery</a>)</p><ul>- +<strong>blood supply</strong>: branches of the <a href="/articles/ileocolic-artery">ileocolic artery</a>, including the ileal branch of ileocolic artery and the recurrent ileal artery</li>
- +</ul><h4>Gross anatomy</h4><h5>Relations and/or Boundaries</h5><p>Although the terminal ileum is more or less considered the 30 cm of ileum that precedes the ileocaecal valve and caecum, it can also be thought of as a functional definition; the portion of distal ileum that is more lymphatic-rich than the rest of the ileum.</p><h4>Arterial supply</h4><p>The terminal ileum is supplied mainly by branches of the <a href="/articles/ileocolic-artery">ileocolic artery</a> (which arises off the <a href="/articles/superior-mesenteric-artery">superior mesenteric artery</a>)</p><ul>
-</ul><h4>Lymphatic supply</h4><p>Lymphatic aggregates are more dense in this segment than elsewhere in the ileum.</p><h4>Radiographic features</h4><p>Except in cases of <a href="/articles/intestinal-malrotation">intestinal malrotation</a>, the terminal ileum is located in the right lower quadrant on imaging.</p><h5>Fluoroscopy</h5><p><strong>Small bowel follow through (SBFT)</strong></p><ul><li>circular folds are sparse in the terminal ileum and the mucosa can sometimes appear essentially featureless</li></ul><h5>Ultrasound</h5><ul>- +</ul><h4>Venous drainage</h4><ul><li>accompany the respective arteries and drain into the <a title="Superior mesenteric vein" href="/articles/superior-mesenteric-vein">superior mesenteric vein</a>
- +</li></ul><h4>Lymphatic drainage</h4><ul><li>lymphatic aggregates are more dense in this segment than elsewhere in the ileum</li></ul><h4>Radiographic features</h4><p>Except in cases of <a href="/articles/intestinal-malrotation">intestinal malrotation</a>, the terminal ileum is located in the right lower quadrant on imaging.</p><h5>Fluoroscopy</h5><p><strong>Small bowel follow through (SBFT)</strong></p><ul><li>circular folds are sparse in the terminal ileum and the mucosa can sometimes appear essentially featureless</li></ul><h5>Ultrasound</h5><ul>
-<li>the terminal ileum can occasionally be mistaken for the <a href="/articles/appendix">appendix</a>, but the terminal ileum is not blind-ending</li>-</ul><h5>CT and MR enterography</h5><ul>- +<li>the terminal ileum can occasionally be mistaken for the <a href="/articles/appendix-1">appendix</a>, but the terminal ileum is not blind-ending and usually is peristalsing</li>
- +</ul><h5>CT and MR enterography</h5><ul>
-</ul><h4>Related pathology</h4><p>In addition to more general disorders involving the small bowel, the lymphatic-rich terminal ileum is a common target of some infectious organism and some generalised inflammatory processes</p><ul><li><a href="/articles/terminal-ileitis-differential">terminal ileitis (differential)</a></li></ul><p>In addition, because of its location immediately preceding the colon, it can be involved with colonic processes as well</p><ul>- +</ul><h4>Related pathology</h4><p>In addition to more general disorders involving the small bowel, the lymphatic-rich terminal ileum is a common target of some infectious organism and some generalised inflammatory processes</p><ul><li><a href="/articles/terminal-ileitis-differential">terminal ileitis (differential)</a></li></ul><p>In addition, because of its location immediately preceding the colon, it can be involved with colonic processes as well</p><ul>
-</ul><p>False-positive evaluation for inflammatory bowel disease in the terminal ileum on fluoroscopy may be due to underdistention or <a href="/articles/lymphoid-nodular-hyperplasia">lymphoid nodular hyperplasia</a>.</p>- +</ul><p>False-positive evaluation for inflammatory bowel disease in the terminal ileum on fluoroscopy may be due to underdistention or <a href="/articles/lymphoid-nodular-hyperplasia">lymphoid nodular hyperplasia</a>.</p>