Diagnostic Ultrasound - Abdomen and Pelvis

Bowel
Anatomy: Abdomen
LARGE BOWEL
Abdominal wall musculature
Long-axis view of collapsed descending
colon
Abdominal wall
Muscularis propria layer
Compressed lumen
Submucosal layer
Muscularis mucosa
Compressed lumen
Muscularis propria layer
Psoas muscle
Loops of pelvic loops of small bowel
Muscularis propria layer
Sigmoid colon
Iliacus muscle in pelvic wall
(Top) Left sagittal ultrasound shows the normal descending colon in a collapsed state and compressed by the ultrasound probe. Note
the gut signature. This is an alternative appearance to the descending colon when it is collapsed and empty. (Middle) High-resolution
left sagittal ultrasound obtained with a higher frequency linear probe from the same patient shows the collapsed descending colon
with gut signature. The hypoechoic outer layer represents the muscularis propria layer. (Bottom) Transvaginal ultrasound shows the
sigmoid colon and pelvic loops of small bowel. Note the hypertrophied outer muscularis propria layer of the sigmoid colon, seen in
patients with irritable bowel syndrome and early diverticular disease.
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