- Sigmoid colon
Sigmoid colon Front of abdomen, showing surface markings for liver, stomach, and great intestine. Latin colon sigmoideum Gray's subject #249 1182 Artery sigmoid arteries Nerve superior mesenteric ganglia, sacral nerve  Precursor hindgut
The sigmoid colon (pelvic colon) is the part of the large intestine that is closest to the rectum and anus. It forms a loop that averages about 40 cm. in length, and normally lies within the pelvis, but on account of its freedom of movement it is liable to be displaced into the abdominal cavity.
It begins at the superior aperture of the lesser pelvis, where it is continuous with the iliac colon, and passes transversely across the front of the sacrum to the right side of the pelvis. (The name sigmoid aptly means S-shaped.)
It is completely surrounded by peritoneum (and thus is not retroperitoneal), which forms a mesentery (sigmoid mesocolon), which diminishes in length from the center toward the ends of the loop, where it disappears, so that the loop is fixed at its junctions with the iliac colon and rectum, but enjoys a considerable range of movement in its central portion.
Behind the sigmoid colon are the external iliac vessels, the left Piriformis, and left sacral plexus of nerves.
- Search sigmoid+colon at eMedicine Dictionary
- SUNY Figs 37:06-07 - "The large intestine."
- Superior & Inferior Mesenteric Artery at The Anatomy Lesson by Wesley Norman (Georgetown University)
Anatomy of torso, digestive system: Gastrointestinal tract, excluding mouth (TA A05.3–7, TH H3.04.02-04, GA 11.1141) Upper GIGoblet cell Lower GILayersno substructuresLayersTransverse folds of rectum • Rectal ampulla
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