- The colon surrounds the loops of the small intestine along the inner abdominal wall and beneath the liver and stomach. The position of the colon is intra- or secondarily retroperitoneal. Its primary function is the thickening of the chyme through the absorption of water. The total length of the colon averages 120-150 cm. The colon begins at the ileocecal valve and ends at the rectosigmoid junction, where it transitions into the rectum.
- The colon is divided into the sections:
- Cecum with the appendix
- Ascending colon
- Transverse colon
- Descending colon
- Sigmoid colon
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Overview
![Overview]()
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Macroscopy
![Macroscopy]()
- The longitudinal muscle layers of the colon form three band-like muscle strips that are visible from the outside and are referred to as taeniae. They are distinguished as follows:
- Taenia mesocolica: located towards the mesentery
- Taenia libera: free on the surface, facing the abdominal wall
- Taenia omentalis: connected with the greater omentum
- Appendices epiploicae are fatty appendages from the tela subserosa in the area of the free taeniae.
- Plicae semilunares are indentations of all wall layers intraluminally, whereas haustra are the outward bulges in between.
- For left hemicolectomy, the following intestinal segments are relevant from oral to aboral:
- distal transverse colon
- left flexure
- descending colon
- sigmoid colon
- upper rectum
- The longitudinal muscle layers of the colon form three band-like muscle strips that are visible from the outside and are referred to as taeniae. They are distinguished as follows:
-
Transverse, Descending, and Sigmoid Colon
![Transverse, Descending, and Sigmoid Colon]()
- Transverse Colon
- Synonyms: transverse colon or simply Transversum.
- Location: intraperitoneal; mobile fixation through its own mesentery – transverse mesocolon, runs transversely ascending through the abdominal cavity from the right to the left flexure
- Length: 30-45 cm
- Identification: by the three taeniae and the greater omentum attached to the taenia omentalis
- The left flexure is always higher than the right flexure due to its fixation by the phrenicocolic ligament
- Descending Colon:
- Location: secondarily retroperitoneal
- Peritoneal suspension: fused with the posterior abdominal wall
- Course: from the left flexure (here: phrenicocolic ligament with fixation to the spleen) to the iliac fossa, connects to the transverse colon and transitions into the sigmoid colon
- Length: 20-30 cm
- Sigmoid Colon
- Location: intraperitoneal
- Peritoneal suspension: sigmoid mesocolon
- Course: from the iliac fossa as a loop (S-shaped) to the level of the 2nd-3rd sacral vertebrae, connects to the descending colon and transitions into the rectum
- Length: variable (elongated sigmoid), generally: about 35 cm
- Transverse Colon
Vascular Supply, Lymphatic Drainage, and Nerves
Arterial supply of the left hemicolon, sigmoid colon up to the upper rectum by the inferior mesente
Arterial supply of the left hemicolon, sigmoid colon up to the upper rectum by the inferior mesente
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