Anatomy - Right hemicolectomy

The colon encircles the inner abdominal wall and runs below the liver and stomach, surrounding the loops of the small intestine. The position of the colon is intra- or secondarily retroperitoneal. Its primary function is the thickening of the chyme by absorbing water. The total length of the colon is on average 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 following sections:

• Cecum with the appendix
• Ascending colon
• Transverse colon
• Descending colon
• Sigmoid colon

• 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
• Fat appendages from the tela subserosa in the area of the free taeniae are referred to as appendices epiploicae.
• Plicae semilunares are indentations of all wall layers intraluminally, whereas haustra are the outward bulges in between.

For right hemicolectomy, the following intestinal segments are relevant from oral to aboral:

• Right flexure and right lateral hemicolon
• Ascending colon
• Cecum with vermiform appendix

• Definition: blind initial part of the ascending colon, corresponding to a bulge of the same; lat.: caecus = blind
• Length 5-7 cm
• Synonyms: cecum, blind gut
• Location: intraperitoneal or also secondarily retroperitoneal, below the ileocecal valve, the Valva Bauhini
• Identification: by the taeniae and the vermiform appendix
• Vermiform appendix: intraperitoneal, in the area of the converging taeniae at the cecal pole, length: 6-20 cm, on average 8 cm, at the origin of the appendix the 3 taeniae unite

• Definition: Large intestine section between the ileocecal valve, the entry of the small intestine (ileum), and the right colic flexure
• Synonyms: ascending colon, or simply Ascendens
• Location: [secondarily] retroperitoneal, extends from the right lower abdomen to the right flexure – peritoneal fixation to the posterior abdominal wall by the so-called Toldt's fascia
• Length: 12-20 cm
• Identification: by the longitudinal muscle fiber bundles – the taeniae, which retain their positional names from the transverse colon; the transverse diameter is significantly larger than that of the descending colon!