Large Intestine Anatomy: Regions and Key Landmarks

Regions:

- Cecum:

- Initial portion of the large intestine.

- Located in the right iliac fossa.

- Ascending colon:

- Extends from cecum to hepatic flexure.

- Located on the right side of the abdomen.

- Hepatic flexure (right colic flexure):

- Located inferior to the liver.

- Where ascending colon turns to become transverse colon.

- Transverse colon:

- Extends from hepatic flexure to splenic flexure.

- Located horizontally across the abdomen.

- Splenic flexure (left colic flexure):

- Located inferior to the spleen.

- Where transverse colon turns to become descending colon.

- Descending colon:

- Extends from splenic flexure to pelvic brim.

- Located on the left side of the abdomen.

- Sigmoid colon:

- S-shaped portion of the colon.

- Located in the pelvis.

- Rectum:

- Terminal portion of the large intestine.

- Extends from sigmoid colon to the anus.

Anatomical landmarks:

- Ileocecal valve:

- Sphincter muscle that controls the passage of contents from ileum into cecum.

- Located at the junction of ileum and cecum.

- Appendices epiploicae:

- Small, fatty appendages hanging from the colon.

- Most prominent in the sigmoid colon.

- Taenia coli:

- Three muscular bands that run longitudinally along the colon.

- Tenia libera, tenia mesocolica, and tenia omentalis.

- Haustra:

- Outpouchings between the teniae coli.

- Plicae semilunares:

- Crescent-shaped folds of mucosa within the colon.

- Epiploic foramen (foramen of Winslow):

- Opening behind the lesser omentum that connects the lesser sac to the greater sac of the peritoneal cavity.