Caecum

The caecum is the first part of the large bowel and lies in the right lower quadrant of the abdomen. 

Blind-ending sac of bowel that lies below the ileocaecal valve, above which the large intestine continues as the ascending colon. The caecum measures 6 cm in length and can have a maximum diameter of 9 cm before it is considered abnormally enlarged. The vermiform appendix typically arises from the posteromedial surface, 2 cm inferior to the ileocaecal valve 1.

The caecum is covered by peritoneum, except posteriorly where it has a layer of loose connective tissue and it has a variable mesentery 1

The superior margin of the caecum is defined by the ileocaecal ostium. Upper and lower flaps consisting of smooth muscle protrude into the lumen around the ostium forming the ileocaecal valve 2. Its competence is often shown by the lack of contrast reflux into the terminal ileum on contrast enema studies.

The lymphatic network runs parallel to the arterial supply, to paracolic lymph nodes, which drain to the superior mesenteric group.

  • sympathetic supply via the superior mesenteric plexus
  • parasympathetic supply via fibers from the anterior and posterior vagal trunks
  • subhepatic caecum: failure of the caecum to migrate to its typical position during midgut rotation in embryogenesis 3
  • mobile caecum
    • right colonic mesentery fails to fuse to the lateral peritoneum 4
    • occurs in ~15% of the population 4

Caecum is short for the Latin term intestinum caecum, which means blind gut.

Abdominal and pelvic anatomy
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Article information

rID: 22635
Section: Anatomy
Synonyms or Alternate Spellings:
  • Cecum

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Cases and figures

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    Normal caecum and...
    Figure 1: normal relationship
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    Figure 2
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    Case 1: subhepatic caecum
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    Case 2: mobile caecum identing the bladder
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