Caecum

Dr Owen Kang and Dr Henry Knipe et al.

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 appendix typically arises from the posteromedial surface, 2 cm inferior to the ileocaecal valve 1.

The caecum is covered in 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 (or lack of) is often shown by  contrast reflux into the terminal ileum of contrast on contrast enema studies.

Relations

Lymph travels with the arterial supply to paracolic lymph nodes, which drain to the superior mesenteric group.

  • subhepatic caecum: failure of the caecum to migrate to its typical position during midgut rotation in embryogenesis 3
  • mobile caecum
    • right colonic mesentery fails the fuse to the lateral peritoneum 4
    • occurs in ~15% of the population 4
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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