Ileocecal junction

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The ileocecal valve separates the terminal ileum from the cecum and functions to regulate flow between these two structures and prevent reflux from the cecum into the small intestine.

Gross anatomy

The ileocecal valve consists of two muscular layers of ileum, an upper and lower lip, that are covered by mucuosa and protrude into the lumen of the caecaum supported by mucosal folds called frenula. This forms the opening of the terminal ileum into the medial cecum and delineates the upper margin of the cecum from the ascending colon.

The morphology of the ileocecal valve has be described on endoscopy as :

  • labial-type: slit-like opening (most common)
  • papillary-type: dome-shaped
  • lipomatous: significant amount of fat demonstrated in the lips

Variant anatomy

  • lateral (~7.5%) or posterior opening (~5%)

Radiographic appearance

Fluroscopy
  • identified on barium enema as an oval or triangular-shaped filling defect with smooth or lobulated surfaces
CT
  • best viewed on supine imaging
  • mixed-density structure at the junction of the ileum and cecum with an average density of -25 HU (range -60 HU to +18 HU)

Related pathology