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Cecum

The cecum is the initial intraperitoneal segment of the large intestine, located in the right iliac fossa. It lies below the ileocecal junction, where the terminal ileum enters medially through the ileocecal valve. The appendix typically arises from its posteromedial aspect at the convergence of the three taeniae coli.

The cecum is a blind-ended pouch, approximately 6–9 cm long, and serves as a reservoir for chyme entering from the small intestine. Its walls contain lymphoid tissue and are thinner than those of the colon. It is completely covered by peritoneum, making it highly mobile.

Anatomically, the cecum is related anteriorly to the anterior abdominal wall and greater omentum, posteriorly to the iliacus and psoas major muscles, and medially to the terminal ileum and mesentery.

The cecum plays an important role in fluid absorption, microbial fermentation, and mixing of intestinal contents. It is clinically significant in appendicitis, volvulus, cecal cancer, and inflammatory bowel disease.

Synonyms

  • Caecum

  • Initial segment of large intestine

  • Ileocecal pouch

Function

  • Receives chyme from the terminal ileum via the ileocecal valve

  • Serves as a reservoir for intestinal contents

  • Aids in water and electrolyte absorption

  • Supports microbial fermentation

  • Provides anatomical attachment site for the appendix

Nerve Supply

  • Parasympathetic: Vagus nerve (via superior mesenteric plexus)

  • Sympathetic: Lower thoracic splanchnic nerves (T10–T12) via superior mesenteric plexus

  • Provides autonomic regulation of motility and secretion

Arterial Supply

  • Anterior cecal artery (branch of ileocolic artery from SMA)

  • Posterior cecal artery (branch of ileocolic artery from SMA)

Venous Drainage

  • Cecal veins → ileocolic vein → superior mesenteric vein (SMV) → portal vein

MRI Appearance

T1-weighted images:

  • Cecal wall appears intermediate signal with clear delineation from hyperintense surrounding fat

  • Lumen shows variable signal depending on chyme/gas

T2-weighted images:

  • Cecal lumen fluid appears bright hyperintense

  • Wall shows intermediate-to-low signal intensity

  • Thickened hyperintense wall suggests edema, colitis, or tumor

STIR:

  • Suppresses fat, making cecal wall and inflammatory changes stand out

  • Highlights pericecal edema, abscesses, or inflammatory bowel disease activity

T1 Fat-Saturated (Pre-contrast):

  • Cecal wall appears intermediate signal against suppressed fat background

  • Useful for wall-to-fat contrast differentiation

T1 Fat-Saturated Post-Contrast (Gadolinium):

  • Cecal wall enhances uniformly in normal state

  • Heterogeneous or irregular enhancement suggests colitis, ischemia, or neoplasm

  • Identifies abscesses, fistulae, or tumor infiltration

MRI Non-Contrast 3D Imaging:

  • Provides multiplanar visualization of the cecum and ileocecal junction

  • Useful in surgical mapping and congenital anomaly evaluation

CT Appearance

CT Pre-Contrast:

  • Cecum visible as a thin-walled, air- or fluid-filled pouch in right iliac fossa

  • Detects calcifications, intraluminal foreign bodies, or obstruction

CT Post-Contrast:

  • Normal cecal wall enhances mildly and uniformly

  • Wall thickening (>3 mm), pericecal fat stranding, or heterogeneous enhancement indicates colitis, ischemia, or carcinoma

  • Useful in diagnosing appendicitis, cecal tumors, and volvulus

CT images

Cecum MRI axial image

CT images

Cecum MRI coronal image 1

CT images

Cecum MRI coronal image

MRI image

Cecum anatomy MRI sag anatomy image -img-00000-00000