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Left colic flexure (splenic flexure)

The left colic flexure, also known as the splenic flexure, is the sharp bend of the colon between the transverse colon and the descending colon. It lies in the left upper quadrant of the abdomen, just inferior to the spleen. This flexure is more acute and fixed compared to the hepatic flexure, because it is tethered by the phrenicocolic ligament.

It is clinically important because it is a common site for ischemia (“splenic flexure syndrome”) due to its location at a vascular watershed zone between the superior and inferior mesenteric arterial supplies.

Synonyms

  • Splenic flexure

  • Left colic flexure

  • Left upper colonic bend

Location and Relations

  • Anteriorly: Stomach (greater curvature) and left costal margin

  • Posteriorly: Left kidney and diaphragm

  • Medially: Pancreatic tail

  • Superiorly: Spleen and diaphragm

  • Inferiorly: Jejunum and transverse mesocolon

Function

  • Marks the transition between the transverse and descending colon

  • Participates in colonic mixing, propulsion, and water absorption

  • Represents an important vascular watershed zone

Clinical Significance

  • Prone to ischemia (splenic flexure syndrome) due to dual vascular supply (SMA/IMA watershed)

  • Site of colonic obstruction or volvulus

  • Important landmark during left hemicolectomy

  • Tumors at this site may present late due to relative inaccessibility

MRI Appearance

T1-weighted GRE (Gradient Echo):

  • Colonic wall: thin low signal

  • Lumen air: signal void (black)

  • Lumen fat (stool with fat): bright signal

  • Masses or abnormal thickening: low-to-intermediate signal

T2-weighted HASTE (Half-Fourier Single-shot Turbo Spin Echo):

  • Colonic lumen fluid: bright hyperintense

  • Lumen air: dark signal void (black)

  • Normal wall: thin dark hypointense line

  • Pathologic wall (tumor, colitis, edema): intermediate-to-bright signal

CT Appearance

Non-Contrast CT:

  • Colonic wall: thin soft tissue density

  • Lumen air: black, very low attenuation

  • Lumen fluid: low attenuation (10–20 HU)

  • Fecal material: mixed attenuation with mottled air

  • Pathology: wall thickening, pericolic fat stranding, masses

Post-Contrast CT:

  • Normal wall: mild, uniform enhancement

  • Inflammation: concentric thickening with mucosal hyperenhancement

  • Tumors: irregular, enhancing soft tissue mass, may narrow lumen

  • Complications: abscess (rim-enhancing), perforation (free air)

CT Colonoscopy (Virtual Colonoscopy):

  • Flexure: appears as an acute sharp bend between transverse and descending colon

  • Lumen air: distended black lumen provides negative contrast

  • Normal wall: thin, smooth contour with sharp fold transitions

  • Tumors/polyps: intraluminal enhancing or non-enhancing masses projecting into air lumen

  • Obstruction: abrupt narrowing, proximal dilatation, absence of distal air

CT image

Left colic flexure (splenic flexure) ct coronal anatomy image-img-00000-00000

CT image

Left colic flexure (splenic flexure) ct sagittal anatomy image-img-00000-00000

MRI image

Left colic flexure (splenic flexure) mri sagittal anatomy image-img-00000-00000

MRI image

Left colic flexure (splenic flexure) MRI coronal anatomy image-img-00000-00000