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Crista galli

The crista galli is a thin, vertical, midline bony projection extending superiorly from the cribriform plate of the ethmoid bone. It forms a central anchoring point for the falx cerebri and contributes to the separation of the two olfactory bulbs within the anterior cranial fossa. Inferiorly, it projects down toward the nasal cavity, forming part of the nasal septum via its articulation with the perpendicular plate of the ethmoid.

It is a crucial landmark in endoscopic sinus surgery, anterior skull base surgery, and in assessing fractures involving the cribriform plate. The crista galli may contain a pneumatized cavity (pneumatized crista galli), which is clinically significant in sinonasal disease and surgical approaches.

Synonyms

  • Ethmoidal crest

  • Midline ethmoid projection

Location and Structure

  • Position: Midline structure of the anterior cranial fossa, projecting upward from the cribriform plate.

  • Composition: Thin cortical bone with potential internal pneumatization.

  • Articulations:

    • Superiorly: Anchors falx cerebri

    • Inferiorly: Continuation into perpendicular plate of ethmoid

    • Laterally: Flanked by olfactory grooves housing olfactory bulbs

Relations

  • Superiorly: Falx cerebri attachment

  • Inferiorly: Cribriform plate and nasal cavity roof

  • Anteriorly: Frontal sinus region (variable pneumatization contact)

  • Posteriorly: Frontal recess and ethmoid air cells

  • Laterally: Olfactory bulbs and tracts on either side of cribriform plate

Function

  • Serves as the anchor point for the falx cerebri

  • Contributes to midline structural stability of the anterior cranial fossa

  • Helps separate left and right olfactory bulbs

  • Provides an anatomical landmark for endoscopic sinus and skull base surgery

 

MRI Appearance

T1-weighted images

  • Cortical bone: Very low signal (black)

  • Marrow-containing variants:

    • Bright high signal due to fatty marrow

  • Pneumatized variants:

    • Air: very low signal

    • Mucosal lining: intermediate signal

  • Adjacent dura (falx): Thin intermediate signal

T2-weighted images

  • Cortex: Low signal

  • Marrow (if present):

    • Hyperintense to intermediate depending on fat content

  • Pneumatized crista galli:

    • Air cavity: very low signal

    • Mucosa: intermediate-to-bright

  • CSF around olfactory grooves: Bright

STIR

  • Cortical bone: Dark

  • Bone marrow (variant):

    • Intermediate-to-dark signal (fat suppressed)

  • Mucosal lining in pneumatized variants:

    • Bright due to fluid-sensitive contrast

  • Fat suppression: Enhances visibility of bony margins

3D T2 (SPACE / CISS)

  • Crista galli cortex: Sharp, low-signal outline

  • Marrow (variant):

    • Intermediate-to-bright depending on sequence weighting

  • Pneumatized cavity:

    • Air: very low signal

    • Mucosa: smooth bright lining

  • Excellent for defining relationship to cribriform plate & olfactory grooves

T1 Fat-Sat Post-Contrast

  • Bone: No enhancement

  • Marrow (variant):

    • Mild homogeneous enhancement typical of normal marrow

  • Dural attachment (falx cerebri):

    • Linear thin enhancement

  • Pneumatized mucosa:

    • Uniform mucosal enhancement (normal)

CT Appearance

Non-Contrast CT:

  • Crista galli appears as a dense, midline bony ridge projecting upward from the cribriform plate

  • Excellent visualization of cortical margins

  • Pneumatized variants appear as air-filled or mucosal-lined cavities

  • Symmetry, size, and bony thickness easily evaluated

MRI image

Crista galli MRI axial image-img-00000-00000

CT image

Crista galli CT AXIAL IMAGE

CT image

Crista galli ct coronal

CT image

Crista galli

MRI image

MRI Crista galli anatomy image -img-00000-00000