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Anterior rim of acetabulum

The anterior rim of the acetabulum is the anterior margin of the acetabular socket of the hip joint. It contributes to the containment and stability of the femoral head and serves as an attachment site for the acetabular labrum and capsular ligaments. It plays a key role in hip biomechanics and is an important landmark in orthopedic anatomy and hip imaging.

This region is particularly relevant in the evaluation of hip stability, femoroacetabular morphology, and labral relationships.

Synonyms

  • Anterior acetabular rim

  • Anterior acetabular margin

Location

  • Situated at the anterior border of the acetabulum

  • Forms part of the acetabular circumference

  • Located between the anterosuperior and anteroinferior acetabular quadrants

  • Faces anterolaterally toward the femoral head

  • Continuous with the superior and inferior acetabular rims

Anatomical components

  • Osseous margin of the acetabulum

  • Articular surface:

    • Covered by acetabular cartilage

  • Labral attachment:

    • Acetabular labrum is anchored to the rim

  • Capsular attachment:

    • Hip joint capsule blends with the rim and labrum

  • Adjacent landmarks:

    • Anterior inferior iliac spine (AIIS)

    • Iliopubic eminence

Relations

Anteriorly:

  • Iliopsoas muscle and tendon

  • Hip joint capsule

Posteriorly:

  • Acetabular fossa and posterior rim

Superiorly:

  • Acetabular roof (sourcil)

Inferiorly:

  • Acetabular notch and transverse acetabular ligament

Laterally:

  • Femoral head

Medially:

  • Pelvic cavity

X-ray appearance

Plain radiographs (AP pelvis and oblique views):

  • Anterior rim: Seen as part of the acetabular outline

  • Best appreciated on: False-profile and Dunn views

  • Contour: Smooth and continuous arc anterior to femoral head

  • Relationship: Helps define anterior acetabular coverage

CT appearance (Pre-contrast)

Non-contrast CT:

  • Anterior rim: Well-defined cortical margin of the acetabulum

  • Cortical bone: High-density smooth outline

  • Trabecular bone: Normal internal architecture

  • 3D understanding: Accurate depiction of rim contour and version

  • Labrum: Not directly visualized, inferred by rim location

MRI appearance

T1-weighted images:

  • Cortical bone: Low signal intensity

  • Marrow of acetabulum: High signal intensity

  • Anterior rim contour: Clearly delineated against adjacent soft tissues

T2-weighted images:

  • Cortical margins: Low signal

  • Joint fluid: High signal outlining the rim

  • Labrum: Low-to-intermediate signal triangular structure attached to the rim

STIR:

  • Fat suppression: Improves visualization of marrow and soft tissues

  • Rim margins: Well-defined

  • Labrum and capsule: Visualized against suppressed fat background

Proton density fat-saturated (PD FS):

  • Joint fluid: Bright high signal

  • Labrum: Low-signal triangular structure along the rim

  • Cartilage: Intermediate signal

  • Rim-cartilage-labrum interface: Well demonstrated

CT VRT 3D image

Anterior rim of acetabulum 3d

CT image

Anterior rim of acetabulum ct axial

MRI image

Anterior rim of acetabulum mri anatomy labelled image-img-00000-00000