Topics

Topic

design image
Anterior horn of lateral meniscus

The anterior horn of the lateral meniscus is the front-most portion of the C-shaped lateral meniscus of the knee joint. The lateral meniscus is more circular and mobile than the medial meniscus, and its anterior horn plays a critical role in stabilizing the femur-tibia articulation, distributing load, and maintaining knee biomechanics.

The anterior horn attaches firmly to the tibial plateau anterior to the intercondylar eminence, close to the anterior cruciate ligament (ACL) attachment. Due to its location, the anterior horn of the lateral meniscus is vulnerable to injury in association with ACL tears and rotational knee trauma.

Synonyms

  • Anterior segment of lateral meniscus

Relations

  • Anteriorly: Joint capsule and anterior fat pad

  • Posteriorly: Body of the lateral meniscus

  • Medially: Anterior cruciate ligament (ACL) attachment at tibial spine

  • Laterally: Lateral tibial plateau and lateral femoral condyle cartilage

  • Superiorly: Femoral condyle articular cartilage

  • Inferiorly: Tibial plateau articular surface

Function

  • Distributes load across the lateral knee compartment

  • Contributes to shock absorption during weight-bearing

  • Stabilizes the femoral condyle during flexion and extension

  • Assists in joint lubrication and congruency

  • Provides proprioceptive input for knee mechanics

Clinical Significance

  • Tears: Common site of meniscal injury, particularly with ACL tears or twisting trauma

  • Meniscal cysts: May form adjacent to tears

  • Iatrogenic injury: At risk during arthroscopic procedures

  • Degenerative changes: May show fraying or horizontal cleavage tears in older patients

  • Arthrogram imaging: Used for subtle tears or postoperative assessment

MRI Appearance

T1-weighted images:

  • Meniscus, including anterior horn, shows low signal intensity (dark)

  • Tears or cysts may appear as linear or focal bright signal extending to articular surface

T2-weighted images:

  • Normal anterior horn shows uniform low signal

  • Tears appear as linear high signal reaching the surface

  • Mucoid degeneration shows increased intrasubstance signal without surface extension

STIR (Short Tau Inversion Recovery):

  • Meniscus remains dark

  • Tears and fluid-related pathology appear bright, increasing conspicuity

Proton Density Fat-Saturated (PD FS):

  • Normal horn remains low signal

  • Tears: bright linear signal extending to articular surface

  • Useful for detecting subtle tears near tibial attachment

T1 Fat-Sat Post-Contrast:

  • Normal horn does not enhance

  • Postoperative scar or synovitis may show enhancement adjacent to anterior horn

3D T2 SPACE :

  • Provides clear delineation of meniscal borders

  • Anterior horn appears dark band, sharply contrasted against bright joint fluid

MRI Arthrogram Appearance

  • Contrast enters tear lines of the anterior horn, appearing as bright extension of gadolinium into meniscus substance

  • Distinguishes true tears from intrasubstance degeneration

  • Postoperative: differentiates recurrent tear (contrast extends into horn) from scar tissue (enhances on post-contrast but no gadolinium entry)

CT Appearance

Non-Contrast CT:

  • Meniscus is poorly visualized

  • Large calcifications, ossified meniscal fragments, or displaced bucket-handle tears may be seen as soft tissue density

CT Arthrogram:

  • Normal anterior horn: well-defined triangular low-density structure outlined by intra-articular contrast

  • Tear: contrast fills clefts or linear defects within anterior horn

  • Useful in patients who cannot undergo MRI

MRI images

Anterior horn of lateral meniscus axial cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

MRI images

Anterior horn of lateral meniscus coronal cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

MRI images

Anterior horn of lateral meniscus sagittal cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000