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Anterior horn of medial meniscus

The anterior horn of the medial meniscus is the front portion of the C-shaped medial meniscus, a fibrocartilaginous structure in the knee joint. It attaches to the tibial plateau anteriorly and helps form a crucial load-bearing and stabilizing cushion between the femur and tibia.

This structure plays a significant role in shock absorption, joint stability, load distribution, and proprioception. Its integrity is essential for normal biomechanics of the knee, and anterior horn tears are less common than posterior horn tears but may occur in trauma, sports injuries, or degenerative processes.

Synonyms

  • Anterior segment of medial meniscus

  • Front horn of medial meniscus

  • Anterior medial meniscal attachment

Location and Relations

  • Location: Anterior horn is situated at the anterior margin of the medial tibial plateau, anterior to the intercondylar eminence.

  • Relations:

    • Anteriorly: Joint capsule and anterior intermeniscal ligament (sometimes present, connecting to lateral meniscus)

    • Posteriorly: Body of the medial meniscus

    • Medially: Medial joint capsule and medial collateral ligament (MCL) complex

    • Laterally: Anterior cruciate ligament (ACL) attaches nearby in the intercondylar area

    • Superiorly: Contacts the medial femoral condyle cartilage

    • Inferiorly: Anchored to tibial plateau by anterior root attachment

Function

  • Acts as a cushion between tibial plateau and femoral condyle during flexion/extension

  • Contributes to shock absorption and even distribution of load across the knee joint

  • Provides anterior-posterior stability in coordination with cruciate ligaments

  • Assists in knee proprioception

Clinical Significance

  • Tears in the anterior horn may result from acute trauma, sports injuries, or chronic degeneration

  • Associated with anterior knee pain, locking, and instability

  • Important in arthroscopy and imaging for diagnosis and treatment planning

  • Tears can occur in isolation or with ACL/MCL injuries

  • Degenerative changes common in osteoarthritis may involve anterior horn

MRI Appearance

T1-weighted images:

  • Meniscus appears as homogeneous low signal (dark) fibrocartilage

  • Tears may appear as linear or irregular hyperintense lines extending to articular surface

T2-weighted images:

  • Normal meniscus: uniformly dark (low signal)

  • Tear: bright hyperintense line or cleft reaching the articular surface

  • Degeneration: diffuse increased signal not extending to surface

STIR (Short Tau Inversion Recovery):

  • Normal meniscus: dark structure

  • Tears and inflammation: hyperintense signal

Proton Density Fat-Saturated (PD FS):

  • Normal: dark, well-defined wedge-shaped structure

  • Tear: bright signal abnormality extending to articular surface

T1 Fat-Sat Post-Contrast:

  • Normal: meniscus does not enhance

  • Pathology: peripheral enhancement in vascularized tears or associated synovitis

3D T2 SPACE / CISS:

  • Anterior horn appears as well-defined low signal fibrocartilage

  • Provides high-resolution multiplanar evaluation for subtle tears and root pathology

MRI Arthrogram

  • Normal anterior horn fills defect-free with surrounding low signal meniscus

  • Tear: contrast extends into the meniscus substance or cleft, delineating partial or complete tear

  • Root avulsion or detachment visualized by contrast insinuation into root footprint

CT Appearance

Non-Contrast CT:

  • Meniscus poorly visualized; appears as soft tissue density in intercondylar and medial tibial plateau region

  • Calcification may be seen in degenerative disease

CT Arthrogram:

  • Contrast outlines anterior horn contour

  • Tear or detachment: contrast penetrates into meniscal substance

  • Excellent for patients who cannot undergo MRI

MRI image

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

MRI image

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

MRI image

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