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Body of lateral meniscus

The body of the lateral meniscus is the central portion of the O-shaped lateral meniscus, positioned between the anterior and posterior horns. Compared with the medial meniscus, it is smaller, more circular, and more mobile due to its looser capsular attachment and separation from the lateral collateral ligament by the popliteus tendon.

It plays a vital role in load distribution, shock absorption, and joint congruency, allowing smooth flexion–rotation mechanics of the knee. Tears of the body are less frequent than those of the medial meniscus, but when present, they are often clinically significant in the setting of trauma or discoid meniscus variants.

The body of the lateral meniscus lies between the lateral femoral condyle and the lateral tibial plateau, forming the central midportion of the meniscus. Its mobility offers protection against injury but makes it prone to abnormalities in cases of discoid morphology or repetitive twisting stresses, which may result in clinically important tears.

Synonyms

  • Central segment of the lateral meniscus

  • Lateral meniscal body

  • Midportion of the lateral meniscus

Relations

  • Superiorly: Lateral femoral condyle articular cartilage

  • Inferiorly: Lateral tibial plateau articular cartilage

  • Anteriorly: Anterior horn of the lateral meniscus

  • Posteriorly: Posterior horn of the lateral meniscus

  • Laterally: Joint capsule, separated from lateral collateral ligament by the popliteus tendon

  • Medially: Intercondylar region and cruciate ligaments

Function

  • Load distribution: Spreads compressive forces in the lateral tibiofemoral compartment

  • Shock absorption: Reduces stress on articular cartilage and subchondral bone

  • Joint congruency: Improves conformity between femoral condyle and tibial plateau

  • Mobility: Allows smooth flexion, extension, and rotation

  • Proprioception: Contributes to neuromuscular control and stability

Clinical Significance

  • Tears: May be longitudinal, horizontal, or flap-type; less common than medial but important in trauma

  • Discoid meniscus: The body is often affected, showing thickened unstable morphology and snapping knee syndrome

  • Associated injuries: May coexist with ACL tears, chondral lesions, or cyst formation

  • Symptoms: Lateral joint line pain, mechanical popping, catching, or locking

  • Surgical importance: Repair and preservation critical to prevent degeneration and early osteoarthritis

MRI Appearance

  • T1-weighted images:

    • Normal body: low signal (dark), triangular/wedge-shaped

    • Tears: linear or complex hyperintense clefts to the articular surface

    • Parameniscal cysts: intermediate to bright rounded signal

  • T2-weighted images:

    • Normal: uniform dark wedge

    • Tears: bright linear/irregular hyperintense signals reaching surface

    • Accentuates degeneration, edema, and intrasubstance mucoid changes

  • STIR:

    • Normal meniscus: dark

    • Edema, cysts, or effusion: bright hyperintense

  • Proton Density Fat-Saturated (PD FS):

    • Normal: uniformly dark

    • Tears: bright irregular/linear signals extending to tibial or femoral surface

    • Excellent for detecting subtle discoid morphology and occult tears

  • T1 Fat-Sat Post-Contrast:

    • Normal: minimal or no enhancement

    • Scar tissue or synovitis: enhancing

    • Recurrent tears: non-enhancing (helps distinguish from scar)

  • 3D T2 SPACE :

    • Meniscus body: well-defined uniform dark band with sharp margins

    • Surrounding fluid and cartilage: bright, improving tear detection and discoid variant assessment

MRI Arthrogram Appearance

  • Contrast outlines the body of the meniscus clearly

  • Tears: contrast enters clefts or defects, appearing as bright signals

  • Distinguishes true tears (contrast entry) from degeneration (no contrast entry)

  • Particularly useful for discoid meniscus evaluation and subtle flap tears

CT Appearance

  • Non-Contrast CT:

    • Meniscus poorly visualized (soft tissue density similar to cartilage)

    • Indirect signs: joint space narrowing, subchondral sclerosis, osteophytes

    • Discoid meniscus: thickened wedge-shaped tissue between femur and tibia

  • Post-Contrast CT (standard):

    • Meniscus remains indistinct without intra-articular contrast

    • Surrounding perimeniscal soft-tissue or postsurgical changes may be inferred

CT Arthrogram Appearance

  • Contrast sharply outlines the meniscus body

  • Linear contrast-filled clefts = tears

  • Contrast extravasation = complex or displaced tears

  • Particularly valuable when MRI is contraindicated

  • Superior to standard CT for meniscal and cartilage evaluation, especially discoid variants

MRI images

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

MRI images

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

MRI images

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