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Distal vastus medialis tendon

The distal vastus medialis tendon represents the terminal portion of the vastus medialis muscle, one of the four quadriceps femoris muscles. Its most distal fibers, particularly the vastus medialis obliquus (VMO) portion, insert onto the patella and play a crucial role in patellar stabilization. The tendon blends with the quadriceps tendon and medial retinaculum, contributing to both dynamic and passive control of patellar tracking.

It is of high clinical significance in patellofemoral instability, quadriceps tendon tears, and post-surgical rehabilitation.

Synonyms

  • Vastus medialis obliquus (VMO) tendon

  • Distal quadriceps tendon (medial portion)

  • Medial quadriceps tendon

Origin and Insertion

  • Origin (muscle fibers): Arises from the intertrochanteric line and medial lip of linea aspera of femur, extending distally

  • Tendon course: Distal fibers become tendinous near the knee joint

  • Insertion: Inserts into the superomedial border of the patella, blending with the quadriceps tendon and medial patellar retinaculum

Relations

  • Anteriorly: Subcutaneous tissue and skin overlying the medial knee

  • Posteriorly: Femoral condyle, suprapatellar fat pad, synovial lining of the knee joint

  • Medially: Medial patellar retinaculum and medial collateral ligament (MCL)

  • Laterally: Quadriceps tendon blending centrally and with vastus intermedius fibers

  • Inferiorly: Patella and patellar tendon

Nerve Supply

  • Femoral nerve (L2–L4) via branches to vastus medialis

Arterial Supply

  • Femoral artery (muscular branches)

  • Descending genicular artery

  • Superior medial genicular artery

Venous Drainage

  • Femoral vein and genicular venous plexus

Function

  • Provides extension of the knee joint via quadriceps mechanism

  • Distal VMO fibers exert medial stabilizing pull on the patella

  • Prevents lateral patellar dislocation during terminal knee extension

  • Assists in patellofemoral joint alignment during locomotion

MRI Appearance

T1-weighted images:

  • Tendon appears as a low-signal linear structure inserting on the patella

  • Adjacent fat planes and retinaculum appear bright, delineating tendon margins

T2-weighted images:

  • Normal tendon shows uniformly low signal

  • Tendinosis, partial tear, or inflammation shows focal or diffuse hyperintensity within or around tendon

STIR (Short Tau Inversion Recovery):

  • Normal tendon is low signal

  • Pathology (strain, tear, enthesopathy) appears bright hyperintense, particularly at patellar insertion

Proton Density Fat-Saturated (PD FS):

  • Normal tendon is low signal

  • Injury, microtears, or tendinopathy appear hyperintense, best sequence for subtle abnormalities

T1 Fat-Sat Post-Contrast:

  • Normal tendon: minimal or no enhancement

  • Tendinitis or enthesitis: linear or diffuse enhancement

  • Partial tear: focal enhancement at defect margins

  • Abscess or inflammatory bursitis: rim enhancement with central low signal

CT Appearance

Non-Contrast CT:

  • Tendon seen as a linear soft tissue density attaching to patella

  • Calcific tendinopathy: focal hyperdense deposits near patellar insertion

  • Acute tear: irregular tendon margins with associated swelling or hematoma

Post-Contrast CT:

  • Normal tendon shows little or no enhancement

  • Inflammation or tendon pathology may show surrounding soft tissue enhancement

  • Abscess or inflammatory changes: rim-enhancing fluid collections adjacent to tendon

MRI images

distal vastus medialis tendon axial cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

MRI images

distal vastus medialis tendon sagittal cross sectional anatomy 3T MRI AI enhanced radiology anatomy image-img-00000-00000

CT image

distal vastus medialis tendon ct axial image

CT image

distal vastus medialis tendon sagittal image