Vastus medialis (Musculus vastus medialis)
Educational content only — not medical advice.
Anatomy
One of the four quadriceps heads, covering the medial thigh. Its distal fibres (vastus medialis obliquus, VMO) hold the patella from the medial side and pull it medially, resisting lateral patellar drift during knee extension.
Origin & insertion
Origin: medial lip of the femoral linea aspera and medial supracondylar line. Insertion: medial border of the patella via the common quadriceps tendon.
Action
Knee extension with medial patellar stabilization.
Innervation
Femoral nerve (L2–L4)
Clinical notes
VMO weakness is a leading cause of lateral patellar maltracking and patellofemoral pain; it is rich in proprioceptors contributing to knee joint position sense.
Related structures
Educational references
FAQ
What is the role of the Vastus medialis?
One of the four quadriceps heads, covering the medial thigh. Its distal fibres (vastus medialis obliquus, VMO) hold the patella from the medial side and pull it medially, resisting lateral patellar drift during knee extension.
Why is the Vastus medialis clinically important?
VMO weakness is a leading cause of lateral patellar maltracking and patellofemoral pain; it is rich in proprioceptors contributing to knee joint position sense.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details