The vastus medialis oblique (VMO) refers specifically to the distal oblique fiber bundle of the vastus medialis muscle whose fibers run at 50-55 degrees to the quadriceps axis, inserting directly onto the medial patella. It is the principal dynamic medial patellar stabilizer in terminal knee extension. VMO atrophy or inhibition is associated with patellofemoral pain syndrome, patella alta, and patellar instability.
| Origin | Medial intermuscular septum and medial supracondylar ridge of the femur; the distal oblique fibers arise from the adductor magnus tendon |
|---|---|
| Insertion | Medial border of the patella and the medial patellar retinaculum; the oblique fibers insert at 50-55 degrees to the quadriceps tendon axis |
| Nerve Supply | Femoral nerve (L2-L4) |
| Blood Supply | Descending genicular artery; medial superior genicular artery |
| Actions | Extends the knee; the oblique fibers specifically resist lateral patellar displacement by pulling the patella medially during terminal knee extension; provides the primary dynamic medial restraint to the patella in the last 10-15 degrees of extension |
|---|
VMO strengthening is the cornerstone of conservative treatment for patellofemoral pain syndrome and patellar instability. Straight-leg raises, terminal knee extensions, and VMO-biased closed-chain exercises selectively activate the VMO. Biofeedback EMG training can improve VMO:VL activation ratio. After total knee arthroplasty, restoring VMO strength is essential for patellar tracking. The medial parapatellar TKA approach requires careful VMO repair to restore patellar stability post-operatively.
Reflex inhibition of the VMO in the presence of even small knee effusions allows the dominant vastus lateralis to lateralize the patella, worsening patellofemoral contact pressure; EMG-biofeedback-guided VMO training restores the VMO:VL timing ratio and reduces lateral patellar tilt in patellofemoral pain syndrome.
This website uses cookies to enhance your experience. Some are essential for site functionality, while others help us analyze and improve your usage experience. Please review your options and make your choice.
If you are under 16 years old, please ensure that you have received consent from your parent or guardian for any non-essential cookies.
Your privacy is important to us. You can adjust your cookie settings at any time. For more information about how we use data, please read our privacy policy. You may change your preferences at any time by clicking on the settings button below.
Note that if you choose to disable some types of cookies, it may impact your experience of the site and the services we are able to offer.
Some required resources have been blocked, which can affect third-party services and may cause the site to not function properly.
This website uses cookies to enhance your browsing experience and ensure the site functions properly. By continuing to use this site, you acknowledge and accept our use of cookies.
