The vastus medialis extends distally as the VMO (vastus medialis oblique) which has distinct fibres angled 50-55 degrees to the femur and inserts on the medial patella. The VMO provides the medial patellar stabilisation force.
| Origin | Intertrochanteric line, linea aspera — medial lip (throughout the length) |
|---|---|
| Insertion | Medial base of the patella and quadriceps tendon — medial aspect |
| Nerve Supply | Femoral nerve (L2, L3, L4) |
| Blood Supply | Descending branch of medial circumflex femoral artery |
| Actions | Extends the knee; Provides medial patellar traction — prevents lateral patellar subluxation |
|---|
VMO atrophy is the earliest indicator of knee pathology and is associated with patellofemoral pain syndrome. Selective VMO strengthening (terminal knee extension, step-ups) is the cornerstone of patellofemoral rehabilitation. VMO is preferentially activated at full extension and acts as a medial patellar brake.
Palpated as the medial quadriceps bulk and specifically at the superomedial patellar pole during terminal knee extension.
Selective vastus medialis and VMO atrophy contributing to lateral patellar tracking and anterior knee pain, targeted by isolated VMO strengthening exercises.
