Musculus quadriceps femoris -- vastus medialis
The medial component of the quadriceps. Important for medial stabilization of the patella and smooth stifle extension.
Origin: Medial surface of the proximal femur
Insertion: Medial patellar ligament and tibial tuberosity
Action: Extends the stifle; medially stabilizes the patella
Innervation: Femoral nerve (L4-L5)
Weakness of the vastus medialis contributes to medial patellar subluxation and upward fixation of the patella.
Weakness of the vastus medialis contributes to medial patellar subluxation and upward fixation of the patella. Signs include: Intermittent locking of the hindlimb in extension; catching or clicking at the stifle; improved with quadriceps-strengthening exercises (hill work, backing).
See the Vastus Medialis on our interactive 3D horse model. Open 3D Model