Muscle
Popliteus
Deep knee muscle controlling rotation at the start of flexion
High-yield
To begin bending an extended knee, popliteus can rotate the free tibia inward. When the tibia is fixed, the corresponding movement is outward rotation of the femur; it does not act across the ankle.
Overview
Popliteus runs obliquely across the back of the knee from the lateral femoral condyle to the upper posterior tibia. Connections with nearby meniscal and ligamentous structures help it contribute to posterolateral knee stability.
Reference facts
- Origin
- Lateral femoral condyle through its tendon, with connections to the lateral meniscus and nearby stabilizing structures
- Insertion
- Posterior proximal tibia above the soleal line
- Action
- Assists initial knee flexion and controls rotation: tibia inward when free, femur outward when the tibia is fixed
- Innervation
- Tibial nerve branches; L4-S1 is a commonly taught range
- Blood supply
- Inferior medial genicular and posterior tibial muscular branches
Clinical correlation
Injury to the posterolateral knee structures can leave rotational instability and increase loads on a cruciate ligament graft. This is a concern for combined injuries, not a certainty that every isolated popliteus injury causes reconstruction failure.
Frequently asked questions
What does the popliteus do?
Assists initial knee flexion and controls rotation: tibia inward when free, femur outward when the tibia is fixed.
What nerve innervates the popliteus?
Tibial nerve branches; L4-S1 is a commonly taught range.
Where does the popliteus attach?
Origin: Lateral femoral condyle through its tendon, with connections to the lateral meniscus and nearby stabilizing structures. Insertion: Posterior proximal tibia above the soleal line.
What is the blood supply of the popliteus?
Inferior medial genicular and posterior tibial muscular branches.