Popliteus is the only muscle of the knee proper, unlocking the fully extended knee. Its femoral origin in the popliteal sulcus and posterior tibial insertion initiate the 5 degrees of internal rotation needed to begin flexion from full extension.
| Origin | Lateral femoral condyle — popliteal sulcus; Posterior horn of lateral meniscus |
|---|---|
| Insertion | Posterior tibia above the soleal line — medial two-thirds |
| Nerve Supply | Tibial nerve (L4, L5, S1) |
| Blood Supply | Popliteal artery — inferior genicular arteries |
| Actions | Unlocks the fully extended knee by initiating internal tibial rotation; Retracts the lateral meniscus during knee flexion; Resists posterior tibial translation |
|---|
Popliteus tendinopathy produces posterolateral knee pain worse on downhill walking. The tendon is the landmark in the posterolateral corner and reference for tibial external rotation (dial test) and PLC reconstruction. Avulsion produces the arcuate fracture pattern.
Not directly palpable — the posterior knee fossa is palpated with the knee flexed.
Posterolateral knee pain at the lateral femoral condyle sulcus in runners and downhill hikers, managed by eccentric strengthening and targeted injection.
