Lower limb
Popliteus
Musculus popliteus
- Origin
- Lateral femoral condyle (and the lateral meniscus)
- Insertion
- Posterior surface of the tibia, above the soleal line
- Function
- 'Unlocks' the knee joint by internally rotating the tibia relative to the femur at the onset of flexion; stabilizes the posterolateral knee
- Innervation
- Tibial nerve (L4-S1)
- Movement & chain
- Initiates the internal rotation of the tibia that 'unlocks' the knee from full extension, essential when starting knee flexion, for example when squatting.
- Palpation
- Barely palpable directly due to its deep location in the popliteal fossa beneath the gastrocnemius; can be tested indirectly via resisted internal rotation of the tibia in slight knee flexion.
- Clinical
- Overuse causes posterolateral knee pain (popliteus tendinopathy), often with downhill walking; the muscle is also important in posterolateral knee instability.
- Segmental innervation
- L4-S1.
- In clinical practice
- Frequent repositioning to prevent trochanteric and heel pressure ulcers; ensure hip dislocation precautions in total hip arthroplasty patients.
- Region in the model
- Lower limb