| | Conditions Treatments | Muscle Strain What does the popliteus muscle do? Flexes and unlocks the knee, especially when the knee is flexed (inwardly rotates the tibia when knee flexed). Muscle Strain - Related Articles Protein Powder Plan & Migraine Headaches Dangers in Using Colloidal Silver Side Effects of Too Much Probiotics Dexamethasone for Treatment of Pediatric Asthma Central Nervous System Disorders When does a child receive measles booster shot? What are the disadvantages of asbestos?