Popliteus Visual Anatomy
The popliteus is a small, thin, flat and triangular shaped muscle. It is the deepest muscle of the posterior knee joint (posterior referring to the back of the knee) forming the floor of what is called the popliteal fossa at the back of the knee. As depicted in the sketch below the muscle originates from the lateral condyle of the femur and the posterior horn of the lateral meniscus. From these origins it travels diagonally down across the back of the knee joint inserting on the tibia below the tibial condyles, proximally (above) the origin of the soleus muscle which is the deeper of the two main calf muscles.
What Does This Little Muscle Actually Do?
For a relatively small and unknown muscle the popliteus has a couple of quite important functional roles at the knee as listed below:
- Given that its tendon has been found to be connected to the lateral capsule of the knee joint in many individuals this indicates that the muscle has a potential role in the body as a stabiliser of the back of the knee joint.
- During knee extension, there is slight outward rotation of the tibia on the femur at the knee. This rotation helps to ‘lock’ the knee joint keeping it straight without the need for as much muscle activation to keep it straight. The popliteus muscle is responsible for reversing this terminal rotation or “unlocking” the knee joint. Popliteus reverses this terminal rotation for example when standing by taking the knee out of its locked straight position at the very beginning of knee flexion.
- Popliteus is also considered to be important in resisting excessive external rotation of the tibia and therefore resisting excessive rotation at the knee again another role in assisting stabilisation of the knee.
- Via its origin and attachment off the posterior horn of the lateral meniscus it drags the lateral meniscus posteriorly during knee flexion movements, helping prevent entrapment and injury to the meniscus as the knee moves.
Disclaimer: Sydney Physio Clinic does not endorse any treatments, procedures, products mentioned. This information is provided as an educational service and is not intended to serve as medical advice. Anyone seeking specific advice or assistance regarding Popliteus Anatomy And Function should consult his or her orthopaedic surgeon, general practitioner, sports medicine specialist or physiotherapist.