The Knee Unlocker
Today I would like to introduce to you an important muscle of the knee, the Popliteus.
To understand the popliteus, we must first understand the mechanism of the knee locking or screw home mechanism.
When straightening the knee, our femur rolls forward and slides backward on the tibia, which extends our knee from full knee flexion to 20 degrees of knee flexion. However, the final 20 degrees of knee extension require 10 degrees of external tibial rotation. This phenomenon is called a screw home mechanism. This mechanism allows us to increase our knee stability when we are standing with our knees straight.
So how do you unlock the upright knee?
The muscle responsible for unlocking the knee is called the popliteus. The popliteus originates from the back of the lateral epicondyle of the femur, that is, deep below the lateral gastrocnemius head, and attaches to the back of the tibia on the medial side. The main function of the popliteus is to internally rotate the tibia, which is to unlock the knee during the first 20 degrees of knee flexion.
In addition to unlocking the knee, the popliteus works with the gastrocnemius and hamstrings to balance the force of the quadriceps muscles, as well as to pull the lateral meniscus back when the knee is flexed to prevent it from getting caught.
The popliteus is closely related to the knee joint, so when the knee, thigh, or calf muscles are injured, don't forget to have your popliteus checked!