Screw-Home Mechanism of the Knee EXPLAINED

The video explains the screw home mechanism of the knee, focusing on the differences between open and closed chain knee extensions. In open chain movements, the tibia rotates externally relative to the femur near full extension, influenced by the shape of the medial femoral condyle, tension in the ACL, and the pull of the quadriceps. In closed chain movements, such as squats, the femur rotates internally relative to the tibia. Understanding these mechanisms is crucial for proper knee mobilization and exercise execution.

In an open chain knee extension, which bone is considered the mobile bone?

• Fibula

• Tibia

• Patella

• Femur

What additional movement occurs in the knee joint during open chain near terminal knee extension?

• Tibial internal rotation

• Tibial external rotation

• Femoral internal rotation

• Femoral external rotation

Which structure contributes to the external rotation of the tibia during open chain knee extension?

• Lateral meniscus

• Anterior cruciate ligament

• Posterior cruciate ligament

• Medial collateral ligament

What role do the quadriceps play in the screw home mechanism during open chain knee extension?

• They pull the tibia medially

• They pull the tibia laterally

• They stabilize the femur

• They rotate the femur externally

In a closed chain knee extension, which bone is primarily mobile?

• Patella

• Tibia

• Femur

• Fibula

During a squat, what type of rotation does the femur undergo relative to the tibia?

• Lateral rotation

• Internal rotation

• No rotation

• External rotation

What is the primary difference in the screw home mechanism between open and closed chain movements?

• There is no difference

• The tibia rotates internally in both

• The femur rotates externally in both

• The mobile bone changes between the tibia and femur