Screw Home Mechanism- Knee Flexion/Extension (open & closed chain)

What is an open chain movement

When the distal segment moves freely around stationary proximal segment

What is a closed-chain movement

When the proximal segment moves freely around stationary distal segment

What are some open-chain knee extension movements

seated leg extensions, cable knee extensions, kicking a ball

What are some closed chain knee extension movements

squats, sit-to-stand, lunges, leg press

What are some open chain knee flexion movements

seated hamstring curls, standing hamstring curls

What are some closed chain knee flexion movements

landing from a jump, step downs

What happens to the tibia in an OPEN chain knee EXTENSION

tibia glides anteriorly and rolls anteriorly on femur

Open chain knee extension is ____ on ____

concave on convex

What happens to the femur in a CLOSED chain knee EXTENSION

femur glides posteriorly and rolls anteriorly on tibia

Closed chain knee extension is ____ on ___

convex on concave

What does the tibia do in the last 30 degrees of knee flexion to full extension of an open chain movement

tibia rotates EXTERNALLY/laterally on femur to LOCK

What does the femur do in the last 30 degrees of knee flexion to full extension of a closed chain movement

femur rotates INTERNALLY/medially on stable tibia to LOCK

What happens to the tibia in an OPEN chain knee FLEXION

tibia glides posteriorly and rolls posteriorly on femur

Open chain knee flexion is ____ on ____

concave on convex

What happens to the femur in a CLOSED chain knee FLEXION

femur glides anteriorly and rolls posteriorly on tibia

Closed chain knee flexion is ___ on ____

convex on concave

What does the tibia do in the last 30 degrees of knee extension to full flexion of an open chain movement

tibia rotates INTERNALLY/medially on femur to UNLOCK

What does the femur do in the last 30 degrees of knee extension to full flexion of a closed chain movement

femur rotates EXTERNALLY/laterally on stable tibia to UNLOCK