The knee joint is mainly with four ligaments. The function is to keep knee stability. It is PCL, ACL, MCL & LAL respectively. PCL & ACL joins the thigh and shinbone and the form of crossing. The purpose is to keep the stability of the front and rear of knee joint. MCL joins the thigh and shinbone inside. LAL joins thigh and fibula. MCL & LAL helps the stability of horizontal displacement of knee joint. MCL & LAL helps the stability of horizontal displacement of knee joint.
Human gait is divided into six parts:
- heel strike
- full forefoot load
- mid-stance
- heel life
- toe off
- mid-stance
The human walks to utilize muscles to let the leg be swung and reached the purpose to advance.
The knee joint will have phenomenon moved forward when mid-stance to heel strike. It causes the injury that PCL function prevents moved forward. If move forward and backward the knee joint happens.
ACL prevents the knee joint to move backward when toe off to mid-stance. The knee joint bears the weight of the body when heel strike to heel life. The knee joint offers the equilibrium body. The knee joint will bear to the strength of different directions. MCL & LAL helps steady right & left direction of the knee joint.