ACL, PCL, MCL, LCL – What Are They & Where Are They Located?

August 29, 2018

Most of us probably know someone who has had an ACL tear/reconstruction, or have watched a football or basketball player be carted off the field or court with what the announcers assume is an ACL injury.  Just what is an ACL and where is it located; and did you know that you also have a PCL, MCL, and LCL – sounds like an alphabet soup game!  These are the 4 main ligaments or tough bands of tissue in the knee.

ACL is anterior cruciate ligament which connects the thigh bone to the shin bone. It keeps the tibia (shin bone) from sliding too far forward.  It is the most commonly injured knee ligament among athletes.  70% of ACL tears as the result of non-contact injuries, 30% are the result of direct contact.  Women are 4-6 times more likely than men to experience an ACL tear.  Most people who sustain an ACL tear will undergo surgery to repair the tear; however, some people avoid surgery by modifying their activity to not put so much stress on the knee. 

The PCL is the posterior cruciate ligament which also links the thigh bone to the shin bone.  It is the ligament that prevents the tibia (shin bone) from sliding too far backwards.  The PCL helps maintain the tibia in position below the femur (thigh bone). PCL injuries account for about 20% of knee injuries; these are usually related to car accidents.  

MCL is another of the four ligaments, the medical collateral ligament. It links the thigh bone to the shin bone on the inside of the knee.  The MCL resists widening of the inside of the joint or prevents “opening-up” of the knee. It is usually injured when the outside of the knee is struck, causing the outside to buckle and the inside to widen. The MCL tear may be an isolated injury or it may be part of a complex injury to the knee.

The final ligament is the LCL or lateral collateral ligament. It connects the thigh bone to the fibula, the smaller bone of the lower leg on the outer side of the knee. The LCL helps to prevent excessive side movement of the knee joint.  If the LCL is torn, the knee joint may move too far side-to-side when stressed. It is commonly torn during sports activities and this happens when the knee bends inwards excessively and the LCL is stretched too far. 

Knee ligament injuries are hard to prevent, but you can take some precautions that may make them less likely.  Keep the muscles around your knee strong with regular stretching and strengthening, warm up with light activities before taking part in tougher ones, maintain flexibility, and make changes slowly – don’t suddenly make your workouts a lot more intense. 

Should you sustain an injury or have knee pain that does not seem to be improving, you should come in for an evaluation with our orthopedic providers.  No referral is necessary.  Call 515-955-6767.   


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