The medial collateral ligament (MCL) is a band of fibrous tissue supporting the medial (inner) aspect of the knee joint.
View of the side of the knee, showing the extent of the superficial part of the MCL.
View from the front of the knee.
Anatomy of the MCL
The medial and lateral ligament form part of the capsular structures of the knee. They are not visible from within the knee cavity. The medial collateral ligament is a band of fibrous tissue supporting the medial (inner) aspect of the knee joint. It has both a superficial and a deep component, which are separated by a 'pocket' called a bursa.
The superficial component has a connection to the posterior (rear) part of the outer rim of the medial meniscus, while the deep component is even more intimately associated with the central part.
How to tell if the MCL is torn or just sprained?
It is not always easy to tell. Both may be associated with an injury, with local pain and bruising. A ruptured MCL may produce a loud 'pop!' at the time of the incident. The knee may also feel unstable and that it cannot be trusted.
Can the collateral ligament heal without surgery?
Most MCL injuries will heal if the joint is properly protected during rehabilitation.
Treating a torn medial collateral ligament
Usually bracing or a plaster of Paris is sufficient, but in severe cases surgical repair may be indicated.