It is a broad, flat, membranous band, situated slightly posterior on the medial side of the knee joint.

[3] The fibers of the posterior part of the ligament are short and incline backward as they descend; they are inserted into the tibia above the groove for the semimembranosus muscle.

Crossing on top of the lower part of the MCL is the pes anserinus, the joined tendons of the sartorius, gracilis, and semitendinosus muscles; a bursa is interposed between the two.

An MCL injury can be very painful and is caused by a valgus stress to a slightly bent knee, often when landing, bending or on high impact.

The most common knee structure damaged in skiing is the medial collateral ligament, although the carve turn has diminished the incidence somewhat.

The center and the guards are the most common victims of this type of injury due to the grip trend on their cleats, although sometimes it can be caused by a helmet striking the knee.

[6] As a result, more severe grade III and IV injuries to the MCL that lead to ongoing instability may require arthroscopic surgery.