Fibular collateral ligament
Ligamentum collaterale fibulare
Also known as: lateral collateral ligament, LCL
A strong, rounded cord on the lateral side of the knee from the lateral femoral epicondyle to the head of the fibula. It resists varus stress and, unlike the tibial collateral ligament, is separate from the meniscus.
Overview
The FCL runs from the lateral epicondyle of the femur to a depression on the lateral surface of the head of the fibula, where it is split by the tendon of biceps femoris. It is entirely extracapsular, separated from the capsule and the lateral meniscus by the tendon of popliteus and the inferior lateral genicular vessels. It is taut in extension and the primary restraint to varus (adduction) stress, and it forms part of the posterolateral corner of the knee with the popliteus tendon, popliteofibular ligament and arcuate ligament.
- Location
Lateral side of the knee joint.
Anatomy
- Origin
Lateral epicondyle of the femur.
- Insertion
Lateral surface of the head of the fibula.
Function
- Resists varus (adduction) stress at the knee
- With the posterolateral corner, limits external rotation and posterior translation of the lateral tibia
Clinical significance
LCL and posterolateral corner injury
Less common than MCL injury; from a varus blow to the medial knee or hyperextension. Often combined with cruciate tears and may injure the common fibular nerve (foot drop). Missed posterolateral corner injuries cause failure of ACL/PCL reconstructions.
Compiled from standard anatomy and physiology references — see the Skeletal System sources. For education only; not medical advice.