The fibular collateral ligament-biceps femoris bursa is a small bursa separating the medial surface of the anterior arm of the long head biceps femoris tendon from the medially inserting lateral collateral ligament of the knee at the level of the fibular head.
Gross anatomy
The fibular collateral ligament-biceps femoris bursa is located in the posterolateral corner of the knee with the shape of an inverted “J” separating the distal quarter of the fibular collateral ligament from the anterior arm of the long head distal biceps femoris tendon. The arc of the “J” lines the anterior and anteromedial aspect of the fibular collateral ligament hauling to the anterior arm of the short head biceps femoris tendon 1,2.
Radiographic features
MRI
With proper anatomical knowledge, it can be rarely seen on MRI as a thin hyperintense structure between the fibular collateral ligament of the knee and the anterior arm of the distal long head biceps femoris tendon 3,4.