Fibular collateral ligament
The lateral collateral ligament (LCL, long external lateral ligament or fibular collateral ligament) is an extrinsic ligament of the knee located on the lateral side of the knee. Its superior attachment is at the lateral epicondyle of the femur (superoposterior to the popliteal groove); its inferior attachment is at the lateral aspect of the head of fibula (anterior to the apex). The LCL is not fused with the joint capsule. Inferiorly, the LCL splits the tendon of insertion of the biceps femoris muscle. Structure The LCL measures some 5 cm in length. It is rounded, and is more narrow and less broad compared to the medial collateral ligament. It extends obliquely inferoposteriorly from its superior attachment to its inferior attachment. In contrast to the medial collateral ligament, it is not fused with either the capsular ligament nor the lateral meniscus. Because of this, the LCL is more flexible than its medial counterpart, and is therefore less susceptible to injury. Relations Immediately below its origin is the groove for the tendon of the popliteus. The greater part of its lateral surface is covered by the tendon of the biceps femoris; the tendon, however, divides at its insertion into two parts, which