The variations in size of the short lateral ligament, the occasional absence of the short lateral ligament, and the reasons for the presence of the fabellofibular ligament are indicated in this study. The short lateral ligament and the fabellofibular ligament are apparently homologous structures corresponding to a similar strongly developed structure in the kangaroo and connected with the function of extension of the knee.
The fabellofibular ligament is apparently always present when a lateral fabella is found in man. On surgical exposure of the human knee joint, when there is roentgenographic evidence of a fabella, the fabellofibular ligament may be found as a well developed ligament. It is located just posterior to the area of insertion of the tendon of the biceps muscle, between the biceps and lateral gastrocnemius, whereas the lateral collateral ligament is located anteriorly, in front of the biceps tendon.