Morphologic study of the lateral and medial collateral ligaments of the human knee.

The collateral ligaments of the knee are important in maintaining knee stability. Numerous studies have been described the morphology and function of the ligaments of the knee. However, little data was given about the lateral and medial collateral ligaments simultaneously. The objective of the present study was to compare the morphology of the lateral (LCL) and medial (MCL) collateral ligaments in human knees. We dissected 34 cadaver knees and examined the size, attachment and inclination of the LCL and the MCL. In both of them, the posterior bundle was longer than that of the anterior bundle. The anterior and posterior bundles of the MCL were longer than that of the LCL. The proximal attachment of the MCL situated more anterior and superior than that of the LCL. As compared with the LCL, the distal attachment of the MCL located a little forward and inferior. The longitudinal diameter of the attachment of ligaments was longer than the transverse one, except for the proximal attachment of the MCL. The size of the attachments of the MCL was larger than that of the LCL except for the longitudinal diameter of the proximal attachment. At full extension of the knee, the inclination of the MCL was backward, while that of the LCL was forward. These data showed that the LCL and MCL had the different structural properties. It may provide a better understanding of the function of the collateral ligaments.