Schematic of the direct and indirect entheses for the femoral and tibial insertions of the medial collateral ligament (MCL), respectively. Abbreviations are as follows: femur (F), tibia (T), fibrocartilage (FC), ligament (L), bone (B), periosteum (P), meniscus (M), joint capsule (JC), and epiphyseal plate (EP). Reprinted from Springer Anatomy and Embryology, An immunohistochemical study of enthesis development in the medial collateral ligament of the rat knee joint, Volume 194, Issue 4, 1996, 399 – 406, J. Gao, K. Messner, J. R. Ralphs, M. Benjamin, © Springer-Verlag 1996, with permission of Springer.[192]