Figure 2A.

Cross-section anatomy at the level of the joint line is demonstrated. A split can be seen just in front of the superficial MCL. Layer I and II blend together along a vertical line 1-2 cm anterior to the anterior border of the superficial MCL. At the posteromedial corner of the knee, layers II and III merge forming the posterior oblique ligament, which is augmented by the insertion of the semimembranosus insertions. (From Warren LF, Marshall JL. The supporting structures and layers on the medial side of the knee, an anatomic analysis. J Bone Joint Surg Am 1979;61:58, permission granted.)

Figure 2B.

A cadaver dissection shows the slit in front of the superficial MCL (two white triangles). The ligament is long and inserts about 5-7 cm below the joint line. The posterior oblique ligament (POL) is clearly shown in continuity with the parallel fibers of the superficial MCL posteriorly.