Three layers of the medial capsular and supporting structures of the knee: MR imaging-anatomic correlation

The authors used a three-layer approach to correlate the appearance of the capsule and ligaments of the medial side of the knee on magnetic resonance (MR) images with corresponding anatomic slices. ATR images of six fresh cadaveric specimens were obtained by using a proton-density-weighted fast spin-echo sequence with a 256 x 512 matrix. Specimens were frozen and sliced with a band saw into 3.0-mm-thick sections that corresponded to the MR images. Three layers were depicted on both anatomic slices and MR images. Layer 1 consisted of the deep crural fascia; layer 2, the superficial portion of the medial collateral ligament (MCL); and layer 3, the capsule, the deep portion of the MCL, the meniscofemoral and meniscotibial extensions of the deep portion of the MCL, and the patellomeniscal ligament. Along the anterior aspect of the medial side of the knee, layer 1 was fused with layer 2; along the posterior aspect of the knee, layer 2 was fused with layer 3.