Medial alar fold

The medial alar fold is a longitudinal fold just medial to the patella. It is an inconsistently present fold that is wide and very soft. Triangular at the cross-section, it is thought to be the folding of synovium in the relaxed position of retinaculum. The medial alar fold has also been called the plica alaris elongata, plica alaris, alar ligament, semi-lunar fold, mediopatellar pseudomeniscus, and patellar meniscus.