Synovial plicae of the knee.

Synovial plicae are remnants of synovial tissue found in the adult knee which in early development partitioned the joint into three compartments. The most common types are the suprapatellar, medial patellar, and infrapatellar plicae. Although they are normally found in up to 60% of adult knees, plicae may become pathologically thickened and symptomatic, resulting in the "plicae syndrome." In addition, persistence of these structures in their embryonic form as complete septa may give rise to a variety of intra-articular compartmental syndromes, medial patellar, and infrapatellar plicae. Although they are normally found in up to 60% of adult knees, plicae may become pathologically thickened and symptomatic, resulting in the "plicae syndrome." In addition, persistence of these structures in their embryonic form as complete septa may give rise to a varietellar, medial patellar, and infrapatellar plicae. Although they are normally found in up to 60% of adult knees, plicae may become pathologically thickened and symptomatic, resulting in the "plicae syndrome." In addition, persistence of these structures in their embryonic form as complete septa may give rise to a variety of intra-articular compartmental syndromes. This report describes the anatomy and embryology of synovial plicae, as well as the clinical and radiographic findings associated with abnormal plicae in a variety of clinical entities.