Since the initial employment of magnetic resonance imaging (MRI) to diagnose meniscal tears, a characteristic low-signal intensity, triangular-shaped structure has been interpreted as representing the entire meniscus. The difficulty in diagnosing meniscocapsular separations with MRI has brought attention to our lack of understanding of the appearance on MRI of the outer third of the meniscus and the meniscocapsular junction. We correlated MRIs of the meniscus in cadaver knees with histological sections and found that the low-signal, wedge-shaped structure corresponds only to the avascular (white) zone of the meniscus, whereas the high-signal zone peripheral to it corresponds to the vascularized (red) zone
