Lesions of the meniscus. Part I: Macroscopic and histologic findings.

Systematic macroscopic and microscopic measurements of the tibial surface of 70 menisci helped to reveal associated minimal dysplastic lesions. The normal meniscus is divided into upper and lower areas by the middle perforating bundle. Considering its high frequency, a minimal myxoid degeneration in the center of the meniscus is normal. Classic myxoid degeneration may be divided into 2 types. Type A or parameniscal cystic degeneration, and Type B or intrameniscal myxoid degeneration. The intrameniscal myxoid degeneration is a nonspecific reaction to injury. Parameniscal mucoid degeneration constitutes the substrate of lateral meniscal cysts.