The menisci were removed from the knees of seventy autopsy subjects less
than fifty-five years old and 18.6% exhibited at least one horizontal
cleavage lesion. Seven per cent of 200 autopsy subjects showed at least one
discoid lateral meniscus, and it is suggested that neither these nor the
horizontal cleavage lesions had caused symptoms during the lifetime of each
subject. Microscopic signs of degeneration were seen in 76% of the grossly
normal medial menisci examined. Medial menisci not only have a larger
surface area than lateral menisci but are broader and thicker posteriorly.
It may be that the greater thickness of the medial meniscus posteriorly
renders it more vulnerable because there is less nutritional diffuse of
synovial fluid.