Lesions of the meniscus. Part II: Horizontal cleavages and lateral cysts.

Horizontal cleavages and lateral cysts were examined in a series of 70 menisci. The horizontal cleavage (HC) is the most frequent form of tear, occurring most often in the middle third of the lateral meniscus. Horizontal cleavages which reach the base of the meniscus triangle connect with parameniscal cysts. Extension of the horizontal cleavage into the parameniscal region seems to be, therefore, the cause of cyst formation.