Facet joint menisci of the cervical spine: correlative MR imaging and cryomicrotomy study.

An analysis of the cervical facet joint menisci was done in which cryomicrotomy sections were correlated with magnetic resonance (MR) images. In parasagittal anatomic sections in ten cadavers, 10-69 years of age at death, four types of meniscus were defined. Type 1 was a thin washer of dense connective tissue covering 50% or more of the joint space. Type 2 in sagittal section appeared as a wedge of connective tissue containing collagen in the tapering free edge and fat in the peripheral portion attached to the joint capsule. Type 3 had no meniscuslike connective tissue extending into the joint. Type 4 had irregular, thick masses of collagen, fat, and cartilage in the periphery of the joint space. Menisci in the child were predominantly type 1. In adults type 2 menisci predominated at C1-2 and type 3 in the lower cervical facet joints. The few type 4 menisci found were in association with facet joint degeneration. Types 2 and 4 menisci could be demonstrated with MR imaging. In MR images the collagenous portion of the menisci were of low signal intensity, and the fat was of higher signal intensity. Few menisci conform to the traditional anatomic description.