Cricoarytenoid Articulation in Elderly Japanese With Special Reference to Morphology of the Synovial Tissue.

To clarify composite fibers and cells in the synovial tissues of the cricoarytenoid joint (CA joint). Routine histology and immunohistrochemistry using sagittal or nearly sagittal sections obtained from 18 elderly cadaveric specimens. The CA joint capsule was thin and contained few elastic fibers. A limited supportive ligament, namely, a thickened fascia of the posterior cricoarytenoid muscles, was sometimes evident on the lateral aspect of the CA joint. However, even in the weaker medial aspect of the joint, no marked destruction of the synovial tissues was found. The CA joint always contained synovial folds--a short medial fold and long lateral folds--but these contained no or few macrophages, lymphocytes, and blood capillaries. In 2 exceptional specimens showing inflammatory cell infiltration in the submucosal tissue of the larynx, the macrophage-rich area extended toward the capsule and medial synovial fold. The lateral aspect of the CA joint was likely to be supported mechanically by the muscle-associated tissues. Strong support of the arytenoid by muscles might reduce the degree of CA joint injury with age. However, some patients with hoarseness due to mucosal inflammation of the larynx might have accompanying synovitis and subsequent cartilage injury in the CA joint.