Elastic fibers in the human temporo-mandibular joint disc

The elastic fiber content of 12 articular discs, removed from 12 patients with complete anterior or medio-anterior disc displacement, was examined. Eight to 12 sagittal sections (3 microm each) were acquired for each disc and stained with modified resorcin-fuchsin for visualization of elastic fibers. The program "CUE-2 Image Analyzer Morphometry" digitized all sections with 800x magnification, calculated the elastic fiber content and reconstructed it 3-dimensionally. The calculated volume density of the entire disc was a mean x(tot)= 0.339 +/- 0.060% of the total tissue. The highest fiber content of 2-4% was found in the posterior area at the transition to the bilaminar zone. 61% of the elastic fibers were located in the bilaminar zone, 10% in the posterior, 2% in the intermediary and 26% in the anterior band. There were substantially more fibers in the cranial part of the posterior region and at the medial edge as compared to the mean fiber distribution of the posterior band and the bilaminar zone. A third of these fibers were found in the inferior layer, particularly in the lateral part. Exactly the opposite fiber distribution was seen in the anterior band. The fibers frequently appeared in the caudal layer, especially in the lateral periphery, but there were fewer fibers in the medial cranial layer.