The aim of this study is to reveal the morphological property about the loose bodies (LBs) of temporomandibular joint (TMJ) by scanning electron microscope (SEM). We obtained specimens from two female cases of released loose body by surgical operation. These specimens were fixed by soaking in a mixture of 5% glutaraldehyde or 4% formaldehyde for one week. They were cut into half pieces. These specimens were observed at an accelerating voltage of 3 kV under a SEM (JSM-5500, JEOL, Tokyo). In the electron microscopic findings, it seems to be separated into two different parts as inside part and outside part. On the inside part, collagen fibers were running very densely in the same direction in an orderly neatly manner. Whereas, we observed waved collagen fibers running irregularly with many spaces on the outside part. Outside part seems to be porous pattern compared with inside part. It might be that the surface and outside part included many active fibroblasts. As results, it seems that the LBs might develop in a multi-layer style, in which fibrous tissues were piled up loosely around the inside part. The proliferating activity of LBs grows from the inside to outside of SC in TMJ.
Keywords: Loose body (LB); Scanning electron microscope (SEM); Synovial chondromatosis (SC); Temporomandibular joint (TMJ).