The purpose of this paper is to report morphological features of the cells in the human posterior longitudinal ligament, including its attachment to the vertebral bodies, and of the cultured cells derived from PLL. We used the transmission electron microscopy to observe the cells. Far from its vertebral attachment, the main constituent cells in PLL are fibroblasts. The closer to the vertebral bodies fibroblasts become degenerative, and chondrocytes are observed in the irregular collagen fibers. The closer still more, calcium deposits on the collagen fibers, and osteocytes become the dominant cells. Compared with these three types of cells fibroblast, chondrocyte, and osteocyte in PLL, the cultured cells resemble fibroblasts.
