Fibrous cartilage is formed by chondrocytes strung between parallel collagen fibers of varying diameter, usually quite thick.
It can be concluded that this type of cartilage, which combines collagen fibers and components of the cartilaginous extracellular matrix, has a high capacity for resistance to mechanical pressure, torsion, and tension. It is, therefore, a very strong structure, which explains its location in areas highly subject to physical forces: intervertebral discs, pubic symphysis, tendon insertions into bones, the temporomandibular joint, and the hip joint.
The image above shows a small magnification of a portion of an intervertebral disc, where collagen cells and fibers can be seen. In this type of cartilage, the extracellular matrix is not basophilic, as in other types of cartilage, as it is formed mainly by the protein collagen, which is acidophilic, staining pink after HE.
In the higher magnification (bottom figure) of an intervertebral disc, chondrocytes are aligned between thick acidophilic collagen fibers. It is clear that the chondrocytes are located in small gaps.
Chondrocytes are highlighted in blue and collagen fibers in pink.
The differential diagnosis between fibrocartilage and tendon can be made by the cells that constitute them: elongated fibroblasts in tendon and chondrocytes in cartilage.
Fibrocartilage. Staining: HE. Magnification: small.
