Retrodiscal Attachment Tissues

The retrodiscal attachment tissues are the intra-articular part of the joint posterior to the condyle and disc. Functionally, this statement pertains to whether the condyle and disc are seated in the fossa or whether in fact they are seated more anteriorly. Hence, this tissue must have a volume that is very strictly defined when the condyle and disc are in centric relation, and this volume must increase instantaneously when the condyle translates anteriorly. Thus, there is a rather prominent vascular shunt in the upper part of the retrodiscal attachment, and this vascular network is contained within loosely organized fat, collagen and elastin. Perhaps because the disc tends merely to rotate against the condyle (as opposed to translating, as the disc does against the upper articular surface), there is a need for the disc to be tethered to the condyle posteriorly.

Hence, there is a stratum at the interior portion of the retrodiscal attachment that is composed of relatively inelastic and tightly packed collagen. In fact, this interior stratum of collagen blends medially and laterally with the condylodiscal ligaments, and functionally, this inferior stratum may be considered a separate ligament structure that must maintain a certain length to keep the disc and condyle in proper alignment.

Articular Cartilage

The fibrocartilage covers the intra-articular osseous surfaces. This tissue is therefore entirely dependent on synovial fluid for its nourishment. Furthermore, the joint must be free of adhesions so that the synovial fluid will have access to the articular cartilage. This tissue is generally thicker on the loaded portions of the joint surfaces. There is greater thickness of fibrocartilage on the anterosuperior condyle and on the proximal slope of the eminence. Likewise, it is these areas that receive the primary compression during normal joint movement, and hence as synovial fluid is driven into these surfaces, a thicker tissue layer can be maintained.