Disk - The disk acts as a cushion between the aritculating surfaces of the joint; the temporal bone and condyle of the mandible.  The disk should completely separate the joint cavity into an upper and lower portion.  With wear, however, these two compartments may communicate and the articulating surfaces of the joint may come into contact causing considerable pain and joint noise.  The disk has three main portions, an anterior, intermediate, and posterior band.
  Anterior Band - attaches to the superior head of the lateral pterygoid muscle and blends with the joint capsule.  Porovides the majority of cushion when the condyle "rolls over" the articular eminence during joint opening.
  Intermediate Band - the thinnest portion of the disk that is biconcave in shape.
  Posterior Band - the thickest portion which is attached to the medial and lateral poles of the condyle.
In general, the disk is thicker medially than laterally where the lateral pole sits higher on the ramus than does the medial pole.  One must also consider the Bilaminar Zone of Reese which is a retrodiscal tissue that is the main nourishment to the joint.  Since the joint capsule is not a vascular structure, nutrients, etc are carried through the synovial fluid.  This loose vascular tissue fills with blood when the mandible moves forward and allows for the exchange of nutrients, etc.  There are two other tissues that attach to the disk for stability that must be noted.  The superior retrodiscal lamina is an elastin fiber that attaches the disk to the temporal bone and allows the disk to stretch as it rides over the articulating surfaces during movement of the joint.  There is also an inferior retrodiscal lamina made of collagen fibers which attaches the disk to the condyle and prevents the disk from slipping off the condyle.