Altering the resting posture of the mandible changes the position of its condyle within the mandibular fossa of the temporal bone.
A posteriorly displaced condyle could, in theory, compress the delicate retrodiscal tissues, creating inflammation and muscle spasm.
Spasm in the lateral pterygoid muscle may be a natural protective mechanism to protrude the mandible away from the compressed retrodiscal tissues.
Chronic spasm within this muscle may, however, abnormally position the disc anterior and medial to the condyle.
This situation may predispose a person to a condi tion of internal derangement of the disc. Although the data suggest an association between abnormal craniocervical posture and dis- orders of the temporomandibular joint(TMJ), 40 it is difficult to find supporting literature that unequivocally proves such a cause-and effect relationship