**7.1 Types of movements**

Movements have been extensively studied at the level of the occlusal interface, being Ulf Posselt one of the first to describe motion in three dimensions. Condylar rotation and translation of the condyle-disc assembly, in most cases, begin simultaneously. On average, condylar rotation increases or decreases linearly by approximately 2°/mm of anterior or posterior translation during opening or closing, respectively [8, 16].
