Different types of anchorage Intraoral AnchorageAnchorage units are present within the oral cavity. Anchorage sources can be teeth, palate, etc.Simple AnchorageWhen application of force tends to change the axial inclination of the tooth or teeth that form the anchorage unit in the plane of space in which the force is being applied.Stationary anchorageAnchor tooth or source does not move against the forces of teeth. In real sense, only the extra-oral source of anchorage like can be from headgears would be anchorage. Anchor tooth being housed in a bioactive environment would show some degree of movement and hence cannot be classified as stationary anchorage in a real sense.Reciprocal Anchorage:Teeth which are pulled against each other to close spaces. Midline diastema in the upper arch with elastic arch. Cross elastics to correct molar cross-bite. Arch expansion using a midline screw. The molar rotator. Single or Primary AnchorageThe tooth to be moved against a tooth which can have greater alveolar support area. Like a molar along with adjacent premolars used to align another molar.Compound AnchorageThe use of more teeth with greater anchorage potential to move a tooth or group of teeth with lesser support. Like in the fixed orthodontic appliances retracting incisors using loop mechanics.Reinforced AnchorageReinforcing of anchorage units by use of more than one type of resistance units. Like headgears along with routine fixed mechano-therapy or (extra-oral anchorage and intra arch compound anchorage)Key Concept:  Since the figure shows the movement of both the units towards each other, this doesn’t fit the definition of stationary anchorage.