Postures, such as standing, are largely reflex in origin, dependent upon involuntary muscle contraction in antigravity muscles. Interference with such reflex activity impairs normal standing. Postural and righting reflexes depend on the integration of labyrinthine, proprioceptive, exteroceptive, and visual stimuli, mostly in the brainstem but also involving the cerebral cortex. However, abnormalities in these reflexes are of relatively little diagnostic value except in infants.
One exception is extrapyramidal disease (parkinsonism, Huntington’s disease, but not idiopathic dystonia) in which impairment or loss of postural reflexes may be observed. In the "pull test" the examiner stands behind the patient, who is standing comfortably, and pulls briskly on the shoulders; this may provoke repetitive steps backward (retropulsion, festination) or even en bloc falling, due to the failure of reflex muscle contraction necessary to maintain equilibrium. Pushing the patient may likewise provoke propulsion or festination, but this maneuver is less safe since the examiner will not be placed to catch the patient should they begin to topple over.