Sentence:  In the standing position, wth the fixation of the leg and foot on the ground, the adduction or abduction of the leg on the pelvis is a <WSD>misappearance</WSD>. In reality, there is in this position an actual adduction or abduction of the pelvis on the legs, created by the pelvis tilting laterally on the legs. 
Meaning of the word marked with <WSD> tags:  A false appearance; An instance of seeming as other than what is the true form; an illusion.