Clearing the joints

Hi i am a first year student and just been taught about clearing the joints prior to mucle length testing in one lab. I don't have a decent grasp on it and was wondering if there is any way anyone could help?!
Thanks

to 'clear' a joint is to run some tests to make sure symptoms aren't coming from them. I was always told its good practice to clear the joints above and below presenting symptoms to help ensure you're narrowing in on the right area. I guess you're teacher was just trying to say that theres no point checking something like muscle length (a possible source of symptoms) until you're sure pain isn't coming from joints around it... once you know where the symptoms are coming from it might be more appropriate to measure muscle lengths then