Origin and Insertion (xlas)

The names imply that a muscle starts at "origin" and ends at "insertion". However, you may still confuse these two, so here is a general guideline I found to be helpful. 
 
 The origin part usually does not move (or moves less than the insertion part) when the muscle is flexed.  
 The insertion part usually moves when the muscle is flexed. 
 
 Also note that origin and insertion areas always refer to tendons that connect a muscle and a bone. There are no muscles that connect directly to a bone.