CIRCUMFRANCE DIFFERENTIAL - No, this is not a mathematics exercise. When someone is complaining that they have great pain in an "extremity" (arms being upper extremities and legs being lower extremities), the IME doctor will often measure places on both the allegedly affected leg or arm and the corresponding leg or arm that is not affected by the condition or injury. The theory is that if a person is in pain or has lost partial use of a limb, his or her muscles will "atrophy" (gradually decrease in size) due to lack of use. If there is a perceptible difference (affected limb's muscles smaller than "normal" limb), this is felt to be having an issue (pain or disability) with that arm or leg. If there is no perceptible difference, the IME doctor will often us this fact to try to demonstrate that there is no evidence of a real problem - especially if the claim is that the problem is long-standing or chronic in nature. Of course, this method may not take into account sedentary lifestyles in which muscle mass is not well developed in both limbs in the first place. It may also not take into account that a person may curtail, lower activity levels, cease or stop most activity in an unharmed limb for a variety of reasons (fear of hurting that limb too, getting plenty of help and support from others, etc.). Bottom line here is to be aware of this test and theory, be aware that the IME doctor is not measuring you to help you get clothes that fit better, that the "test" is somewhat subjective and unscientific, and that in all events there must be a valid basis for comparison. John - jreilly@lawyers-online.us