How do you decide where to take the muscle biopsy from?

Middle: Generally we don't want a muscle that's too far gone, or one not really affected. We try to choose one in the middle. And not too visible. Often we use a thigh muscle or triceps, if either fits the bill. Btw, proper handling of the specimen is important (freezing technique) so make sure the clinic does this regularly. Also, a general pathologist is rarely qualified. Send to subspecialist.

Muscle biopsy: Most random muscle biopsies are done in easily accessible, large muscle groups. Generally the lateral thigh or calf.