This procedure is used to sample muscle cells from underneath the skin of the leg. After cleaning the skin with iodine and using a local anesthetic, the doctor or nurse practitioner will make a small incision in the skin and introduce a needle under the skin to remove muscle cells. About 200-750 milligrams (less than a teaspoon size) of muscle will be removed. After the biopsy is completed, the skin will be held closed with a sterile adhesive bandage and an antibiotic ointment will be applied.