Subjects to the right and below:

• Hyperfunctional facial lines were evaluated in identical 38-year-old twin sister.
• The "treated" twin had received Botox® injections in the forehead region and the glabellar region approximately 2-3 times each year over the last 13 years. She had also received a total of 2 treatments with Botox® n the crow's feet area in the last 2 years. She was last treated with Botox® more that 4 months before the forehead, glabellar, and crow's feet "at rest" photographs were taken and 7 months before the crow's feet "when smiling" photographs were taken.
• The "untreated" twin received only 2 treatments with Botox® — both in the forehead and glabellar regions. The first of these was administered 7 years ago and the second was administered 3 years ago.