Pemberton's sign was named after Hugh Pemberton, who characterized it in 1946. The Pemberton maneuver is a physical examination tool used to demonstrate the presence of latent pressure in the thoracic inlet. The maneuver is achieved by having the patient elevate both arms (usually 180 degrees anterior flexion at the shoulder) until the forearms touch the sides of the face. A positive Pemberton's sign is marked by the presence of facial congestion and cyanosis, as well as respiratory distress after approximately one minute.