The masseter muscle is one of the muscles of mastication (chewing) . It is the strongest muscle based on its weight or pressure bearing capacity. With all the muscles of the jaw working together, it can close the teeth with a force as great as 55 pounds (25 kilograms) on the incisors and 200 pounds (90.7 kilograms) on the molars.
The function of the masseter muscle is to elevate the lower jaw causing a powerful jaw closure.
In 1986, Richard Hofmann of Lake City, Florida, achieved a bite strength of 975 pounds (442 kilograms) for two seconds, setting a Guinness World Record.
The masseter muscle is also known as the 'thinker' because of how people sometimes rest their hand on it when they are in deep conversation.