Lockjaw (trismus) is a painful condition that limits your ability to open your mouth all the way. It occurs when the muscles you use to chew spasm, meaning they can’t relax completely. The term ...

Falling asleep with our mouths open happens to all of us and many think it isn't such a big deal. However, there are some eye-opening things connected to open-mouth sleeping. Our facial muscles tense ...

Dear Eric: I play cards weekly with a group. One of the women sometimes chews gum during our games, noisily and with her mouth open. This is worse than fingernails on a chalkboard to me. Why do ...

Dolphins living in captivity often make an open-mouth facial expression while playing with each other. Zoomarine, Italy Bottlenose dolphins “smile” at each other while playing, making open-mouth ...