Temporomandibular joint (TMJ): The joint that hinges the lower jaw (mandible) to the temporal bone of the skull. It is one of the most frequently used joints in the entire body, moving whenever a person eats, drinks, or talks. SLIDESHOW Heart Disease: Causes of a Heart Attack See Slideshow From Healthy Resources 10 Rheumatoid Arthritis SymptomsWhat Is Exocrine Pancreatic Insufficiency?Cholangiocarcinoma (Bile Duct Cancer) Featured Centers What Are the Best PsA Treatments for You?Understanding Biologics 10 Things People With Depression Wish You Knew Health Solutions From Our Sponsors Shot-Free MS Treatment Your Child and COVID-19