TMJ stands for tempero-mandibular-joint, or in layman’s terms – your jaw. Your jaw is made up of 2 bones: the temporal bone – which is a section of your skull (which is actually made up of many bones, not just one big one) – and the mandible, which is the bone that makes your chin and holds your bottom teeth.
There are many muscles that surround the jaw and attach to it. It’s actually quite a complex little joint.