Temporo-mandibular joint (i.e. jaw joint) is a joint formed between a skull bone called temporal bone and a sharp pointy part of mandible called condyle. The mandible has no bony connection but instead suspended and held in place by the muscles of mastication (chewing), capsule and ligaments that are like the guide wires. It is located just immediately in front of your ear canal.
Place your index fingers in the ear canal and then open and close your month. You can feel the condyles move and glide away. The assessment of temporomandibular joint dyscunction involves finding out which of the abovementioned structure is the most problematic and treat it accordingly.