The temporomandibular joints, also known as the TMJ, is a complex set of joints, ligaments, and jaw muscles at the base of the skull in front of the ear. We have one on each side of our head, connecting our lower jaw to our upper jaw. Each TMJ has a disc-like structure made of cartilage between the ball and the socket. This disc acts as a cushion so our jaws can open backward, forward, and even sideways. Our TMJ allows us to perform actions such as chewing, biting, yawning, and speaking.