One of the most common jaw disorders is TMJ disorder (TMD). This condition occurs when the joints connecting the lower jaw to the skull become strained, inflamed, or injured. Healthy functioning TMJs help the mouth with almost all functions, including chewing, smiling, yawning, talking, etc. When these joints are functioning optimally, you rarely notice their presence. However, when malfunction sets in, you may experience numerous unpleasant symptoms ranging from mild to severe.