Final answer:
Jaw pain when opening the mouth could be a symptom of TMJ dislocation or temporomandibular joint disorder, resulting from various causes such as arthritis, cartilage wear, muscle fatigue, or a jaw injury. Additionally, pain can stem from muscle fatigue due to persistent teeth clenching. Treatment options include pharmacologic agents, bite guards, and other therapies.
Step-by-step explanation:
When you experience pain in your jaw upon opening your mouth, it could be due to a dislocation of the TMJ (temporomandibular joint). This dislocation can happen if the mouth is opened too widely, as in taking a large bite, or due to a blow to the jaw, with the mandibular condyle moving ahead of the articular tubercle.
Another condition possibly causing your jaw pain is temporomandibular joint disorder, often referred to as TMJD or TMD. This disorder could stem from arthritis, wearing of the articular cartilage, muscle fatigue from excessive use or teeth grinding, damage to the articular disc in the joint, or a jaw injury.
TMJD symptoms are not limited to jaw pain but can also include headaches, difficulty chewing, or a locked jaw. To treat TMJD, various therapies like pharmacologic agents, bite guards, or other interventions may be recommended.
In addition, muscle fatigue caused by persistent clenching of the teeth, often due to stress, can induce pain in the jaw as well as stress headaches. This occurs because the masseter muscles, which are responsible for closing the jaw, exert very large forces especially on the back teeth where they have a mechanical advantage greater than 1.
Movement at the TMJ is quite intricate, involving a combination of gliding and hinging motions of the mandible. When opening the mouth, these actions result in a net forward and downward motion of the mandible. The TMJ is fortified by an extrinsic ligament that connects the mandible to the skull, helping to control and limit the movement of the joint.