Trismus, or lockjaw, is a painful condition in which the jaws do not open fully. As well as causing pain, trismus can lead to problems with eating, speaking, and oral hygiene.
Trismus occurs when a person is unable to open their mouth more than 35 millimeters (mm)Trusted Source. It can occur as a result of trauma to the jaw, oral surgery, infection, cancer, or radiation treatment for cancers of the head and throat. Most cases of trismus are temporary, typically lasting for less than 2 weeks. Trusted Source, but some may be permanent. In this article, we explore the causes and symptoms of trismus. We also look at the current treatment options for this condition.
Causes:
Trauma and inflammation are possible causes of trismus.
Trauma:
Injury or damage to the jaw can lead to trismus. Examples of such trauma include fractured jawbones or tissue damage following dental surgery.
Others include:
•contusion of the temporomandibular joint (TMJ)
• hematoma, which is a collection of blood outside of blood vessels
• injury to the muscles of mastication, which people use when chewing
Inflammation:
Some medical conditions that cause inflammation in the mouth may cause trismus. One example is pericoronitis, which is inflammation of the soft tissue around a tooth, potentially leading to an impacted molar.
Others include:
• arthritis in the jawbones
• scleroderma, which is an autoimmune disease that affects connective tissue
• soft tissue fibrosis, which occurs when excess fibrous connective tissue forms
Courtesy: Mayo Clinic