Trismus
Restricted mouth opening from muscle spasm or other causes.
Trismus is a condition of restricted mouth opening, initially described in the context of tetanus. It can result from spasm of the masticatory muscles or from various other causes, and temporary trismus is far more common than permanent trismus. The condition interferes with eating, speaking, and oral hygiene, and may increase the risk of aspiration due to difficulty swallowing.
Quick Facts
- Normal mouth opening range
- 35–45 mm / 0.115–0.148 ft
- Mild trismus interincisal opening
- 20–30 mm / 0.066–0.098 ft
- Moderate trismus interincisal opening
- 10–20 mm / 0.033–0.066 ft
- Severe trismus interincisal opening
- less than 10 mm / 0.394 in
- Normal lateral movement
- 8–12 mm / 0.026–0.039 ft
- Normal protrusive movement
- approximately 10 mm / 0.394 in
- Etymology
- Greek trigmos/trismos meaning 'a scream; a grinding, rasping or gnashing'
Facts from the source article.
Did You Know?
- Treatment for trismus may include speech therapy for swallowing difficulty and mouth opening restrictions.
- Splints have been used in the management of trismus.
Definition
Trismus is a condition involving painful difficulty opening the mouth, usually from muscle spasm, though it can describe any cause of limited mouth opening. The older term lockjaw was sometimes used for both trismus and tetanus. A normal mouth opening is between 35 and 45 mm, with males typically having a slightly wider range. Mild trismus is classified as an opening of 20–30 mm, moderate as 10–20 mm, and severe as less than 10 mm. The word comes from the Greek trigmos or trismos, meaning a scream or grinding.
Differential diagnosis
Causes of trismus are traditionally divided into intra-articular (within the temporomandibular joint) and extra-articular (outside the joint). True bony ankylosis can result from trauma to the chin, infections, or prolonged immobilization following condylar fracture; treatment includes surgical procedures such as gap arthroplasty with interpositional materials. Fibrous ankylosis usually results from trauma and infection, and is treated with trismus appliances and physical therapy. Odontogenic causes include pulpal, periodontal, and pericoronal infections. Non-odontogenic causes include peritonsillar abscess, tetanus, meningitis, brain abscess, and parotid abscess. A hallmark of masticatory space infection is trismus; if unchecked, such infections can spread to facial spaces and lead to cervical cellulitis or mediastinitis. Dental trismus is a temporary condition usually lasting no more than two weeks, caused by injury to masticatory muscles, such as prolonged jaw opening or needle passage through muscle during lower jaw anesthesia. Oral surgery, such as extraction of lower molars, may cause trismus from inflammation or direct trauma to the TMJ. Barbed needles can cause post-injection trismus, paresthesia, and paresis. Fractures of the mandible or zygomatic arch, and accidental foreign bodies from trauma, are also causes.
More in Symptoms and Signs: Musculoskeletal System
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