Friends, you must have heard about a medical term called “LOCKED JAW”. It generally refers to difficulty in or inability to fully open the mouth due to stiffness or spasm of the jaw muscles. The medical term for this condition is called ‘Trismus’. It is not a disease but a symptom or an underlying condition affecting the jaw muscles, joints, or surrounding structures.
A normal mouth opening is about 35-55 mm (roughly 2-3 finger breaths). Anything significantly less may indicate trismus.
Common Causes of Locked Jaw
1 Temporomandibular Joint (TMJ) Disorders– Dysfunction of the joint connecting the jaw to the skull
Causes:
- Disc displacement
- Arthritis (osteoarthritis or rheumatoid arthritis)
- Joint inflammation
Symptoms
- Clicking or popping sounds, Jaw deviation, ad Pain near the ear.
2 Muscle Spasm (Most Common) – Overuse or strain of the jaw muscle-
- Triggers: Teeth grinding, Stress and anxiety, and Excessive chewing (gum, hard foods).
- Often temporary but painful
3 Dental Causes
- Impacted wisdom tooth
- Dental infections (abscess)
- Recent dental procedures (e.g., injections, extractions)
- Poor oral hygiene leads to inflammation
4 Trauma or Injury
- Jaw fracture or dislocation
- Sift tissue injury
- Post-surgical stiffness
5 Infections
- Tetanus (lockjaw)-rare but serious, causes severe muscle rigidity
- Oral or throat infections like Pericoronitis (gum infection around wisdom teeth)
- Tonsillitis and deep neck infections
6 Oral Cancer or Tumours
- Tumours affecting jaw muscles or nerves- this is progressive and often associated with weight loss, persistent ulcers and difficulty in swallowing.
7 Radiation Therapy
- Especially in head and neck cancer treatment
- Causes fibrosis (stiffening) of jaw muscles
8 Neurological Conditions
- Stroke
- Parkinson’s disease
- Nerve damage affecting jaw control
9 Medications
Certain drugs can cause muscle stiffness or dystonia
Symptoms Associated with Locked Jaw
- Difficulty opening the mouth
- Pain while chewing or speaking
- Jaw stiffness
- Headache or ear pain
- Swelling in the face or jaw
- Clicking or grinding sounds
- Fever (if infection is present)
Diagnosis
A doctor or dentist may evaluate:
- Medical or dental history
- Physical exam (jaw movement, pain points)
- Imaging- X-ray, CT scan, and MRI (for soft tissue/TMJ issues)
Treatment Options,
1 Home Remedies (Mild Cases)
- Warm compress to relax muscles
- Gentle jaw stretching exercises
- Soft diet (avoid hard or chewy foods)
- Avoid extreme jaw movements (wide yawning, chewing gum)
2 Medications
- Pain relievers
- Muscle relaxants
- Anti-inflammatory drugs
- Antibiotics (if infection present)
3 Physical Therapy
- Jaw exercises
- Ultrasound therapy
- Massage techniques
4 Dental Treatment
- Treat infections or abscesses, removal of impacted teeth, bite correction
5 TMJ-Specific treatments
- Mouth guards (for teeth grinding), Splints, Steroid injections
6 Advanced Treatments
- Botox injections for severe muscle spasm
- Surgery (rare) for joint repair, tumour removal
- Treatment of underlying systemic disease
When to Seek Immediate Medical Help
- Jaw locked completely (cannot open at all)
- Severe pain or swelling
- Fever with jaw stiffness
- Difficulty in breathing or swallowing
- Symptoms after a wound (possible tetanus)
Prevention Tips
- Maintain good oral hygiene
- Avoid excessive chewing habits
- Manage stress ( to reduce clenching/grinding)
- Use protective gear during sports
- Regular dental check-ups
- Timely treatment of infections
In the end, a locked jaw is usually temporary and treatable, often caused by muscle strain or TMJ issues. However, it can sometimes signal serious conditions like infection or tumours, so persistent or severe symptoms should not be ignored.
Anil Malik
Mumbai, India
14th May 2026