Mastication Muscle Injuries

A mastication muscle injury refers to damage or strain affecting the muscles responsible for chewing, primarily the masseter, temporalis, medial pterygoid, and lateral pterygoid muscles. These injuries can range from mild overstretching (strains) to partial or complete tears, contusions (bruises), inflammation (myositis), or even avulsion (where the muscle pulls away from its attachment). Such injuries often cause pain, swelling, limited jaw movement, and difficulty chewing. Evidence shows timely diagnosis and management can reduce complications and restore full function.

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Anatomy of the Mastication Muscles

Structure & Location

The mastication muscles form a powerful group on each side of the head and face.

• Masseter: A thick rectangular muscle at the cheek’s side, covering the jaw’s angle.

• Temporalis: A broad, fan-shaped muscle on the temples, stretching from the temporal bone to the coronoid process of the mandible.

• Medial Pterygoid: A quadrilateral muscle inside the jaw, near the throat, deep to the mandible’s angle.

• Lateral Pterygoid: A two-headed muscle (superior and inferior bellies) located deep within the face, above the medial pterygoid.

Origin & Insertion

• Masseter

  • Origin: Zygomatic arch (cheekbone).

  • Insertion: Lateral surface of the mandibular ramus and angle.

• Temporalis

  • Origin: Temporal fossa (side of skull).

  • Insertion: Coronoid process of the mandible.

• Medial Pterygoid

  • Origin: Pterygoid plate of the sphenoid bone and maxillary tuberosity.

  • Insertion: Medial surface of the mandibular ramus.

• Lateral Pterygoid

  • Origin:

    • Superior head: Infratemporal surface of the greater wing of the sphenoid.

    • Inferior head: Lateral surface of the lateral pterygoid plate.

  • Insertion:

    • Superior head: Articular disc and capsule of the temporomandibular joint (TMJ).

    • Inferior head: Pterygoid fovea on the condylar neck of the mandible.

Blood Supply

• Masseter & Medial Pterygoid: Branches of the maxillary artery (masseteric artery for masseter; pterygoid branches for pterygoids).

• Temporalis: Deep temporal arteries from the maxillary artery.

• Lateral Pterygoid: Pterygoid branches of the maxillary artery.

Nerve Supply

All mastication muscles receive motor innervation from the mandibular division (V₃) of the trigeminal nerve (cranial nerve V):

• Masseteric nerve (masseter)

• Deep temporal nerves (temporalis)

• Medial and lateral pterygoid nerves (pterygoids)

Key Functions

1. Elevation of the Mandible: Closing the jaw to bite or chew (masseter, medial pterygoid, temporalis).

2. Depression of the Mandible: Opening the jaw, assisted by lateral pterygoid.

3. Protrusion of the Mandible: Pushing the jaw forward (lateral pterygoid and medial pterygoid).

4. Retrusion of the Mandible: Pulling the jaw backward (posterior fibers of temporalis).

5. Lateral Excursion: Side-to-side movement for grinding (alternating contraction of pterygoids and masseters).

6. Stabilization of the TMJ: Keeping the jaw joint aligned during chewing.

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Types of Mastication Muscle Injuries

1. Muscle Strain: Overstretching or minor tearing of muscle fibers.

2. Muscle Tear (Partial or Complete): More severe fiber disruption causing pain and weakness.

3. Contusion (Bruise): Blunt trauma leading to blood leakage within the muscle.

4. Avulsion: Muscle pulling away from its bony attachment.

5. Myositis: Inflammation of the muscle, often due to infection or repetitive stress.

6. Myofascial Pain Syndrome: Chronic trigger points within the muscle causing referred pain.

7. Muscle Spasm: Involuntary contraction or cramp.

8. Overuse Injury: Repetitive chewing or bruxism leading to fatigue and microtears.

9. Traumatic Laceration: Open wound cutting through muscle tissue.

10. Ischemic Injury: Reduced blood flow causing muscle fiber death.

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Causes of Mastication Muscle Injury

1. Direct Trauma: Blow to the jaw or face (sports injury, fall).

2. Bruxism (Teeth Grinding): Chronic clenching leading to overuse.

3. Malocclusion: Misaligned teeth causing uneven muscle strain.

4. Excessive Yawning: Overstretching temporalis or pterygoid.

5. Dental Procedures: Prolonged mouth opening during treatment.

6. Whiplash: Sudden neck movement affecting jaw muscles.

7. Stress: Emotional tension increasing clenching or muscle tension.

8. Repetitive Chewing: Habitual chewing of gum or hard foods.

9. Infection: Bacterial or viral myositis.

10. Autoimmune Diseases: Rheumatoid arthritis affecting TMJ and muscles.

11. Nutritional Deficiency: Low magnesium or vitamin D causing cramps.

12. Tumors: Mass effect compressing muscle tissue.

13. Radiation Therapy: Fibrosis and muscle damage post-radiation.

14. Congenital Disorders: Genetic muscle weakness conditions.

15. Neurological Disorders: Trigeminal neuralgia causing dyskinesia.

16. Medication Side Effects: Statins causing muscle pain.

17. Systemic Lupus Erythematosus: Inflammatory muscle involvement.

18. Sarcoidosis: Granulomatous inflammation of muscles.

19. Metabolic Myopathies: Inborn errors of muscle energy metabolism.

20. Dehydration: Reduced perfusion and muscle cramping.

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Symptoms of Mastication Muscle Injury

1. Jaw Pain: Localized or radiating to ear, temple, or neck.

2. Swelling: Visible puffiness over cheeks or temples.

3. Tenderness: Pain on palpation of the affected muscle.

4. Limited Mouth Opening (Trismus): Difficulty opening wide.

5. Jaw Deviation: Chin shifts toward injured side when opening.

6. Muscle Weakness: Reduced bite or chewing strength.

7. Stiffness: Difficulty moving jaw, especially in the morning.

8. Muscle Spasms: Sudden, involuntary contractions.

9. Bruising: Skin discoloration overlying contusion.

10. Clicking or Popping: Sounds at the TMJ during movement.

11. Headaches: Tension headaches from muscle strain.

12. Earache (Otalgia): Referred pain to the ear.

13. Facial Asymmetry: Swelling or muscle atrophy causing uneven look.

14. Difficulty Chewing: Pain or fatigue during eating.

15. Fever: With infectious myositis.

16. Fatigue: Muscle tiredness after use.

17. Crepitus: Grinding sensation in the joint.

18. Numbness or Tingling: If nerve involvement occurs.

19. Salivary Changes: Drooling if mouth cannot close properly.

20. Weight Loss: From reduced eating due to pain.

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Diagnostic Tests

1. Physical Examination: Palpation, range of motion, strength testing.

2. Dental/Oral Examination: Inspect teeth and bite alignment.

3. Panoramic X-ray: Views teeth, jawbone, and joint.

4. Cone Beam CT (CBCT): Detailed 3D imaging of bones and muscles.

5. Magnetic Resonance Imaging (MRI): Soft tissue contrast for muscle edema or tears.

6. Ultrasound: Real-time muscle visualization and guidance for injections.

7. Electromyography (EMG): Assesses muscle electrical activity.

8. Nerve Conduction Study: Evaluates trigeminal nerve function.

9. Blood Tests: CBC, ESR, CRP for inflammation or infection.

10. Rheumatoid Factor & ANA: Autoimmune screening.

11. Serum Creatine Kinase (CK): Elevated in muscle injury.

12. Occlusal Analysis: Bite force measurement.

13. Thermography: Detects heat patterns over inflamed muscles.

14. Diagnostic Local Anesthetic Injection: Confirms muscle versus joint pain.

15. Jaw Tracking Devices: Measure movement patterns.

16. 3D Facial Scanning: Records asymmetry.

17. Trigger Point Mapping: Identifies myofascial pain spots.

18. Biopsy: Rarely, for suspected muscle disease.

19. CT Arthrography: Joint space detail with contrast.

20. Fluoroscopy: Dynamic imaging of jaw motion.

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Non-Pharmacological Treatments

1. Rest: Avoid chewing hard foods.

2. Cold Pack: 10–15 minutes to reduce acute swelling.

3. Heat Therapy: Warm compresses to relax muscles.

4. Gentle Stretching: Slow jaw opening exercises.

5. Massage: Myofascial release of trigger points.

6. Physical Therapy: Supervised jaw exercises.

7. Ultrasound Therapy: Deep heat to promote healing.

8. Transcutaneous Electrical Nerve Stimulation (TENS): Pain relief.

9. Biofeedback: Teaches muscle relaxation.

10. Occlusal Splints/Night Guards: Prevent bruxism.

11. Soft Diet: Yogurt, soup, mashed foods.

12. Dietary Modification: Avoid gum, nuts, tough meats.

13. Posture Correction: Neck alignment to reduce muscle tension.

14. Stress Management: Meditation, breathing exercises.

15. Acupuncture: Pain modulation in trigger areas.

16. Dry Needling: Trigger point release.

17. Chiropractic Adjustment: Cervical spine alignment.

18. Osteopathic Manipulation: Soft tissue and joint mobilization.

19. Jaw Resting Position: Lips together, teeth apart.

20. Ergonomic Changes: Desk and screen height for posture.

21. Low-Level Laser Therapy: Speeds tissue repair.

22. Extracorporeal Shockwave Therapy (ESWT): Breaks scar tissue.

23. Mind-Body Techniques: Yoga, tai chi.

24. Cold Laser (Photobiomodulation): Cellular healing.

25. Heat Packs with Ultrasound Gel: Improved heat conduction.

26. Trigger Point Injections (saline): Diagnostic and therapeutic.

27. Manual Lymphatic Drainage: Reduce edema.

28. Cognitive Behavioral Therapy (CBT): Address pain behaviors.

29. Ergonomic Chewing Aids: Chew slowly with smaller bites.

30. Jaw Neuromuscular Re­education: Relearn balanced chewing patterns.

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Drugs for Mastication Muscle Injury

1. Ibuprofen (NSAID) – Reduces pain & inflammation.

2. Naproxen (NSAID) – Long-acting anti-inflammatory.

3. Diclofenac (Topical gel) – Local inflammation control.

4. Acetaminophen (Paracetamol) – Analgesic relief.

5. Aspirin – Analgesic & mild anti-inflammatory.

6. Cyclobenzaprine – Skeletal muscle relaxant.

7. Methocarbamol – Central muscle relaxant.

8. Prednisone – Systemic corticosteroid for severe inflammation.

9. Methylprednisolone – Short-term high-dose steroid.

10. Lidocaine Patch – Local anesthetic pain block.

11. Capsaicin Cream – Desensitizes pain receptors.

12. Gabapentin – Neuropathic pain modulator.

13. Pregabalin – Reduces nerve pain and muscle tension.

14. Amitriptyline – Low-dose tricyclic for chronic pain.

15. Duloxetine – SNRI for musculoskeletal pain.

16. Clonazepam – Controls muscle spasms.

17. Botulinum Toxin Type A (Botox) – Reduces muscle hyperactivity.

18. Amoxicillin – If bacterial infection present.

19. Clindamycin – For penicillin-allergic patients.

20. Tramadol – Weak opioid for severe pain.

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Surgical Interventions

1. Arthrocentesis: Flushing TMJ to relieve pressure.

2. Arthroscopy: Minimally invasive joint repair.

3. Open TMJ Surgery: Disc repositioning or removal.

4. Coronoidectomy: Removing coronoid process to improve opening.

5. Muscle Debridement: Removing scarred or necrotic tissue.

6. Tendon Repair: Re-anchoring avulsed muscle.

7. TMJ Replacement: Prosthetic joint in severe degeneration.

8. Orthognathic Surgery: Correcting jaw alignment.

9. Neurectomy: Cutting a nerve branch for refractory pain.

10. Bone Grafting: For structural defects affecting muscle function.

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Prevention Strategies

1. Use Mouthguards: In contact sports to prevent trauma.

2. Avoid Hard Foods: Popcorn kernels, ice, unpopped grains.

3. Manage Stress: Meditation, relaxation reduce clenching.

4. Correct Bite Alignment: Orthodontic treatment.

5. Practice Good Posture: Neck and head alignment.

6. Warm-Up Exercises: Gentle jaw stretches before heavy use.

7. Limit Gum Chewing: Prevent overuse.

8. Stay Hydrated: Prevent cramps.

9. Regular Dental Check-ups: Catch malocclusion early.

10. Adequate Nutrition: Magnesium, calcium, vitamin D.

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When to See a Doctor

Seek professional care if you experience:

• Severe or escalating pain that does not respond to rest or over-the-counter pain relief.

• Marked swelling or bruising around the jaw or face.

• Significant limitation in opening your mouth (less than 25 mm).

• Fever or systemic symptoms, suggesting infection.

• Persistent clicking/locking of the jaw.

• Numbness or weakness in facial muscles.
  Early evaluation by a dentist, oral surgeon, or ENT specialist ensures prompt diagnosis and prevents long-term complications.

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Frequently Asked Questions (FAQs)

1. What causes a muscle strain in my jaw?
   Overstretching from excessive chewing, teeth grinding, or sudden mouth opening can tear muscle fibers.

2. How long does jaw muscle injury take to heal?
   Mild strains may recover in 1–2 weeks; severe tears or surgeries can require several months of rehabilitation.

3. Can video gaming cause mastication muscle pain?
   Yes, holding your jaw tensely while concentrating can lead to muscle fatigue and discomfort.

4. Is a “popping” sound in my jaw concerning?
   Occasional popping can be harmless, but frequent or painful pops deserve a medical evaluation.

5. Are warm compresses or cold packs better?
   Use cold packs for the first 48 hours to reduce swelling, then switch to warm compresses to relax muscles.

6. Can stress worsen my jaw pain?
   Absolutely—stress increases clenching and muscle tension, worsening pain.

7. Is massage safe for TMJ muscle injuries?
   Gentle, professional myofascial massage can relieve trigger points and improve flexibility.

8. When is surgery necessary?
   Surgery is reserved for cases unresponsive to conservative care, such as severe avulsion or joint degeneration.

9. Will physical therapy help?
   Yes, guided exercises and modalities like ultrasound accelerate recovery and restore function.

10. Can I prevent jaw injury during sports?
    Yes—wear a fitted mouthguard and avoid high-risk impacts.

11. Are Botox injections safe for jaw muscle pain?
    When administered by a qualified professional, Botox can safely reduce muscle hyperactivity for several months.

12. What role does nutrition play?
    Adequate hydration and nutrients like magnesium and vitamin D help prevent cramps and support healing.

13. Is jaw clicking always a problem?
    Not always—but if clicking is painful or limits movement, seek evaluation.

14. Can poor posture affect my jaw muscles?
    Yes, forward head posture strains neck and jaw muscles, contributing to injury.

15. How can I sleep better if I grind my teeth?
    Use a night guard, practice relaxation before bed, and address stressors to reduce bruxism.

Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical  history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.

The article is written by Team Rxharun and reviewed by the Rx Editorial Board Members

Last Updated: April 24, 2025.

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