Intrinsic Tongue Muscle Fibrosis

Tongue intrinsic muscles fibrosis is a condition characterized by the excessive build‑up of fibrous connective tissue within the intrinsic muscles of the tongue, leading to stiffness, reduced flexibility, and impaired tongue movement. Fibrosis occurs when the normal process of muscle repair is disrupted, resulting in an overproduction of collagen and other extracellular matrix components in place of healthy muscle fibers. This scarring makes the tongue less elastic and can significantly affect functions such as speaking, swallowing, chewing, and even breathing. Skeletal muscle fibrosis, including that affecting the tongue, “impairs muscle function, negatively affects muscle regeneration after injury, and increases muscle susceptibility to re‑injury” PubMed. In studies of the intrinsic tongue muscles, increased collagen deposition has been directly observed, confirming fibrosis at the cellular level dmp.umw.edu.pl.

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Anatomy

The intrinsic muscles of the tongue are four interwoven muscle groups confined entirely within the tongue. They change the shape of the tongue without attaching to bone. Their anatomy is as follows:

Structure and Location

• Superior longitudinal muscle: Lies just beneath the mucous membrane on the dorsum (top) of the tongue.

• Inferior longitudinal muscle: Runs along the underside (ventral surface) of the tongue.

• Transverse muscle: Fibers run side to side across the tongue, deep to the longitudinal muscles.

• Vertical muscle: Fibers run top to bottom, intersecting with transverse fibers in a lattice pattern.
  These interdigitated fibers allow precise changes in tongue shape and position Kenhub.

Origin and Insertion

• Superior longitudinal

  • Origin: Submucosal tissue near the epiglottis and the fibrous median septum.

  • Insertion: Apex and lateral margins of the tongue.

• Inferior longitudinal

  • Origin: Root of the tongue and median fibrous septum.

  • Insertion: Apex of the tongue.

• Transverse

  • Origin: Median fibrous septum.

  • Insertion: Submucosal connective tissue at the sides of the tongue.

• Vertical

  • Origin: Submucosal fibrous layer of the dorsum.

  • Insertion: Submucosal fibrous tissue of the ventral surface.

Blood Supply

All intrinsic muscles receive arterial blood primarily from the deep lingual artery, a branch of the lingual artery. Venous drainage occurs via the deep lingual vein.

Nerve Supply

Every intrinsic tongue muscle is innervated by the hypoglossal nerve (cranial nerve XII), which controls their precise, voluntary movements WikipediaRadiopaedia.

Functions

The intrinsic muscles work together to perform six key functions:

1. Elongation – Making the tongue longer.

2. Shortening – Retracting and narrowing the tongue.

3. Broadening – Widening the tongue.

4. Narrowing – Compressing the tongue side‑to‑side.

5. Flattening – Lowering the dorsum to flatten the tongue.

6. Arching – Elevating the sides to create a dome shape.

These shape changes enable complex tasks such as articulation in speech, precise manipulation of food during chewing, and efficient propulsion of food and liquids during swallowing.

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Types of Intrinsic Tongue Muscle Fibrosis

1. Congenital fibrosis

   • Present at birth due to developmental anomalies of muscle tissue formation.

2. Autoimmune‑related fibrosis

   • Occurs in conditions like systemic sclerosis where immune‑mediated inflammation leads to scarring.

3. Radiation‑induced fibrosis

   • Follows radiotherapy for head and neck cancers; profibrotic cytokines trigger collagen deposition PMC.

4. Drug‑induced fibrosis

   • Certain medications (e.g., bisphosphonates like zoledronic acid) can directly injure muscle, provoking fibrotic repair dmp.umw.edu.pl.

5. Post‑traumatic fibrosis

   • Develops after direct injury to the tongue, such as surgical trauma or lacerations.

6. Age‑related fibrosis

   • With aging, intrinsic muscles undergo fibrotic changes that may contribute to dysphagia in the elderly.

7. Idiopathic fibrosis

   • Scarring with no identifiable cause.

8. Metabolic disease–related fibrosis

   • Seen in diabetes or hypothyroidism due to chronic low‑grade inflammation.

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Causes

1. Aging – Natural decline in regenerative capacity leads to collagen replacement.

2. Radiation therapy – High‑dose radiation triggers TGF‑β1 release and collagen buildup PMC.

3. Bisphosphonate therapy – Drugs like zoledronic acid can induce muscle degeneration and fibrosis dmp.umw.edu.pl.

4. Systemic sclerosis – Autoimmune disorder causing widespread fibrosis, including the tongue.

5. Polymyositis/Dermatomyositis – Inflammatory myopathies that may progress to fibrotic scarring.

6. Muscular dystrophies – Genetic diseases where repeated injury leads to fibrosis PMC.

7. Trauma – Physical injury provoking scar tissue formation.

8. Infection – Chronic infections (e.g., tuberculosis, trichinosis) within muscle can fibrose.

9. Ischemia – Reduced blood flow (e.g., embolism) causing muscle injury and scarring.

10. Neuropathy – Denervation leading to atrophy and replacement by fibrous tissue.

11. Endocrine disorders – Hypothyroidism and diabetes mellitus can promote fibrosis.

12. Radiation‑associated dysphagia – Fibrosis of submental muscles indirectly affects intrinsic muscles PMC.

13. Chronic mechanical stress – Habitual tongue thrust or bruxism leading to microinjury.

14. Drug toxicity – Certain chemotherapeutics and antiretrovirals can injure muscle.

15. Occupational exposures – Chemical or thermal injuries in workplace accidents.

16. Vitamin deficiency – Lack of vitamins (D, C) impairs normal repair, favoring fibrosis.

17. Post‑surgical changes – Healing after glossectomy or other tongue surgeries can scar.

18. Connective tissue diseases – Lupus erythematosus, mixed connective tissue disease.

19. Chronic inflammation – Persistent inflammatory cytokine release drives fibroblast activation.

20. Idiopathic – Unknown factors leading to spontaneous fibrosis.

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 Symptoms

• Stiff or hard tongue

• Limited tongue movement

• Difficulty extending tongue

• Trouble retracting tongue

• Reduced tongue protrusion strength

• Slurred speech (dysarthria)

• Difficulty articulating certain sounds

• Chewing challenges

• Swallowing difficulty (dysphagia)

• Increased drooling

• Pain or discomfort when moving tongue

• Feeling of tightness under tongue

• Changes in taste sensation

• Oral hygiene problems

• Food trapping along tongue margins

• Weight loss from eating difficulty

• Coughing or choking during meals

• Aspiration of fluids

• Reduced tongue endurance (fatigue)

• Social embarrassment speaking or eating

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Diagnostic Tests

1. Physical examination – Palpation reveals hardness.

2. Speech evaluation – Assesses articulation deficits.

3. Videofluoroscopic swallow study – Visualizes tongue motion during swallowing.

4. Dynamic MRI – Shows muscle morphology and movement.

5. Ultrasound – Detects fibrotic bands and thickness.

6. Shear‑wave elastography – Measures tissue stiffness quantitatively.

7. CT scan – Highlights areas of dense fibrosis.

8. Electromyography (EMG) – Evaluates muscle electrical activity.

9. Nerve conduction studies – Rules out neuropathic causes.

10. Muscle biopsy – Confirms collagen deposition with trichrome staining dmp.umw.edu.pl.

11. Histology – Assesses fibroblast proliferation and extracellular matrix.

12. Immunohistochemistry – Detects markers like NF‑κB in fibrotic muscle dmp.umw.edu.pl.

13. Blood tests – Autoimmune panels (ANA, anti‑Scl‑70).

14. Inflammatory markers – ESR, CRP to gauge active inflammation.

15. Creatine kinase – Muscle injury indicator.

16. Tongue pressure measurement – Quantifies strength.

17. Swallowing manometry – Measures pressure flow dynamics.

18. Taste tests – Evaluates gustatory changes.

19. Saliva flow rate – Assesses secondary effects on salivation.

20. Genetic testing – When muscular dystrophy is suspected.

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Non‑Pharmacological Treatments

1. Passive tongue stretching

2. Active range‑of‑motion exercises

3. Isometric tongue strength training

4. Tongue lateralization exercises

5. Tongue push‑up against palate

6. Speech therapy

7. Swallowing therapy

8. Manual therapy (MT) – Soft‑tissue mobilization shown to reduce fibrosis dmp.umw.edu.pl.

9. Muscle energy techniques

10. Myofascial release

11. Massage

12. Low‑level laser therapy

13. Therapeutic ultrasound

14. Transcutaneous electrical nerve stimulation (TENS)

15. Neuromuscular electrical stimulation (NMES)

16. Acupuncture

17. Dry needling

18. Thermotherapy (heat packs)

19. Cryotherapy (cold packs)

20. Photobiomodulation

21. Hyperbaric oxygen therapy

22. Yoga‑based stretching

23. Resistance bands for tongue exercises

24. Biofeedback‑guided training

25. Postural control exercises

26. Chin‑tuck maneuvers

27. Diet modification (soft foods)

28. Hydration optimization

29. Mind‑body relaxation techniques

30. Manual cervical mobilization – Improving neck mobility to facilitate tongue function BioMed Central.

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Drugs

1. Pirfenidone – Anti‑fibrotic agent that inhibits TGF‑β pathways ScienceDirect.

2. Nintedanib – Tyrosine kinase inhibitor used in fibrotic diseases.

3. Prednisolone – Corticosteroid to reduce inflammation.

4. Methotrexate – Immunosuppressant for autoimmune‑related fibrosis.

5. Mycophenolate mofetil – Controls systemic sclerosis activity.

6. Azathioprine – Steroid‑sparing agent in inflammatory myopathies.

7. Cyclophosphamide – For severe, refractory autoimmune fibrosis.

8. Rituximab – B‑cell depleting therapy in scleroderma.

9. Losartan – Angiotensin II receptor blocker with anti‑fibrotic effects Institut de Myologie.

10. Captopril – ACE inhibitor shown to reduce collagen deposition.

11. Enalapril – Similar anti‑fibrotic ACE inhibitor.

12. Pentoxifylline – Improves microcirculation and reduces fibrosis.

13. Colchicine – Anti‑inflammatory, used in some fibrotic conditions.

14. Tranilast – Mast cell stabilizer with anti‑fibrotic properties.

15. Imatinib – Inhibits PDGF signaling involved in fibrosis.

16. N‑acetylcysteine – Antioxidant that may modulate fibrotic signaling.

17. Vitamin E – Antioxidant therapy in radiation fibrosis prevention.

18. Omega‑3 fatty acids – Anti‑inflammatory effects may reduce scarring.

19. Simvastatin – Statin with evidence of anti‑fibrotic action.

20. Metformin – AMPK activator shown to attenuate fibrosis.

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 Surgical Interventions

1. Z‑plasty scar revision – Reorients fiber direction to improve mobility.

2. CO₂ laser scar release – Precise excision of fibrotic bands.

3. Partial glossectomy – Removes severely fibrotic tissue segments.

4. Tongue flap reconstruction – Replaces resected area with vascularized tissue.

5. Microvascular free flap – E.g., radial forearm free flap for extensive defects.

6. Myotomy – Surgical cutting of fibrotic muscle fibers.

7. Submucosal tissue excision – Removes scar tissue beneath mucosa.

8. Buccinator musculomucosal flap – Local flap for coverage after release.

9. Frenulectomy – Releases tight frenulum contributing to restricted movement.

10. Laser‑assisted micro‑release – Minimally invasive fiber division.

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Preventive Measures

1. Intensity‑modulated radiotherapy (IMRT) – Targets tumors while sparing tongue tissue.

2. Prophylactic pentoxifylline + vitamin E during radiotherapy.

3. Early tongue and swallowing exercises starting before cancer treatment.

4. Hydration protocols to keep mucosa supple.

5. Dental clearance prior to bisphosphonate therapy.

6. Tight glycemic control in diabetic patients.

7. Smoking cessation to improve tissue healing.

8. Good oral hygiene to prevent chronic inflammation.

9. Minimize mechanical trauma during dental or surgical procedures.

10. Nutrient‑rich diet with antioxidants (vitamins C, E) to support repair.

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When to See a Doctor

• Tongue stiffness lasting longer than two weeks.

• Progressive difficulty in speaking or swallowing.

• Pain when moving the tongue.

• Weight loss due to eating problems.

• Drooling or inability to control saliva.

• Signs of infection (redness, swelling, fever).

• Suspected tumor or unexplained mass.

• Aspiration (choking on liquids).

• Speech changes affecting daily communication.

• Persistent numbness or altered sensation.

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Frequently Asked Questions

1. What exactly is tongue intrinsic muscles fibrosis?
   It’s scarring inside the tongue muscles that makes them stiff, reducing flexibility for talking and eating.

2. What symptoms should I watch for?
   Stiff tongue, trouble speaking clearly, difficulty chewing or swallowing, drooling, and tongue pain.

3. How is it diagnosed?
   By physical exam, imaging (MRI, ultrasound), swallowing studies, and sometimes a muscle biopsy.

4. Can it be reversed?
   Complete reversal is rare, but early treatment with therapy, medication, and sometimes surgery can improve function.

5. Are exercises helpful?
   Yes—tongue stretching and strengthening exercises guided by a speech‑language therapist are key non‑drug treatments.

6. What drugs treat it?
   Anti‑fibrotic agents (pirfenidone, nintedanib), immunosuppressants (methotrexate), and ACE inhibitors may help reduce scarring.

7. When is surgery needed?
   If fibrosis severely limits tongue movement or causes pain that doesn’t improve with therapy, surgical release or scar revision may be considered.

8. How long does treatment take?
   Non‑surgical therapy often lasts months; functional gains can continue for a year or more. Surgery recovery varies by procedure.

9. Can diet affect fibrosis?
   A soft, nutritious diet rich in antioxidants may support healing, but diet alone won’t reverse scarring.

10. Is tongue fibrosis painful?
    It can cause a burning or pulling sensation, especially when stretching or moving the tongue.

11. Can radiation cause this fibrosis?
    Yes—radiation for head and neck cancers is a well‑known cause of tongue muscle scarring.

12. Does systemic sclerosis affect the tongue?
    In scleroderma, immune‑driven fibrosis can involve the tongue, making it tight and stiff.

13. Is fibrotic tongue tissue at risk of cancer?
    Fibrosis itself isn’t cancerous, but any unusual mass warrants evaluation to rule out malignancy.

14. How common is tongue muscle fibrosis?
    It’s relatively rare; most cases are secondary to other conditions like radiation, drugs, or autoimmune disease.

15. How can I prevent it?
    Limit risk factors: use targeted radiotherapy, maintain good oral care, start exercises early, and follow medical guidance on medications.

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 22, 2025.

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