Genioglossus Muscle Fibrosis

Genioglossus muscle fibrosis is a condition in which normal muscle fibers of the genioglossus—the large fan‑shaped muscle that forms most of the tongue’s body—are replaced by scar tissue. This scarring reduces the muscle’s elasticity and strength, impairing its ability to protrude, depress, and stabilize the tongue. As a result, patients may experience difficulty with breathing (e.g., obstructive sleep apnea), swallowing, and speech articulation .

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Anatomy of the Genioglossus Muscle

Structure & Location
The genioglossus is a broad, fan‑shaped muscle lying on the floor of the mouth. It forms the bulk of the tongue’s substance, spanning from the inner mandible forward into the tongue body .

Origin
All fibers arise from the superior mental spine (genial tubercle) on the inner midline of the mandible .

Insertion
The muscle fans upward and backward, inserting into:

• The dorsum of the tongue along a lingual aponeurosis

• The upper border of the hyoid bone .

Blood Supply
Arterial perfusion comes mainly from the lingual artery’s sublingual branches, with collateral flow from the facial artery’s submental branch .

Nerve Supply
Motor control is via the hypoglossal nerve (cranial nerve XII), which innervates all intrinsic and extrinsic tongue muscles except palatoglossus .

Functions

1. Protrusion: Pushes the tongue forward

2. Depression: Lowers the tongue body

3. Retraction & Flattening: Retracts and flattens the tongue

4. Unilateral Deviation: Side‑to‑side movement when one side contracts

5. Airway Patency: Maintains tongue position to keep the airway open during breathing

6. Swallowing & Speech: Shapes and stabilizes the tongue for safe swallowing and clear articulation .

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Types of Genioglossus Muscle Disorders

Genioglossus muscle disorders can be classified into six main types:

• Atrophy: Loss of muscle bulk

• Hypertrophy: Excessive muscle enlargement

• Spasm/Hypertonicity: Involuntary tightness or increased tone

• Paralysis: Complete loss of muscle function

• Fibrosis: Scar tissue replacing normal fibers, reducing elasticity

• Hypertonicity: Persistent high-tone state that limits movement .

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Causes

1. Hypoglossal nerve trauma during neck surgeries (e.g., carotid endarterectomy)

2. Medial medullary (brainstem) infarction affecting the hypoglossal nucleus Wikipedia

3. Skull base tumors (e.g., chordomas, metastases)

4. Nasopharyngeal carcinoma invading the hypoglossal canal

5. Paraganglioma (glomus tumor) in the carotid space

6. Carotid artery dissection compressing the nerve

7. Post‑carotid surgery nerve injury

8. Carotid space lymphadenopathy

9. Sublingual space abscess

10. Surgical trauma to the tongue or mandible

11. Radiation‑induced neuropathy after head & neck cancer therapy

12. Rheumatoid arthritis affecting the atlanto‑axial joint

13. Epstein‑Barr virus (mono) infection

14. Herpes simplex virus infection

15. COVID‑19–related peripheral neuropathy

16. Tuberculosis of the tongue base

17. Amyotrophic lateral sclerosis and other neurodegenerative diseases NCBI

18. Guillain‑Barré syndrome causing lower motor neuron damage Wikipedia

19. Diabetic neuropathy

20. Idiopathic hypoglossal neuropathy (unexplained) Physiopedia

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Symptoms

1. Tongue deviation toward the stronger side

2. Reduced tongue protrusion strength

3. Visible thinning (atrophy) on one side

4. Fasciculations (twitches) of tongue fibers

5. Slurred speech (dysarthria)

6. Difficulty swallowing (dysphagia)

7. Excessive drooling

8. Chewing difficulties

9. Speech clarity issues (trouble with consonants)

10. Snoring from partial airway collapse

11. Obstructive sleep apnea events

12. Daytime fatigue and sleepiness

13. Night‑time choking/gasping

14. Bad breath from pooled secretions

15. Altered taste if sensory fibers affected

16. Tongue pain or tenderness

17. Muscle cramping during eating

18. Difficulty clearing saliva

19. Aspiration pneumonia risk

20. Muffled or nasal‑tone voice changes

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Diagnostic Tests

1. Cranial nerve XII neurological exam

2. Tongue protrusion observation

3. Electromyography (EMG) of tongue

4. Hypoglossal nerve conduction study

5. MRI of brainstem/skull base

6. CT of neck and skull base

7. Ultrasound of tongue muscle

8. Polysomnography (sleep study)

9. Fiberoptic laryngoscopy

10. Videofluoroscopic swallow study (VFSS)

11. Fiberoptic endoscopic evaluation of swallowing (FEES)

12. Serum creatine kinase (CK) and infectious markers

13. Autoimmune antibody panels

14. Tongue muscle biopsy for myositis

15. Lumbar puncture (CSF analysis)

16. Drug‑induced sleep endoscopy

17. Nocturnal pulse oximetry

18. Speech‑language pathology assessment

19. Genetic testing for hereditary neuropathies

20. Electrocardiogram (ECG) if vascular stroke is suspected

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Non‑Pharmacological Treatments

1. Continuous positive airway pressure (CPAP)

2. Hypoglossal nerve stimulation implant (Inspire)

3. Mandibular advancement device

4. Oral appliance therapy

5. Weight loss & exercise

6. Positional therapy (avoid supine sleep)

7. Tongue‑strengthening exercises

8. Myofunctional therapy (targeted drills)

9. Speech therapy

10. Swallowing therapy with SLP

11. Respiratory muscle training

12. Biofeedback control training

13. Neuromuscular electrical stimulation

14. Cervical posture correction

15. Yoga & Pilates for neck/core

16. Breathing (pranayama) exercises

17. Sleep hygiene optimization

18. Dietary modifications (soft diet)

19. Hydration management

20. Reflux control (head elevation)

21. Therapeutic ultrasound to soften scar tissue

22. Photobiomodulation (low‑level laser therapy)

23. Osteopathic manual therapy of the lingual complex

24. Daytime neuromuscular EMST devices (e.g., eXciteOSA®)

25. Transcutaneous electrical nerve stimulation (TENS) of CN XII

26. Shaker exercise for suprahyoid and tongue elevation

27. Masako maneuver (tongue‑hold swallow)

28. Effortful swallow exercise

29. Supraglottic swallow exercise

30. Super‑supraglottic swallow exercise

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Drugs

1. Botulinum toxin A (chemodenervation for spasm)

2. Baclofen (GABA B agonist for spasm)

3. Tizanidine (α₂‑agonist spasmolytic)

4. Diazepam (benzodiazepine muscle relaxant)

5. Prednisone (oral steroid for inflammatory myositis)

6. Methotrexate (immunosuppressant for myositis)

7. Pirfenidone (anti‑fibrotic agent)

8. Losartan (ARB with anti‑fibrotic effects)

9. Nintedanib (tyrosine kinase inhibitor)

10. Halofuginone (collagen I synthesis inhibitor)

11. Formoterol (β₂‑agonist with anti‑fibrotic action)

12. Givinostat (Duvyzat) (HDAC inhibitor in DMD)

13. Pamrevlumab (FG‑3019) (anti‑CTGF antibody)

14. Garetosmab (REGN‑2477) (anti‑activin A mab)

15. Asengeprast (FT011) (GPR68 inhibitor)

16. Collagenase nanocapsules (enzyme delivery for scar breakdown)

17. Taldefgrobep alfa (anti‑myostatin adnectin)

18. Bimagrumab (anti‑activin II receptor antibody)

19. Apitegromab (SRK‑015) (anti‑promyostatin mab)

20. Trevogrumab (myostatin inhibitor under study)

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Surgical Options

1. Genioglossus advancement (GGA) for OSA

2. Hypoglossal nerve stimulation implant

3. Uvulopalatopharyngoplasty (UPPP)

4. Maxillomandibular advancement (MMA)

5. Partial glossectomy (tongue reduction)

6. Microvascular decompression of CN XII

7. Nerve grafting for hypoglossal palsy

8. Hyoid suspension procedures

9. Tumor resection along the nerve pathway

10. Selective neural denervation

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Preventive Measures

1. Use nerve‑safe techniques in neck surgery

2. Control hypertension & diabetes to prevent stroke

3. Avoid excessive alcohol/sedatives before sleep

4. Maintain healthy weight to reduce OSA risk

5. Practice good sleep hygiene

6. Perform daily tongue exercises

7. Treat reflux promptly

8. Stay up to date on vaccinations (e.g., flu)

9. Wear protective gear in contact sports

10. Monitor side effects during cancer/radiation therapy

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When to See a Doctor

Seek evaluation if you notice persistent tongue weakness or deviation, slurred speech, difficulty chewing/swallowing, new‑onset loud snoring with gasping, unexplained tongue pain or twitching, or sudden changes in tongue size/movement .

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Frequently Asked Questions

1. What is the genioglossus muscle?
   The main fan‑shaped muscle in the tongue that controls protrusion, depression, and airway support .

2. Why does my tongue deviate to one side?
   Weakness or paralysis of one genioglossus causes deviation toward the strong side .

3. Can tongue exercises help?
   Yes—targeted myofunctional drills often improve tone and function .

4. What causes tongue atrophy?
   Chronic nerve injury (e.g., stroke, tumor) .

5. Is an enlarged tongue dangerous?
   Macroglossia can obstruct breathing, impair speech, and cause dental issues .

6. How is sleep apnea linked?
   Weak genioglossus tone lets the tongue collapse backward at night .

7. Are there injections to reduce spasm?
   Botulinum toxin injections can safely relieve persistent spasms .

8. What tests confirm nerve injury?
   EMG, nerve conduction studies, and MRI help pinpoint damage .

9. When is surgery needed?
   For severe OSA not helped by CPAP, structural tumors, or significant macroglossia .

10. Can drugs reverse atrophy?
    Medications treat inflammation/autoimmunity but cannot regrow fibers .

11. Is speech therapy helpful?
    Absolutely—SLPs train safe swallowing and clear articulation .

12. What lifestyle changes help?
    Weight management, sleep position, and avoiding sedatives improve symptoms .

13. How long to recover from nerve injury?
    Weeks for mild cases; deficits may be permanent if the nerve is severed .

14. Can children get these disorders?
    Yes—congenital macroglossia, birth trauma, or genetic myopathies can affect kids .

15. Where can I find support?
    Sleep apnea groups, speech clinics, and cranial nerve palsy foundations offer resources .

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

Last Updated: April 18, 2025.