Superior Longitudinal Muscle Diseases

Diseases affecting the superior longitudinal muscle of the tongue encompass a broad spectrum of pathological conditions in which the intrinsic fibers immediately beneath the dorsal mucosa of the tongue are compromised. These disorders may be inflammatory (e.g., polymyositis, inclusion‐body myositis), congenital (e.g., muscular dystrophies), metabolic (e.g., Pompe disease), infectious (e.g., bacterial or viral myositis), neoplastic (e.g., rhabdomyosarcoma), traumatic (e.g., contusion or myositis ossificans), or neurogenic (e.g., hypoglossal nerve palsy). Clinically, they manifest as alterations in tongue shape, strength, mobility, and function, leading to dysarthria, dysphagia, pain, or tongue deformity. Early recognition is key, as many inflammatory and metabolic myopathies respond to timely immunosuppressive or enzyme‐replacement therapies, whereas neoplastic and traumatic lesions may require surgical intervention PubMedScience.gov.

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Anatomy of the Superior Longitudinal Muscle

Structure & Location

The superior longitudinal muscle is one of four intrinsic tongue muscles, forming a thin but centrally thick layer just beneath the mucosa on the dorsal surface of the tongue. It lies above the transverse and vertical intrinsic muscles and is confined entirely within the tongue, without extrinsic attachments NCBIRadiopaedia.

Origin

Fibers originate from the submucous fibrous layer close to the epiglottic region and from the median fibrous (lingual) septum, which partition the tongue into right and left halves Wikipedia.

Insertion

The muscle fibers run forward and fan out to insert into the lateral margins and tip (apex) of the tongue, immediately beneath the mucosal surface www.elsevier.com.

Blood Supply

Arterial blood is delivered primarily by branches of the lingual artery (a branch of the external carotid artery), specifically the dorsal lingual branches that supply the intrinsic musculature Kenhub.

Nerve Supply

Like all intrinsic tongue muscles (except palatoglossus), the superior longitudinal muscle is innervated by the hypoglossal nerve (cranial nerve XII), which provides motor fibers essential for fine shape changes WikipediaTeachMeAnatomy.

Functions

1. Shortening (Retraction): Contraction draws the tongue backward, shortening its length for bolus repositioning during swallowing NCBI.

2. Widening (Broadening): Shortening simultaneously increases the transverse diameter, aiding in mastication by flattening the tongue base NCBI.

3. Tip Elevation: Elevates the apex, critical for articulating alveolar phonemes (e.g., “t,” “d,” “n”) www.elsevier.com.

4. Lateral Margin Elevation: Raises the sides to create a trough for liquid boluses during swallowing NCBI.

5. Dorsiflexion (Curling Upward): Curls the tip and sides upward (dorsiflexion), forming a concave dorsum for directing food posteriorly www.elsevier.com.

6. Fine Motor Control: Works in concert with other intrinsic muscles to execute rapid shape changes necessary for nuanced speech and precise food manipulation Medscape.

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Types of Diseases

1. Inflammatory Myopathies (e.g., polymyositis, inclusion‐body myositis): Autoimmune inflammation causing fiber necrosis and weakness PubMedScience.gov.

2. Congenital Myopathies (e.g., Duchenne, Becker muscular dystrophies): Genetic defects in muscle proteins leading to progressive weakness and often macroglossia PubMed.

3. Metabolic Myopathies (e.g., Pompe disease): Enzyme deficiencies result in glycogen accumulation within muscle fibers, including tongue muscles PubMed.

4. Infectious Myositis: Bacterial (e.g., staphylococcal) or viral (e.g., influenza) invasion causing localized inflammation, pain, and swelling.

5. Neoplastic Lesions (e.g., rhabdomyosarcoma): Malignant proliferation of striated muscle precursors presenting as tongue masses.

6. Traumatic Injuries: Direct blunt or penetrating trauma leading to contusion, hemorrhage, or myositis ossificans in intrinsic fibers.

7. Neurogenic Disorders: Hypoglossal nerve injury (e.g., surgical trauma, tumor compression) causing denervation atrophy or paralysis.

8. Fibrosis and Scarring: Following chronic inflammation or radiation therapy, leading to reduced elasticity and mobility.

9. Amyloid and Sarcoid Infiltration: Deposition of abnormal proteins or granulomas within muscle tissue.

10. Spasm and Dystonia: Focal muscle hyperactivity (lingual dystonia) resulting in involuntary movements.

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Causes

1. Autoimmune Attack (e.g., polymyositis)

   • Immune‐mediated destruction of myofibers leads to muscle weakness and inflammation PubMed.

2. Protein Deficiency (e.g., dystrophin in Duchenne)

   • Genetic absence of key structural proteins causes fiber fragility and degeneration PubMed.

3. Enzyme Deficiency (e.g., acid α‐glucosidase in Pompe)

   • Accumulation of glycogen disrupts fiber architecture and function PubMed.

4. Viral Infection (e.g., Coxsackievirus)

   • Direct myocyte invasion triggers localized inflammation and muscle pain.

5. Bacterial Infection (e.g., Staphylococcus aureus)

   • Presents as focal abscess or diffuse myositis with swelling and redness.

6. Radiation Exposure

   • Fibrosis and vascular damage to muscle following head and neck radiotherapy.

7. Trauma (e.g., accidental bite, surgical injury)

   • Hemorrhage and contusion of intrinsic fibers impair mobility and cause pain.

8. Neoplastic Transformation (e.g., rhabdomyosarcoma)

   • Malignant cell proliferation within the muscle belly forms a mass lesion.

9. Hypoglossal Nerve Lesion

   • Denervation leads to atrophy, fasciculations, and tongue deviation.

10. Metabolic Toxins (e.g., alcohol, statins)

    • Myotoxic substances induce fiber necrosis and weakness.

11. Drug‐induced Myopathy (e.g., corticosteroids)

    • Prolonged steroid use can cause steroid myopathy with proximal weakness.

12. Endocrine Disorders (e.g., hypothyroidism)

    • Myxedema leads to mucopolysaccharide deposition and muscle stiffness.

13. Nutritional Deficiency (e.g., vitamin E)

    • Antioxidant lack exacerbates oxidative damage in muscle fibers.

14. Vascular Insufficiency (e.g., vasculitis)

    • Impaired blood flow causes ischemic fiber injury and pain.

15. Amyloidosis

    • Deposition of insoluble proteins disrupts normal muscle architecture.

16. Sarcoidosis

    • Noncaseating granulomas infiltrate muscle, causing weakness and inflammation PubMed.

17. Inclusion‐Body Myositis

    • Chronic inflammatory and degenerative changes with rimmed vacuoles Science.gov.

18. Granulomatous Myositis

    • Immune‐mediated granuloma formation within muscle bundles PubMed.

19. Parasitic Infection (e.g., Trichinella spiralis)

    • Larval invasion induces intense myositis and eosinophilic infiltration.

20. Ischemic Reperfusion (e.g., after surgery)

    • Reactive oxygen species generation leads to fiber apoptosis and dysfunction.

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Symptoms

1. Tongue Weakness

   • Difficulty in protruding, retracting, or moving the tongue side to side.

2. Dysarthria

   • Slurred or indistinct speech due to impaired tongue shape control.

3. Dysphagia

   • Difficulty swallowing liquids or solids, often with choking or coughing.

4. Pain or Tenderness

   • Localized aching within the tongue, exacerbated by movement.

5. Swelling (Macroglossia)

   • Enlargement of the tongue in congenital or infiltrative disorders PubMed.

6. Atrophy (Microglossia)

   • Thinning and shrinkage of the tongue in denervation or chronic myositis.

7. Fasciculations

   • Visible twitching of tongue fibers in hypoglossal nerve palsy.

8. Deviation on Protrusion

   • Tongue deviates toward the weaker side indicating unilateral denervation.

9. Ulceration or Mass

   • Presence of nodules or sores in neoplastic or traumatic lesions.

10. Numbness or Paresthesia

    • Altered sensation from concurrent neuropathy or inflammation.

11. Spasm or Dystonia

    • Involuntary contractions causing twisting or curling movements.

12. Taste Disturbance

    • Altered sweet, salty, sour, or bitter perception with mucosal disease.

13. Dryness or Fissuring

    • Cracks on the dorsum from chronic inflammation or nutritional deficiency.

14. Reduced Range of Motion

    • Inability to achieve full tongue elevation or lateral excursion.

15. Fatigue on Speaking

    • Tongue tires quickly during conversation or prolonged articulation.

16. Noisy Breathing

    • Obstruction of oropharyngeal airway with macroglossia in severe cases PubMed.

17. Biting During Mastication

    • Uncoordinated movements causing accidental biting of the tongue PubMed.

18. Voice Changes

    • Reduced resonance or altered timbre from poor tongue shaping.

19. Salivation Changes

    • Excessive drooling or dry mouth due to impaired tongue clearance.

20. Psychosocial Distress

    • Anxiety or embarrassment related to speech or cosmetic appearance.

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Diagnostic Tests

1. Clinical Examination

   • Inspection, palpation, and functional tests of tongue strength and mobility.

2. Speech Evaluation

   • Assessment by a speech‐language pathologist of articulation and intelligibility.

3. Electromyography (EMG)

   • Detects irritative or myopathic patterns in intrinsic muscle fibers.

4. Nerve Conduction Studies

   • Evaluates hypoglossal nerve integrity in suspected neuropathy.

5. Serum Muscle Enzymes

   • Elevated creatine kinase (CK), lactate dehydrogenase (LDH) in myositis.

6. Autoantibody Panels

   • ANA, anti–Jo‐1 for inflammatory myopathies such as polymyositis.

7. Erythrocyte Sedimentation Rate (ESR) & C‐Reactive Protein (CRP)

   • Markers of systemic inflammation in myositis or vasculitis.

8. MRI of the Tongue

   • High‐resolution imaging of muscle bulk, edema, or mass lesions.

9. Ultrasound

   • Real‐time evaluation of muscle architecture, echogenicity, and blood flow.

10. Muscle Biopsy

    • Histopathology to confirm myopathic changes, inclusion bodies, or granulomas PubMed.

11. Genetic Testing

    • Identification of dystrophin or other gene mutations in congenital myopathies.

12. Viral & Bacterial Cultures

    • Detection of infectious agents in aspirated fluid or tissue.

13. Serologic Titers

    • Antibody levels for viruses (e.g., Coxsackie) or parasites (e.g., Trichinella).

14. Electrodiagnostic Swallow Study

    • Videofluoroscopic assessment of bolus transit and tongue coordination.

15. Ultrasound Elastography

    • Measures tissue stiffness in fibrotic or neoplastic lesions.

16. Fine‐Needle Aspiration (FNA)

    • Cytology of palpable nodules to rule out malignancy.

17. CT Scan

    • Cross‐sectional anatomy for surgical planning or deep tissue evaluation.

18. Blood Glucose & Metabolic Panel

    • Screening for metabolic causes such as Pompe disease.

19. Endoscopic Examination

    • Visualization of pharyngeal clearance when dysphagia is prominent.

20. Autoimmune Inflammatory Markers

    • Complement levels, rheumatoid factor for associated connective‐tissue diseases.

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Non-Pharmacological Treatments

1. Speech‐Language Therapy: Exercises to improve articulation and swallowing coordination.

2. Myofunctional Therapy: Targeted exercises to strengthen intrinsic tongue muscles.

3. Physical Therapy: Range‐of‐motion and isometric/isotonic tongue exercises.

4. Occupational Therapy: Adaptive techniques for safe eating and speaking.

5. Heat Therapy: Warm compresses to reduce stiffness in fibrotic muscle.

6. Cold Therapy: Ice packs to alleviate acute inflammation in myositis.

7. Massage & Myofascial Release: Gentle manual mobilization to relieve spasm.

8. Acupuncture: Stimulation of tongue‐related acupoints for pain relief and mobility.

9. Dry Needling: Intramuscular trigger‐point release in focal areas of tension.

10. Transcutaneous Electrical Nerve Stimulation (TENS): Modulates pain signals.

11. Neuromuscular Electrical Stimulation (NMES): Enhances muscle contraction strength.

12. Low‐Level Laser Therapy (LLLT): Reduces inflammation and promotes healing.

13. Pulsed Electromagnetic Field Therapy: Stimulates cellular repair in injured muscle.

14. Biofeedback: Visual or auditory cues to optimize tongue movement patterns.

15. Yoga & Meditation: Stress reduction to decrease muscle tension and spasm.

16. Postural Training: Neck and head alignment to facilitate optimal tongue function.

17. Dietary Modification: Soft, well‐lubricated foods in dysphagia; avoid irritants in ulcerative lesions.

18. Hydration Optimization: Ensures mucosal lubrication and ease of swallowing.

19. Oral Orthoses: Custom appliances to support tongue position during recovery.

20. Swallowing Maneuvers: Chin‐tuck, supraglottic swallow to protect airway.

21. Chewing Gum Exercises: Enhances range of motion and proprioception.

22. Mirror Therapy: Visual feedback for precise movement correction.

23. Cognitive Behavioral Therapy (CBT): Addresses anxiety related to speech impairment.

24. Support Groups: Peer‐led encouragement and strategies for coping.

25. Heat/Cold Contrast Baths: Alternating temperatures to modulate blood flow.

26. Proprioceptive Training: Textured foods or tools to sharpen sensory feedback.

27. Manual Stretching: Gentle pulling of the tongue to maintain length and flexibility.

28. Respiratory‐Swallow Coordination: Breathing exercises to improve swallowing efficiency.

29. Digital Mobilization: Therapist‐guided finger exercises to stretch fibrotic areas.

30. Behavioral Modification: Habit reversal for tongue thrust or bruxism‐related spasm.

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Pharmacological Treatments

1. Nonsteroidal Anti‐Inflammatory Drugs (NSAIDs)

   • Ibuprofen or naproxen to reduce pain and inflammation in mild myositis.

2. Acetaminophen

   • Analgesic for pain relief without anti‐inflammatory action.

3. Systemic Corticosteroids (e.g., Prednisone)

   • First‐line immunosuppression in polymyositis; titrate to effect.

4. Methotrexate

   • Steroid‐sparing agent in chronic inflammatory myopathies.

5. Azathioprine

   • Alternative immunosuppressant for long‐term control.

6. Mycophenolate Mofetil

   • Used when other agents are contraindicated or ineffective.

7. Intravenous Immunoglobulin (IVIG)

   • Rapid immunomodulation in refractory myositis and inclusion‐body myositis PubMed.

8. Cyclophosphamide

   • Potent immunosuppressant for severe or life‐threatening cases.

9. Rituximab

   • Anti‐CD20 monoclonal antibody for antibody‐mediated myopathies.

10. Cyclosporine

    • Calcineurin inhibitor in resistant cases of polymyositis.

11. Botulinum Toxin Injection

    • Focal chemodenervation for lingual dystonia or spasm.

12. Muscle Relaxants (e.g., Baclofen, Tizanidine)

    • Reduce spasticity and improve comfort in dystonic conditions.

13. Tramadol

    • Weak opioid for moderate pain not controlled by NSAIDs.

14. Topical Lidocaine

    • Gel or patch for focal pain relief in ulcers or localized myositis.

15. Antibiotics (e.g., Cephalexin)

    • For bacterial abscess or cellulitis of tongue muscles.

16. Antivirals (e.g., Acyclovir)

    • In severe herpes‐related myositis.

17. Albendazole

    • Antiparasitic for Trichinella‐induced myositis.

18. Enzyme Replacement (e.g., Alglucosidase alfa)

    • For Pompe disease, improves muscle function and reduces glycogen load.

19. Coenzyme Q10

    • Mitochondrial support supplement in metabolic myopathies.

20. Vitamin E

    • Antioxidant therapy adjunct in selected neuromuscular disorders.

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Surgical Treatments

1. Partial Glossectomy

   • Resection of hypertrophic or neoplastic sections while preserving function.

2. Myectomy

   • Removal of a muscle portion to reduce spasm in focal dystonia.

3. Nerve Grafting

   • Hypoglossal nerve repair using autograft in traumatic denervation.

4. Nerve Decompression

   • Release of nerve entrapment to restore motor supply.

5. Excisional Biopsy

   • Diagnostic and therapeutic removal of small suspicious lesions.

6. Abscess Drainage

   • Incision and drainage for bacterial myositis with collection.

7. Laser Resection

   • Minimally invasive removal of small tumors with hemostasis.

8. Muscle Flap Reconstruction

   • Restoration of tongue bulk and mobility after extensive resection.

9. Tendon Transfer

   • Tendon graft from adjacent muscle to augment tongue elevation.

10. Cryoneurolysis

    • Freezing of peripheral nerve branches to manage spasm.

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Prevention Strategies

1. Genetic Counseling

   • For families with known congenital myopathies to guide reproductive choices.

2. Vaccination

   • Prevent viral infections (e.g., influenza) that can trigger myositis.

3. Protective Gear

   • Mouthguards in sports to reduce traumatic tongue injuries.

4. Optimal Glycemic Control

   • Minimize muscle complications in diabetic microangiopathy.

5. Hydration & Nutrition

   • Adequate protein, antioxidants, and fluids to support muscle health.

6. Smoking & Alcohol Cessation

   • Reduces toxin‐induced muscle damage.

7. Radiation Planning

   • Limit exposure to intrinsic tongue muscles during head & neck radiotherapy.

8. Early Treatment of Infections

   • Prompt antibiotics for oral infections to prevent myositis.

9. Regular Dental Check‐Ups

   • Prevent ulcerations and secondary infections of the tongue.

10. Ergonomic Speech Practices

    • Avoid overuse and strain through proper vocal techniques.

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When to See a Doctor

• Persistent Tongue Weakness lasting more than two weeks

• Progressive Speech or Swallowing Difficulties

• Unexplained Tongue Pain or Swelling

• Visible Mass or Nodules in the tongue

• Sudden Onset of Tongue Deviation or Fasciculations

• Unintentional Tongue Biting During Meals

• Fever with Tongue Redness or Ulceration

• Rapid Onset of Macroglossia Impairing Airway

• Resistance to Conservative Treatments (e.g., non‐pharmacologic measures)

• Systemic Symptoms (e.g., muscle aches elsewhere, rash, weight loss)

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Frequently Asked Questions

1. Can inflammation of the superior longitudinal muscle cause speech problems?
Yes. Inflammatory myositis can weaken intrinsic fibers, reducing the tongue’s ability to shape sounds, leading to slurred or distorted speech PubMed.

2. How is tongue myositis different from hypoglossal nerve palsy?
Myositis is a primary muscle inflammation; hypoglossal palsy is nerve‐related denervation. EMG and nerve conduction studies help distinguish them Science.gov.

3. Are there exercises to strengthen the superior longitudinal muscle?
Myofunctional exercises (e.g., tongue tip raises, lateral sweeps) under a speech therapist’s guidance can enhance strength and coordination.

4. What role does MRI play in diagnosis?
Tongue MRI visualizes muscle edema, atrophy, or masses, guiding biopsy or surgical planning.

5. Can congenital muscular dystrophy affect tongue function?
Yes. Disorders like Duchenne’s can cause macroglossia and weakness, impacting speech and swallowing PubMed.

6. Is corticosteroid therapy always required for tongue myositis?
Not always. Mild cases may respond to NSAIDs and physical therapy; severe or refractory cases benefit from corticosteroids.

7. How effective is IVIG in inflammatory tongue myositis?
IVIG often produces rapid improvement in weakness and pain, especially in refractory polymyositis PubMed.

8. What complications arise from untreated tongue tumors?
They can ulcerate, bleed, obstruct the airway, or metastasize if malignant.

9. Are there dietary modifications for tongue weakness?
Yes. Soft, pureed, or liquid diets reduce the effort required for chewing and swallowing.

10. Can botulinum toxin help with tongue spasm?
Yes. Targeted injections can relieve focal dystonia and improve comfort.

11. When is surgical intervention indicated?
For neoplastic masses, abscess drainage, or severe spastic deformities refractory to conservative care.

12. Does radiation therapy cause tongue fibrosis?
Exposure can damage microvasculature and lead to fibrotic scarring, reducing mobility.

13. How do I prevent drug‐induced myopathy?
Monitor muscle enzymes if on statins or corticosteroids, adjust dosages, and consider alternative medications.

14. Can physical therapy reverse muscle fibrosis?
While it improves flexibility and function, established fibrosis may require surgical release.

15. What supportive aids exist for severe dysphagia?
Feeding tubes (e.g., nasogastric or PEG) and adaptive utensils can maintain nutrition and quality of life.

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

Last Updated: April 22, 2025.