Voice Production – Normal Mechanism

Larynx (Voice Box) की Anatomy

Basic Structure:

Larynx neck के front में, Adam’s apple के level पर स्थित है। यह cartilages, muscles, और mucosa का complex structure है।

Key Components:

1. Vocal Cords (Vocal Folds):

• Two bands of tissue stretched across larynx
• Length: Males ~17-25mm, Females ~12-17mm (males longer → deeper voice)
• Layers:
  • Epithelium (outer cover – stratified squamous)
  • Lamina Propria (3 layers – superficial, intermediate, deep)
  • Vocalis Muscle (innermost)
• Space between cords = Glottis

2. False Vocal Cords:

• Located above true cords
• Don’t vibrate normally
• Protective function

3. Cartilages:

• Thyroid Cartilage: Shield-shaped, forms Adam’s apple
• Cricoid Cartilage: Ring-shaped, below thyroid
• Arytenoid Cartilages: Pair, attached to posterior end of vocal cords – movement opens/closes glottis

4. Intrinsic Laryngeal Muscles:

• Control vocal cord movement
• Innervated by Recurrent Laryngeal Nerve (RLN) और Superior Laryngeal Nerve (SLN)

How Voice is Produced – Myoelastic-Aerodynamic Theory

Three Requirements for Voice:

1. Power Source (Respiration):

• Lungs provide air pressure
• Diaphragm और chest muscles control airflow
• Subglottic pressure builds up

2. Vibrator (Vocal Cords):

• Cords come together (adduction)
• Air pressure from lungs forces them apart
• Elastic recoil brings them back together
• Rapid vibration cycle (100-1000 times per second)
• Creates sound waves

3. Resonator (Vocal Tract):

• Pharynx, oral cavity, nasal cavity
• Shapes and amplifies sound
• Creates voice quality, timbre

Voice Characteristics:

• Pitch: Determined by cord length, tension, mass
  • Higher pitch: Tighter, thinner, longer cords
  • Males: ~120 Hz, Females: ~220 Hz
• Loudness: Determined by airflow, subglottic pressure
• Quality: Resonance characteristics

Types and Causes of Voice Problems

1. Acute Laryngitis

सबसे common cause of temporary hoarseness।

Causes:

• Viral Infection (Most Common 90%):
  • Rhinovirus, Adenovirus, Influenza
  • Part of upper respiratory infection
  • Self-limiting (7-10 days)
• Bacterial (Rare): Streptococcus, Moraxella
• Voice Overuse: Shouting, prolonged speaking

Symptoms:

• Hoarseness, voice change
• Throat discomfort, tickling sensation
• Dry cough
• Vocal fatigue
• Associated cold symptoms

Laryngoscopy Findings:

• Vocal cords red, swollen
• Increased mucus
• Incomplete glottic closure

2. Chronic Laryngitis

Hoarseness > 3 weeks, underlying cause needs identification।

Common Causes:

A. Laryngopharyngeal Reflux (LPR):

• Stomach acid reaching larynx
• Different from GERD (may not have heartburn)
• Symptoms:
  • Chronic throat clearing
  • Post-nasal drip sensation
  • Globus (lump feeling)
  • Worse in morning
  • Chronic cough
• Laryngoscopy: Posterior larynx inflammation, vocal cord edema

B. Smoking/Alcohol:

• Chronic irritation
• Edema, inflammation
• Increases cancer risk significantly

C. Chronic Sinusitis/Post-Nasal Drip:

• Mucus dripping on vocal cords
• Chronic throat clearing → trauma

D. Allergies:

• Laryngeal edema
• Mucus production

E. Environmental Irritants:

• Dust, pollution, chemicals
• Occupational exposure

3. Vocal Cord Lesions

A. Vocal Cord Nodules (“Singer’s Nodules”)

Bilateral, symmetrical, callus-like thickenings on vocal cords।

Cause:

• Chronic voice abuse/misuse
• Repeated trauma at junction of anterior 1/3 और middle 1/3 of cords
• High-risk: Teachers, singers, public speakers, children (shouting)

Symptoms:

• Gradual onset hoarseness
• Voice breaks, cracks
• Vocal fatigue – voice worsens by evening
• Difficulty with high notes (singers)
• Breathy quality

Laryngoscopy:

• Bilateral, symmetrical, white/translucent nodules
• At mid-point of membranous vocal cord
• Hourglass closure pattern

B. Vocal Cord Polyp

Usually unilateral, soft mass on vocal cord।

Causes:

• Acute phonotrauma (single episode of shouting/screaming)
• Smoking
• Chronic irritation

Symptoms:

• Hoarseness (sudden onset often)
• Diplophonia (double voice)
• Vocal breaks

Laryngoscopy:

• Unilateral (usually), pedunculated या sessile
• May be hemorrhagic (reddish)

C. Reinke’s Edema

• Diffuse swelling of superficial lamina propria
• Cause: Smoking (almost always), LPR
• Symptoms: Low-pitched voice (especially women)

D. Vocal Cord Cyst

• Fluid-filled sac in cord
• Congenital या acquired
• Similar symptoms to nodules/polyps

4. Neurological Causes

A. Vocal Cord Paralysis/Paresis

Recurrent Laryngeal Nerve (RLN) damage।

Causes:

• Surgical: Thyroid surgery (most common), cardiac surgery, lung surgery
• Tumors: Lung cancer, thyroid cancer, esophageal cancer
• Trauma: Neck injury, intubation injury
• Neurological: Stroke, multiple sclerosis
• Idiopathic: No cause found (viral neuritis suspected)

Types:

• Unilateral: One cord paralyzed
  • Hoarseness (breathy voice)
  • Vocal fatigue
  • Aspiration (choking on liquids)
  • Weak cough
• Bilateral: Both cords paralyzed
  • Severe breathing difficulty (emergency!)
  • Stridor (noisy breathing)
  • Voice may be relatively preserved
  • Needs urgent tracheostomy often

B. Spasmodic Dysphonia

• Neurological condition – involuntary spasms of vocal cords
• Voice breaks, strained-strangled quality
• Diagnosis: Specialist evaluation
• Treatment: Botox injections often helpful

5. Structural Problems

Vocal Cord Sulcus/Scar:

• Depression या scar on cord
• Congenital या post-surgical/trauma
• Stiff cord, poor vibration

Laryngeal Web:

• Membrane between cords
• Usually congenital
• Hoarseness from birth

6. Malignancy

Laryngeal Cancer:

⚠️ High-Risk Features:

• Hoarseness > 3 weeks (especially smokers)
• Progressive worsening
• Associated symptoms:
  • Throat pain
  • Referred ear pain
  • Difficulty swallowing
  • Hemoptysis (blood in sputum)
  • Weight loss
  • Neck lump
• Risk Factors: Smoking, alcohol (synergistic), HPV

Types:

• Glottic (70%): On vocal cords, early symptom (hoarseness), better prognosis
• Supraglottic (25%): Above cords, late symptoms
• Subglottic (5%): Below cords, rare, late presentation

Diagnosis at Prime ENT Center

1. Detailed History

• Onset & Duration: Sudden या gradual? How long?
• Voice Characteristics: Hoarse, breathy, strained, weak?
• Diurnal Variation: Worse morning (LPR) या evening (voice abuse)?
• Provoking Factors: Voice use, shouting, singing?
• Associated Symptoms: Pain, dysphagia, breathing difficulty?
• Voice Use Pattern: Professional voice user? Teacher, singer?
• Medical History: Recent surgery (thyroid), smoking, alcohol

2. Indirect Laryngoscopy

Using laryngeal mirror:

• Basic examination
• Vocal cord visualization
• Gross abnormalities

3. Videolaryngoscopy/Flexible Nasolaryngoscopy

Prime ENT Center में available – Gold Standard for voice assessment।

Procedure:

• Flexible scope passed through nose
• Video recording of larynx
• Assessment during phonation (speaking)
• High-definition image

Advantages:

• Better visualization
• Can see vocal cord mobility
• Document pathology
• Patient can see their own cords (educational)
• Track treatment response

Findings Assessed:

• Vocal cord color, surface, symmetry
• Mobility of both cords
• Glottic closure
• Lesions: Location, size, nature
• Surrounding structures

4. Stroboscopy (Advanced Assessment)

• Uses strobe light to see vibratory pattern
• Detects subtle mucosal wave abnormalities
• Important for professional voice users

5. Voice Analysis (Acoustic)

• Computer-based voice assessment
• Measures pitch, intensity, quality
• Objective documentation
• Treatment monitoring

6. Biopsy

• If suspicious lesion
• Microlaryngoscopy under GA
• Histopathological examination

Treatment at Prime ENT Center

Medical Management

1. Voice Rest

For Acute Laryngitis:

• Absolute voice rest (don’t whisper – worse than normal speaking!)
• Duration: 2-3 days for severe cases
• Then gradual return to normal use

2. Hydration

• Drink plenty of water (2-3 liters/day)
• Humidification (steam inhalation, humidifier)
• Avoid dehydrating substances (caffeine, alcohol)

3. LPR Treatment (If Diagnosed)

• Proton Pump Inhibitors (PPIs): As prescribed by doctor
• Lifestyle Modifications:
  • Elevate head while sleeping
  • No eating 3 hours before bed
  • Avoid trigger foods (spicy, acidic, fried)
  • Weight loss if obese
  • Quit smoking

4. Vocal Hygiene Education

• Proper voice use techniques
• Avoid shouting, throat clearing
• Use amplification when needed (teachers)
• Warm-up exercises for professional voice users

Voice Therapy

When Recommended:

• Vocal nodules (first-line treatment)
• Muscle tension dysphonia
• Post-surgery rehabilitation
• Professional voice users (prevention)

Therapy Components:

• Breathing Exercises: Proper support
• Relaxation Techniques: Reduce laryngeal tension
• Vocal Function Exercises: Strengthen cords
• Resonance Training: Improve voice quality
• Counseling: Voice hygiene, lifestyle changes

Surgical Treatment

1. Microlaryngeal Surgery (Phonomicrosurgery)

For: Vocal cord polyps, cysts, selected nodules, papillomas

Procedure:

• General anesthesia
• Suspension laryngoscopy – larynx exposed, held open
• Operating microscope for magnification
• Micro-instruments for precise removal
• Preserve normal cord tissue, maintain vocal fold layers
• Day care या overnight stay

Post-operative Care:

• Voice Rest: 7-10 days absolute
• Steam inhalation
• Hydration
• Avoid coughing, throat clearing
• Voice therapy follow-up
• Videolaryngoscopy at 3 weeks, 6 weeks

2. Vocal Cord Medialization

For: Unilateral vocal cord paralysis

Purpose: Move paralyzed cord to midline so opposite cord can meet it → better voice, prevent aspiration

Methods:

• Injection Medialization:
  • Office procedure या minor GA
  • Material injected into cord (hyaluronic acid, fat, collagen)
  • Temporary या semi-permanent
  • Good for recent paralysis (< 6 months)
• Medialization Thyroplasty:
  • Surgical procedure
  • Implant placed to push cord medially
  • Permanent solution
  • Usually done after 6-12 months if no recovery

Voice Care & Prevention

For Everyone:

• Hydration: Drink water throughout day
• Avoid Irritants: Smoke, excessive alcohol, pollution
• Healthy Lifestyle: Adequate sleep, stress management
• Treat Reflux: If present
• Don’t Ignore Persistent Hoarseness: > 2 weeks = ENT visit

For Professional Voice Users (Teachers, Singers, Speakers):

• Vocal Warm-up: Before prolonged use
• Use Amplification: Don’t strain voice
• Take Breaks: Voice rest periods
• Proper Technique: Voice training/lessons
• Avoid:
  • Shouting, screaming
  • Talking in noisy environments
  • Throat clearing (swallow instead)
  • Whispering (causes tension)
• Regular ENT Checkups: Annual videolaryngoscopy

Warning Signs – See ENT Immediately:

• Hoarseness > 2-3 weeks
• Complete voice loss
• Pain while speaking
• Difficulty breathing/swallowing
• Hemoptysis (blood in sputum)
• Neck lump
• Unexplained weight loss