Mirror and flexible laryngoscopy

What it is

The larynx cannot be seen through the open mouth, so it is examined indirectly. Mirror (indirect) laryngoscopy uses a warmed mirror placed at the back of the mouth and a head light; it is quick but limited by the gag reflex. Flexible laryngoscopy passes a thin endoscope through the nose after a topical decongestant and anaesthetic and shows the nose, nasopharynx, tongue base, epiglottis, piriform sinuses and vocal folds while the patient breathes and speaks. It is the standard office test for persistent hoarseness, throat symptoms in smokers, suspected vocal fold paralysis and airway assessment.

Findings and interpretation

• One immobile fold with a weak, breathy voice suggests vocal fold paralysis; causes include neck or chest surgery, lung or thyroid cancer and skull base tumours.
• Paralysis of both folds is rare but usually causes serious breathing problems.
• A white plaque (leukoplakia) on a fold in a smoker needs biopsy to exclude dysplasia or cancer.
• Any lesion found on a fold needs further evaluation, usually operative endoscopy and biopsy.
• Supraglottic symptoms (difficulty swallowing, airway obstruction, ear pain, neck mass) need direct laryngoscopy without delay.
• The mirror view of the subglottis and trachea is limited; bronchoscopy is needed if disease is suspected there.

How it is done

1. Check the indication and contraindications (suspected epiglottitis, unstable airway) and explain the procedure.
2. Flexible: apply a topical decongestant and anaesthetic to the more open nostril and wait several minutes.
3. Pass the scope along the floor of the nose beside the inferior turbinate into the nasopharynx; note adenoids and eustachian tube openings.
4. Ask the patient to breathe through the nose so the soft palate drops, then flex the tip down past the palate.
5. Inspect the tongue base, valleculae, epiglottis, piriform sinuses, arytenoids and the false and true vocal folds.
6. Ask for «eee» and for quiet breathing: the folds should close in the midline and open fully and symmetrically.
7. Mirror method: warm the mirror, hold the tongue forward with gauze, rest the back of the mirror against the uvula and ask for «eee».
8. Afterwards, nothing to eat or drink for at least 20 minutes while the throat is numb.

Mirror versus flexible laryngoscopy

Common mistakes

• Prescribing months of antibiotics or reflux medicines for hoarseness without examining the larynx.
• Attempting office laryngoscopy in a patient with drooling, stridor and suspected epiglottitis.
• Forgetting to ask about thyroid or chest surgery in a patient with a new breathy voice.

Next step / Initial management

• Hoarseness for more than 2 to 3 weeks, or earlier in smokers: refer to ENT for laryngoscopy.
• Hoarseness with difficulty swallowing, ear pain, a neck mass or breathing difficulty: urgent referral without delay; stridor at rest is an emergency.
• Suspected epiglottitis: do not examine the throat with instruments; arrange airway management where a difficult airway can be handled.
• Lesion or white plaque on a fold: specialist operative endoscopy and biopsy.
• Vocal fold paralysis of unknown cause: the specialist looks for a cause along the course of the nerve (skull base, neck, chest).

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Educational content; it does not replace a medical assessment and is not a clinical instruction. For a real case, follow current guidelines and specialist advice.

Sources: How To Do Flexible Laryngoscopy (MSD Manual Professional Edition, 2025); How To Do Mirror Laryngoscopy (MSD Manual Professional Edition, 2025); Laryngeal Cancer (MSD Manual Professional Edition, 2024); Vocal Fold Paralysis (NIDCD, National Institutes of Health, 2017).

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Representative model, for educational purposes only.