The larynx also known as the voice box is the triangle shaped tubular structure in neck. Laryngoscopy is medical procedure to visualize the larynx and structures around the larynx like epiglottis and vocal cords. The larynx can be visualized by
- Direct method: using laryngoscope, laryngeal endoscope, nasopharyngolaryngoscopy (NPL).
- Indirect method: using indirect laryngoscopic mirror.
Indirect laryngoscopy is the procedure for the visualization of larynx by indirect method. It uses indirect laryngoscopic mirror to visualize the larynx.
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Instruments required:
- Indirect laryngoscopic mirror
- Bulls lamp
- Head mirror
- Gauze piece
- Alcohol/ spirit lamp or warm water
- Local anesthetic solution
Set up
Patient is seated on chair opposite to the examiner lying face to face. At that position, the legs of the examiner and the patients should not crossed, touched or placed in between. The sitting level of examiner is same or little high than the level of patient. The patient is asked to sit erect with head and chest leaning forward. This position is referred as sniffing position by some authors.
Procedure
Greet the patient
You can say good morning/ afternoon/ evening according to the time at examination. You may greet patient according to their religion like saying as-salam walekum to muslim patient. It is important as it is first step to build good rapport.
Introduce yourself and explain about procedure
You have to introduce yourself to patient so that patient trusts you. Explain in brief about the procedure, importance of examination in diagnosis and the common complications.
Get consent and start the examination procedure
Patient is asked to gargle with local anesthetic solution and spit. Meanwhile the examiner sets up the instruments and lightening. Turn on the Bulls lamp and use head mirror to focus light parallel to your field of vision.
Patient is asked to open his/ her mouth and to protrude the tongue. With the help of gauze piece grasp the tongue with middle finger and thumb. The index finger is used to hold upper lip of patient.
Warm the Indirect laryngoscopic mirror on mirror side on alcohol lamp or warm water. Check the temperature of mirror so that it won’t hurt the patient. It can be done by checking the temperature of mirror on your dorsal surface of palm. If you feel it is perfect you can further conform by placing mirror on dorsal surface of palm of the patient and asking if this temperature is not too warm for him/ her. Warming the mirror is very important as it prevents from fogging of the mirror.
The indirect laryngoscopic mirror is then introduced into the oral cavity and is introduced beyond the uvula and soft palate. The uvula is gently lifted for better view of the larynx.
Ask the patient to take deep breaths from mouth to see movements of vocal cords. You can ask patient to produce sounds like ‘aa’ or ‘ee’ to see abduction or adduction of vocal cords.
If fogging appears on mirror, restart the warming process and again follow the procedure till you do the complete assessment of larynx.
Structures seen on indirect laryngoscopy
- Base of tongue
- Lingual tonsils
- Valleculae
- Medial glossoepiglottic fold
- Lateral glossoepiglottic fold
- Both pyriform fossa
- Posterior cricoid region
- Posterior part of laryngopharynx
- Epiglottis
- Aryepiglottic folds
- Arytenoids
- Cuniform
- Curniculate
- True cords
- Anterior commissure
- Posterior commissure
- Subglottis
- Upper rings of trachea
Assessment of vocal cords
The vocal cord movements, color, surfaces, edges are examined for any pathologies on vocal cords
- Color: normally color is pearly white.
- Movements: any restrictions for movement are noted.
- Surfaces: for ulcerations.
- Edges: for irregularities.
Structures seen on direct laryngoscopy but not on indirect laryngoscopy
- Apex of pyriform fossa.
- Ventricles.
- Laryngeal surface of epiglottis.
- Subglottic region.
