What is Direct and Indirect Laryngoscopy ?


Direct and indirect laryngoscopy allows the visualization of the larynx through different ways. Both laryngoscopy methods are used for visualisation of the larynx for various purposes like airway management, diagnosis of pathology, tissue biopsy, surgery, etc.

What are direct laryngoscopy and indirect laryngoscopy?

Direct laryngoscopy :

Direct laryngoscopy is the visualisation of the larynx direct through the viewer's own eyes. The viewer can visualise the larynx, vocal cords, and adjacent structures directly.

Direct laryngoscopy procedure : 

  • Position: sniffing position - the most convenient position for direct laryngoscopy is the sniffing position
  • General or local Anaesthesia can be given according to the need
  • eye cover, dental protection, and the widest scope (different scopes to visualise different subsites of the endolarynx) are used.
  • The Head of the patient should reach the proximal edge of the table.
  • The "sniffer" or Boyce Jackson position provides the best visualization of the larynx.
  • Neck flexed on shoulders & head extended on neck
  • The scope is inserted to visualize the various parts of the larynx.

Indirect laryngoscopy :

 Indirect laryngoscopy suggests that the user has alternative ways besides a direct line of sight to see the larynx. These tools include the many video laryngoscopes (VL) available on the market as well as the flexible fiberoptic laryngoscopy utilized in hospitals by anesthesiologists to perform challenging intubations.

Indirect laryngoscopy procedure : 

  • The patient is seated opposite the examiner.
  • He should sit erect, with the head and chest leaning slightly in towards the examiner.
  • The patient is asked to protrude the tongue, a gauze is wrapped around it and the gauze-wrapped tongue is held by the examiner in between the thumb and the middle finger.
  • This gauze-wrapped tongue is held firmly to protect it against injury by lower incisors.
  • The index finger is used to keep the upper lip or the mustache out of the way.
  • The laryngeal mirror (size 4-6)  which has been warmed to match the body temperature and tested on the back of the hand is introduced into the mouth and held firmly against the uvula and the soft palate.
  • Light is focused on the laryngeal mirror and the patient is asked to breathe quietly.
  • To see the movements of vocal cords, the patient is asked to take a deep inspiration ( the vocal folds move away from each other), say "aa"(vocal folds move towards each other)and "Eee" (vocal folds move towards each other and tense).
  • Movements of both the cords are compared.

Direct laryngoscopy vs indirect laryngoscopy : 

There are many differences between direct and indirect laryngoscopy. Let's see some of the differences between direct and indirect laryngoscopy.                           

Indirect laryngoscopy

Direct laryngoscopy

Foreshortening of Anteroposterior diameter

No foreshortening

True and false vocal cords appear to be in contact with each other

True and false vocal cords are seen as separated by ventricles

Inverted mirror image

Direct visualisation

OPD procedure

Done in OT

Undersurface Is not seen

Some ideas of undersurface in gained

Ventricles not seen

Seen by pressing the false vocal cords


Conclusion :

 Direct and indirect laryngoscopy procedures are used to visualise the larynx. One needs to select the appropriate procedure according to the needs of the patient. For this, one should know the difference between direct and indirect laryngoscopy and the procedure of direct and indirect laryngoscopy. 


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