Lack's Tongue Depressor - ENT Instrument For MBBS Viva

Lack's tongue depressor is a very common instrument, you can find in ENT OPD. And nevertheless for an MBBS student of 3rd Professional (Part-1), it is a must know thing before you appear in the Practical examination.

Lack's Tongue Depressor, Ent Instrument

Lack's Tongue Depressor & its uses.

It is a metallic instrument with two blades, right angle to each other. One is slightly narrower than other. The wider blade is inserted into the mouth.

The tongue depressor has two curves, one just above the narrow end for a better grip.

Lack's tongue depressor has the following uses:
  • Diagnostic uses.
  • Therapeutic uses.

Lack's tongue depressor
Image showing lack's tongue depressor among other instruments of otorhinolaryngology (ENT).

Diagnostic uses.

1. This ENT Instrument used in the inspection of following structures: 
(Hint. Start from anterior structures of mouth)
  • Inner aspect of lip.
  • Gingivo-labial sulcus.
  • Gingivo-buccal sulcus.
  • Gums of teeth.
  • Anterior 2/3rd of the tongue.*
  • Buccal mucosa.
  • Floor of the mouth.
  • Corresponding hard and soft palate.
  • Retromolar trigone (hidden site).
  • Anterior tonsillar pillar.
  • Bilateral palatine tonsils.
  • Posterior tonsillar pillar.
  • Posterior pharyngeal wall.
2. Lack's tongue depressor is used for diagnosing of the chronic tonsillitis.

3. For assessment of nasal airway patency by Cold spatula test.

4. It is also used while posterior rhinoscopic examination.

Therapeutic uses of Lack's tongue depressor.

1. This instrument is used in any operations involving the oral cavity.

2. For taking biopsy of any oral cavity lesions.

3. Used while removing any foreign body.

4. Lack's tongue depressor is used to remove keratosis from tonsils.

5. To check adequacy of nasal pack.

Some frequently asked questions in the viva.

Here are some faqs and  high yield points that you should know about this instrument.

✅ Why is it used to inspect only anterior two-thirds of the tongue?

Posterior one-third of the tongue is not inspected using tongue depressor is due to the fact that it is supplied by Glossopharyngeal nerve which is more sensitive and leads to gagging. 

*You should know about the Gag reflex pathway.

✅ Why the two blades of tongue depressor is at right angle to each other?

It is because while inspection, the hand holding the instrument shouldn't obstruct the view of structure being examined.

✅ How chronic tonsillitis is diagnosed?

The three cardinal features of chronic tonsillitis are:
  1. On pressing the tonsils with lack's tongue depressor, cheesy white materials will come out.
  2. Flushing of the anterior tonsillar pillar.
  3. Palpable jugulodiagastric lymph nodes.

✅ What is the sterilization procedure for this instrument?

But in ENT OPD, warm water with soap or Cidex can be used to disinfect it.


Acute epiglottitis is a condition where use of Lack's tongue depressor is relatively contraindicated.

The above instruments have been photographed in the E.N.T. department of North Bengal Medical College & Hospital (NBMCH), Darjeeling, India. alert-success

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