(Originally presented by Dr Natalie Sim)

US can be used for identification of neck anatomy in patients with an anticipate difficult airway (including for LA topicalisation).

Potentially more accurate than traditional palpation/inspection techniques, without taking significantly longer.

Two Techniques

Horizontal – “TACA” (scan the following moving caudally)

  1. Thyroid cartilage (pyramidal)
  2. Air (interface between cricothyroid membrane and air in trachea)
  3. Cricoid cartilage (round)
  4. Air (move probe back up to cricothyroid membrane)

Transverse – “String of Pearls”

  • Takes longer than TACA but may provide extra information ie: overlying masses
  • Can be used in conjunction with TACA technique

(Includes how to mark the midpoint of the Cricothyroid membrane)

Further reading: 

BJA article : MS Kirstensen