Airway ultrasound transverse views

This series of ultrasound images explores the airway in transverse section from the thyroid cartilage, through the cricothyroid membrane and on to the cricoid cartilage.

Upper thyroid cartilage – transverse view

The thyroid cartilage is triangular with an acute anterior angle in its cranial portion, rather like a steep sided volcano. This is more prominent in the male.


Mid thyroid cartilage – transverse view

As one proceeds caudally down the thyroid cartilage the anterior angle becomes less acute, like a less steeply sided volcano. In this image the false cords are seen.


Lower thyroid cartilage – transverse view
Cricothyroid membrane – transverse view

The air interface just deep to the cricothyroid membrane causes a bright linear reflection. The appearance of this has been likened to the caldera of a volcano.

Cricoid cartilage – transverse view

As one progresses further distally the rounded anterior part of the cricoid cartilage is seen. The appearance depends on the degree of age related calcification of this primarily cartilaginous structure.

Acoustic shadowing caused by calcification will completely obstruct the echogenic air interface. Whilst the cricoid remains cartilaginous and some ultrasound transmission occurs the air interface will be able to be seen, although less brightly than at the cricothyroid membrane.

Distal to the cricoid cartilage the tracheal rings and intervening spaces will be readily discernible.


The ultrasound appearance of the upper airway explained



An Emergency physician based in Perth, Western Australia. Professionally my passion lies in integrating advanced diagnostic and procedural ultrasound into clinical assessment and management of the undifferentiated patient. Sharing hard fought knowledge with innovative educational techniques to ensure knowledge translation and dissemination is my goal. Family, wild coastlines, native forests, and tinkering in the shed fills the rest of my contented time. | SonoCPDUltrasound library | Top 100 | @thesonocave |

One comment

  1. I cannot believe that my two passions have collided. I am a sonographer and an wannabe volcanologist! What a great example! Thank you!!!

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