Thyromental distance

Thyromental distance is a clinical measurement used in anesthesiology to predict the difficulty of endotracheal intubation. It is the distance from the thyroid notch to the lower border of the mandible with the head fully extended.

Measurement

The thyromental distance is measured with the patient's head fully extended and the mouth closed. The distance from the thyroid notch to the lower border of the mandible is measured in a straight line. A thyromental distance of less than 6 cm is associated with difficult intubation.

Clinical significance

The thyromental distance is used as a preoperative assessment tool to predict the difficulty of endotracheal intubation. It is one of several measurements used to assess the airway, along with the Mallampati score, sternomental distance, and mouth opening. A short thyromental distance is associated with difficult intubation and a higher risk of complications during anesthesia.

See also

• Mallampati score
• Sternomental distance
• Mouth opening
• Endotracheal intubation