A 6-month-old infant requires urgent endotracheal intubation. The anaesthetist notes that the narrowest portion of the upper airway differs between an infant and an adult. In an infant, the narrowest part of the laryngeal airway is:
- A The subglottis at the level of the cricoid ring ✓
- B The rima glottidis
- C The vestibule between the aryepiglottic folds
- D The interarytenoid region
Correct answer: A. The subglottis at the level of the cricoid ring
Explanation
In children, the cricoid cartilage forms a complete rigid ring and the loosely attached subglottic mucosa swells readily, making the subglottis the narrowest point until about 8 years of age. In adults the narrowest point is the rima glottidis between the vocal folds. This single fact explains why oedema of just 1 mm in a child's subglottis reduces the cross-sectional area drastically and why post-intubation subglottic stenosis is a paediatric problem.
Reference: Bailey and Love's Short Practice of Surgery, 27th ed.
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Written and medically reviewed by the StethoPrep medical team.