Which airway adjunct is sized by measuring from the mouth to the earlobe?

• A. Nasopharyngeal airway
• B. Endotracheal tube
• C. Oropharyngeal airway
• D. Laryngeal mask

Answer: (C)

Sizing an airway adjunct revolves around aligning its length with the anatomy you’re trying to support. The oropharyngeal airway is placed in the mouth and works by keeping the tongue from occluding the airway, so you want a length that puts the distal tip into the oropharynx behind the tongue without extending too far. A common way to choose this length is to measure from the mouth opening to a landmark such as the angle of the jaw or, in some protocols, to the earlobe. That measurement helps ensure the device is long enough to displace the tongue and hold the airway open, but not so long that it irritates or enters the pharynx improperly. If the airway is too short, the tongue can still block the passage; if it’s too long, it can cause discomfort, gagging, or tissue injury. For context, other airway devices are sized by different landmarks: nasopharyngeal airways by distance from the nostril to the earlobe, endotracheal tubes by internal diameter and length appropriate to the patient, and laryngeal masks by patient size or weight. The mouth-to-earlobe measurement specifically supports selecting the correct length for an oropharyngeal airway.