Core anatomical map
The airway is commonly divided into upper and lower segments.
- Upper airway: nose, oral cavity, pharynx, and larynx.
- Lower airway: trachea, bronchi, bronchioles, and alveolar pathways.
Clinically, this split matters because upper-airway processes (for example swelling, soft-tissue collapse, or supraglottic obstruction) often present and respond differently than lower-airway processes (for example bronchospasm).
Four bedside functions
- Patency: can air move through the airway without critical obstruction?
- Oxygenation: can oxygen reach blood across the lungs?
- Ventilation: can carbon dioxide be eliminated?
- Protection: can the airway limit aspiration and maintain reflex protection?
Loss of any one of these functions can destabilize a patient, even if the others are temporarily preserved.
Clinical anchors
- Stridor usually localizes concern to the upper airway.
- Wheeze usually localizes concern to lower-airway narrowing.
- A drop in oxygen saturation reflects oxygenation failure, but normal saturation does not exclude worsening ventilation.
- Worsening mental status during respiratory distress can indicate rising carbon dioxide or global hypoxia and should be treated as high risk.
Why this matters for FOAM
Airway FOAM is often scenario-based and rapid. Without this anatomy and physiology map, it is easy to memorize techniques without understanding indication, risk, and failure patterns.
For source links, see References and guidelines.