It is time for a cognitive upgrade
The airway is not something you find.
It is something you navigate.
The screen gives you a two-dimensional image. The Two-Curve Theory gives you the three-dimensional map needed to act on it.
Entered from the physical poster? Begin with this short film. The online and in-person paths meet here.
Beyond anatomic landmarks
Identification is not navigation.
The tongue, epiglottis, and vocal cords tell you where you are. The Two-Curve Theory connects those landmarks to the curved path the blade and tube must travel.
One airway · two connected curves
See the image. Predict the route.
The airway is not one straight axis. It is a connected passage with two dominant curves that meet near the laryngeal vestibule.
Oral cavity → oropharynx
The path wrapping around the tongue—the curve a hyperangulated blade is designed to follow.
Where the curves change
The transition near the base of the epiglottis where the airway changes direction.
Pharynx → glottis → trachea
The downstream route the tube must navigate after the cords come into view.
A strong view is information. The mental model turns that information into purposeful movement.
Geometry changes the strategy
Let the path tell the tool what to do.
This is the bridge—not the entire technique lesson. The chapters ahead will teach how the blade, stylet, and tube manage each curve.
Approximate a line of sight
Positioning and tissue displacement reduce the primary curve.
Follow the primary curve
The camera looks around the bend without complete alignment.
Respect the secondary curve
The tube still needs a deliberate shape and downstream trajectory.
Go deeper only when it supports your practice
Origins and hands-on translation.
Open either extension—or continue directly to the Bottom Line and Poster 412.
Skip to the Bottom Line ↓01Where the Two-Curve Theory came from＋
Greenland and colleagues proposed the model after studying sagittal airway configuration across different head and neck positions. They described a primary oropharyngeal curve and a secondary pharyngo-glotto-tracheal curve, with an inflection point where they meet.
Its practical value is the shift from isolated landmarks and abstract axes toward relationships, curvature, and the way a chosen device changes the path.
Read the foundational study ↗02Practice seeing and feeling the curves＋
See the curves
Trace both curves on the visual model before picking up a device.
Feel the route
Rehearse how a blade and tube move through the tabletop model.
Compare tools
Notice how different introducers respond to the same path.
Carry this forward
Landmarks tell you where you are.
Geometry tells you where to go next.
References and educational-use noteOpen ＋
- Greenland KB, Edwards MJ, Hutton NJ, Challis VJ, Irwin MG, Sleigh JW. Changes in airway configuration with different head and neck positions using magnetic resonance imaging of normal airways: a new concept with possible clinical applications. Br J Anaesth. 2010;105(5):683–690. PMID: 20846964.
- This educational page supports clinician learning and does not replace local protocols, patient-specific assessment, or clinical judgment.
