Airway Scores — Mallampati, Cormack–Lehane & Composites

📊 Airway Scores — Values & Difficulty

What each measurement means, and the threshold that flags difficulty. Assess these at the bedside (see the Assessment tab).

Mallampati — original vs modified

Mallampati's original 1985 description had three classes; Samsoon & Young added a fourth in 1987, giving the modified Mallampati classification used today. Know both — the distinction is a classic viva question.

Modified Mallampati classes I to IV — Modified Mallampati classes I–IV (Samsoon & Young). Class IV — only the hard palate — was the addition to Mallampati's original three classes.
Jmarchn, Wikimedia Commons — CC BY-SA 3.0.

Class	Original Mallampati 1985 (3 classes)	Modified — Samsoon & Young 1987 (4 classes)
I	Soft palate, fauces, uvula & pillars	Soft palate, fauces, uvula & pillars
II	Soft palate, fauces & uvula	Soft palate, fauces & uvula (tip may be masked)
III	Soft palate only (uvula base)	Soft palate & base of uvula only
IV	— not described —	Hard palate only (added class)

Technique: patient sitting, mouth maximally open, tongue fully protruded, no phonation. Classes III–IV predict difficulty. Phonation or the supine position falsely improves the class.

Single bedside tests — thresholds

Test	Grades / values	Predicts difficulty when…
Modified Mallampati	I → IV (above)	III–IV
Inter-incisor gap	Normal >5 cm / 3 fingers	<3 cm (difficult DL); <2 cm (difficult LMA)
Thyromental distance	>6.5 cm reassuring	6–6.5 cm difficult but possible; <6 cm may be impossible
Sternomental distance	Sternal notch → chin, neck extended	<12.5 cm
Hyomental distance	Gr I >6 cm · II 4–6 cm · III <4 cm	Grade III (<4 cm)
Upper-lip-bite test	I: bite above vermilion · II: below · III: cannot reach	Class III
Mandibular protrusion (Prayer/ULBT)	A: lower teeth beyond upper · B: edge-to-edge · C: cannot	Class B / C
Neck / atlanto-occipital extension	Normal ≈35°	≥⅓–⅔ reduction of extension

Cormack–Lehane laryngoscopic grade — upgraded

The original 1984 grade (I–IV) has been refined by the Cook (2000) modification, which splits the ambiguous middle grades and groups the view by how you should act — easy → restricted → difficult.

Cormack–Lehane grades I to IV at laryngoscopy — Cormack–Lehane grades at laryngoscopy (I–IV).
User:Tubus, Wikimedia Commons — CC BY-SA 3.0.

Grade	Laryngoscopic view	Group / difficulty
1	Most of the glottis / full cords	Easy
2a	Partial view of the cords	Easy
2b	Arytenoids / posterior cords only	Restricted (intubation harder)
3a	Epiglottis only — liftable	Difficult (bougie may succeed)
3b	Epiglottis only — adherent to pharynx	Difficult
4	Neither epiglottis nor glottis	Very difficult

📐 Reporting the view — the modern additions

Grades 2b–4 define difficult laryngoscopy; 2b was carved out because it carries a much higher intubation-failure rate than 2a.
POGO (Percentage Of Glottic Opening) — a 0–100% continuous score of how much of the glottis you see; better than C–L for videolaryngoscopy and for describing improvement with a manoeuvre.
Always record the conditions: blade type/size, position, external laryngeal manipulation (BURP) and whether a bougie was used — a grade means little without them.

Composite / multivariable scores

Score	What it combines	Cut-off for difficulty
Wilson risk score	Weight, head-&-neck movement, jaw movement, receding mandible, buck teeth (each 0–2)	Total ≥2 (of 10) predicts difficult intubation
El-Ganzouri / Simplified Airway Risk Index (SARI)	Mouth opening, thyromental distance, Mallampati, neck movement, jaw protrusion, weight, history of difficult intubation (0–12)	≥4 suggests difficulty
LEMON score	1 point each: Look, 3-3-2 abnormal, Mallampati ≥3, Obstruction, Neck immobility	Higher score → higher risk (used in the ED)
Arné score	Pathology, prior difficulty, symptoms, Mallampati, TMD, mouth opening, neck movement	≥11 predicts difficulty

Bottom line: composites improve on any single test but none is perfect — always prepare for the airway you did not predict.