Mallampati Score Calculator

The Mallampati classification grades how much of the oropharynx remains visible when a seated patient opens the mouth fully and protrudes the tongue without phonating. The underlying premise is geometric: the tongue base occupies a fixed volume, and when that volume is large relative to the mandibular space available to receive it, the tongue obscures the pharyngeal structures on examination and equally obstructs the line of sight to the glottis during direct laryngoscopy. Class I shows soft palate, fauces, uvula and tonsillar pillars; Class IV shows the hard palate alone. The composite score here adds three further geometric predictors. Inter-incisor distance below 3 cm restricts laryngoscope blade insertion. Thyromental distance, measured from thyroid notch to chin tip with the neck extended, is normal above 6.5 cm or roughly three finger breadths; below 6 cm it signals an anterior larynx and a short mandibular space. Cervical mobility matters because neck extension is what aligns the oral, pharyngeal and laryngeal axes. Used alone the Mallampati score is a weak test. Reported sensitivity is roughly 60 to 70 percent and specificity 70 to 80 percent, with positive predictive values across published series ranging from about 13 to 50 percent, so most Class III and IV patients are still intubated without difficulty. The score also drifts within the same patient: phonation falsely improves it, while weight gain, advancing pregnancy, angioedema and oral tumours worsen it, which is why it should be repeated at each preoperative visit rather than copied forward.

Seshagiri Rao Mallampati, an anesthesiologist working at Massachusetts General Hospital, proposed the sign in a 1985 paper in the Canadian Anaesthetists Society Journal titled A clinical sign to predict difficult tracheal intubation, based on a prospective series of 210 patients. His original scheme contained only three classes. The idea was deliberately low technology: a bedside look that required no equipment and could be done in seconds, at a time when the alternative was radiographic measurement of mandibular and atlanto-occipital dimensions. In 1987 Samsoon and Young, reporting a retrospective study of failed intubations in the journal Anaesthesia, subdivided the original third class and created the four-class modified Mallampati scale now used almost universally. The scale gained traction because it mapped onto the laryngoscopic grading that Cormack and Lehane had described in 1984, giving clinicians a preoperative predictor of an intraoperative view. As validation studies exposed its limited predictive value in isolation, it was absorbed into multivariate assessments rather than discarded, appearing in the Wilson risk score, the LEMON assessment used in emergency medicine, and the STOP-BANG obstructive sleep apnea questionnaire. The American Society of Anesthesiologists incorporated it into its difficult airway practice guidelines, first issued in 1993 and revised in 2003, 2013 and 2022.