Zawawi et al reported a simple index of maximum mouth opening. The authors are from Boston and Tufts Universities in Boston.
Method: number of the patient's fingers that can be inserted into the patient's own open mouth between the upper and lower central incisors
The width of 3 fingers (at the distal IPJs) in an adult is about 47 mm.
The width of 4 fingers in an adult is about 58 mm.
Interpretation:
• Most healthy people can insert 3 fingers (from left or right hands) into the mouth.
• The total number of fingers that the patient can insert gives a rough idea about mouth opening.
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Specialty: Otolaryngology
