The dimensions of the tongue in relation to its motility

To obtain basic information about the motility and dimensions of the tongue, the tongue volume was measured and the change in its length and location was noted while the tongue was undergoing protrusion, and then the relationships among those parameters were examined statistically. The tongue was measured at rest from the tip to a point 40 mm posterior corresponding to a plane connecting the lower permanent second molars. The subjects were 100 Japanese men and women. It was found that (1) maximum protrusion of the tongue is accomplished by two functions combined--a forward movement and a longitudinal stretching; the volume of the tongue was significantly correlated with its stretching. (2) The mean length of the tongue in the most protruded position was about 20% longer than its length in the resting position; it was stretched most in the segment from 1 to 2 cm posterior to its tip. (3) The mean tongue volume was 25.3 cm3 in men and 22.6 cm3 in women, a statistically significant sex difference; the volume was about 12% larger in men than in women. (4) There was no correlation between the tongue volume and the length of the most extraorally protruded tongue. The results suggested that the volume of the tongue can be estimated from the stretched length of the tongue in the most protruded position, if it is measured properly.