The percentage of dry weight distribution of the jaw muscles is described, and muscle growth is calculated by means of second degree homogeneous linear differential equations with constant coefficients. The components of the chewing muscles are calculated from the parallelogram of forces on the basis of their dry weights. Changes in the shape of the skull during postnatal development leads to an increase in the adductive components and a reduction of the protractive components. Changes in the reaction, medial tensile, lateral tensile and depressive components are minor.
Aging Animals