[Absolute strength of the muscles attached to the mandible]

In the course of an anatomical investigation of the muscles, securing movements of the mandible, performed on 10 human corpses, the muscle fibre length, volume and weight of each muscle has been estimated. Owing to the formula suggested by P. F. Leshaft (1880)--q = v/e, the physiological diameter of the muscles has been determined. Since the muscle with the diameter equal to 1 cm2 develops an absolute forse of 10 kg, the absolute muscle force value of the anterior group of muscles has been obtained for the first time (venter anterior musculi digastri--4.8 kg, musculus mylohyoideus--10.7 kg and musculus geniohyoideus--6.3 kg). The data on the absolute force of the posterior group of muscles has been verified (musculus masseter--24.2 kg, musculus temporalis--28 kg, musculus pterygoideus medialis--15.6 kg and musculus pterygoideus lateralis--15.5 kg). Analysing the interaction of forces of the muscles participating in the mandible movements, direction and value of displacements of the mandibular fragments have been explained and confirmed on some clinical examples. The data on the absolute force of the muscles studied can be used for investigating the displacement mechanism of the mandibular fragments after its resection and when its integrity is broken.