The vector of jaw muscle force as determined by computer-generated three dimensional simulation: a test of Greaves' model.
We present results from a detailed three-dimensional finite element analysis of the cranium and mandible of the Australian dingo (Canis lupus dingo) during a range of feeding activities and compare results with predictions based on two-dimensional methodology [Greaves, W.S., 2000. Location of the vector of jaw muscle force in mammals. Journal of Morphology 243, 293-299]. Greaves showed that the resultant muscle vector intersects the mandible line slightly posterior to the lower third molar (m3). Our work demonstrates that this is qualitatively correct, although the actual point is closer to the jaw joint. We show that it is theoretically possible for the biting side of the mandible to dislocate during unilateral biting; however, the bite point needs to be posterior to m3. Simulations show that reduced muscle activation on the non-biting side can considerably diminish the likelihood of dislocation with only a minor decrease in bite force during unilateral biting. By modulating muscle recruitment the animal may be able to maximise bite force whilst minimising the risk of dislocation.
School of Engineering, The University of Newcastle, NSW 2308, Australia. Philip.clausen@newcastle.edu.au
Philip
P
Clausen
Stephen
S
Wroe
Colin
C
McHenry
Karen
K
Moreno
Jason
J
Bourke
D000465:Algorithms; D001732:Bite Force; D003198:Computer Simulation; D006801:Humans; D008410:Masticatory Muscles / Q000502:physiology*; D008954:Models, Biological; D009119:Muscle Contraction / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical