The masseter muscle, the principal muscle for chewing, is

Chapter 11, Problem 94GP

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The masseter muscle, the principal muscle for chewing, is one of the strongest muscles for its size in the human body. It originates on the lower edge of the zygomatic arch (cheekbone) and inserts in the angle of the mandible. Referring to the lower diagram in Figure 11–39, where \(d=7.60\ \mathrm {cm}\) and \(D=10.85\ \mathrm {cm}\), (a) find the torque produced about the axis of rotation by the masseter muscle. The force exerted by the masseter muscle is \(F_\mathrm M=455\ \mathrm {N}\). (b) Find the biting force, \(F_\mathrm {B}\), exerted on the mandible by the upper teeth. Find (c)  the horizontal and (d) the vertical component of the force \(F_\mathrm {J}\) exerted on the mandible at the joint where it attaches to the skull. Assume that the mandible is in static equilibrium, and that upward is the positive vertical direction.

Equation Transcription:

Text Transcription:

d=7.60 cm

D=10.85 cm

F_M=455 N

FB

F_J

F_B

F_M

26.0^o

F_J