Book contents
- The Mammalian Jaw
- The Mammalian Jaw
- Copyright page
- Dedication
- Contents
- Preface
- Acknowledgments
- Introduction
- 1 The jaw viewed as a two-dimensional lever
- 2 The jaw viewed as a three-dimensional lever
- 3 Vector inclination and joint location
- 4 Skull torsion and the postorbital bar
- General summary
- References
- Index
2 - The jaw viewed as a three-dimensional lever
Published online by Cambridge University Press: 05 August 2012
- The Mammalian Jaw
- The Mammalian Jaw
- Copyright page
- Dedication
- Contents
- Preface
- Acknowledgments
- Introduction
- 1 The jaw viewed as a two-dimensional lever
- 2 The jaw viewed as a three-dimensional lever
- 3 Vector inclination and joint location
- 4 Skull torsion and the postorbital bar
- General summary
- References
- Index
Summary
In a two-dimensional jaw mechanism, joint stability requires only that the resultant muscle force be located behind the most posterior tooth. A stable three-dimensional jaw mechanism requires that the resultant force of the jaw muscles be located within a triangle formed by the two jaw joints and the bite point. One consequence of this relationship is that the muscle force cannot be maximized at the rear of the tooth row and bite forces in this region are not as high as might be expected.
The anteroposterior location of the muscle force is 30% of jaw length from the jaw joint. The mediolateral location of the tooth row seems to be essentially the same in many mammals after taking the length and width of the jaw into account.
- Type
- Chapter
- Information
- The Mammalian JawA Mechanical Analysis, pp. 26 - 51Publisher: Cambridge University PressPrint publication year: 2012