Wait, you thought we were done? This is a short post, following parts one, two and three. The above image attempts to describe lines of action for major jaw muscles and directions of force (arrows). Jaw protraction and retraction does not take into account probable shapes and extent of the rhamphotheca, which at the least might constrain how for anteriorly the mandible may protract, but also its ventral extent. Examining lines of action helps describe the angles of muscles to jaws for analyzing force for beam analysis. This does not take into account relative contribution of muscles to force production, in which case the red-pink labeled mPst will likely represent some of the weakest muscles. Typically, the major temporal muscles are preferred, and they may be assessed as a unit (mAME group), or in combination with the palatal muscles (mAME and mPT groups).
This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. It, and all of its files and contents -- unless otherwise noted -- are protected by this license.
License established 9/9/2012, while previously I was using a CC-BY-ND license instead.