VISUALISING MUSCLE ANATOMY USING THREE-DIMENSIONAL COMPUTER MODELS - AN EXAMPLE USING THE HEAD AND NECK MUSCLES OF SPHENODON

We demonstrate how the computer-based technique of multi-body dynamics analysis (MDA) can be used to create schematic, but informative three-dimensional (3D) representations of complex muscle anatomy. As an example we provide an overview of the head and neck muscles present in Sphenodon (Diapsida: Lepidosauria: Rhynchocephalia). First a computer model based on micro-computed tomography datasets provides a detailed and anatomically correct three-dimensional (3D) framework to work from. Secondly, muscles are represented by groups of cylinders that can be colour coded as desired. This allows muscle positions, attachment areas, and 3D orientation to be visualised clearly. This method has advantages over imaging techniques such as two-dimensional drawings and permits the form and function of the muscles to be understood in a way that is not always possible with more classical visualisation techniques. Copyright: Palaeontological Association December 2009.

[1]  L. Witmer.  2 The Extant Phylogenetic Bracket and the importance of reconstructing soft tissues in fossils , 2007 .

[2]  L. Witmer,et al.  New Insights Into the Brain, Braincase, and Ear Region of Tyrannosaurs (Dinosauria, Theropoda), with Implications for Sensory Organization and Behavior , 2009, Anatomical record.

[3]  Takanobu Tsuihiji,et al.  Homologies of the transversospinalis muscles in the anterior presacral region of Sauria (crown Diapsida) , 2005, Journal of morphology.

[4]  Mark D Sutton,et al.  Tomographic techniques for the study of exceptionally preserved fossils , 2008, Proceedings of the Royal Society B: Biological Sciences.

[5]  Herbert R. Barghusen.  The adductor jaw musculature of Dimetrodon (Reptilia, Pelycosauria) , 1973 .

[6]  E. C. Olson.  JAW MECHANISMS: RHIPIDISTIANS, AMPHIBIANS, REPTILES , 1961 .

[7]  C. Holliday.  New Insights Into Dinosaur Jaw Muscle Anatomy , 2009, Anatomical record.

[8]  M W Vannier,et al.  Noninvasive Three-Dimensional Computer Imaging of Matrix-Filled Fossil Skulls by High-Resolution Computed Tomography , 1984, Science.

[9]  M. Vannier,et al.  Endocranial features of Australopithecus africanus revealed by 2- and 3-D computed tomography. , 1990, Science.

[10]  G. Throckmorton.  Action of the pterygoideus muscle during feeding in the lizard Uromastix aegyptius (Agamidae) , 1978, The Anatomical record.

[11]  Susan E. Evans,et al.  Predicting muscle activation patterns from motion and anatomy: modelling the skull of Sphenodon (Diapsida: Rhynchocephalia) , 2010, Journal of The Royal Society Interface.

[12]  Chris Coletta,et al.  Techniques for Modeling Muscle‐induced Forces in Finite Element Models of Skeletal Structures , 2007, Anatomical record.

[13]  L. Witmer,et al.  The Paranasal Air Sinuses of Predatory and Armored Dinosaurs (Archosauria: Theropoda and Ankylosauria) and Their Contribution to Cephalic Structure , 2008, Anatomical record.

[14]  A. Russell,et al.  Functional variation of neck muscles and their relation to feeding style in Tyrannosauridae and other large theropod dinosaurs , 2007, Anatomical record.

[15]  Neil Curtis,et al.  Predicting Skull Loading: Applying Multibody Dynamics Analysis to a Macaque Skull , 2008, Anatomical record.

[16]  Xiaocong Wu.  Functional morphology of the temporal region in the Rhynchocephalia , 2003 .

[17]  Michael J Fagan,et al.  Assessment of the role of sutures in a lizard skull: a computer modelling study , 2009, Proceedings of the Royal Society B: Biological Sciences.

[18]  Takanobu Tsuihiji,et al.  Homologies of the longissimus, iliocostalis, and hypaxial muscles in the anterior presacral region of extant diapsida , 2007, Journal of morphology.

[19]  M J Fagan,et al.  Rigid-body analysis of a lizard skull: modelling the skull of Uromastyx hardwickii. , 2008, Journal of biomechanics.

[20]  K. Schwenk.  Morphology of the tongue in the tuatara, Sphenodon punctatus (Reptilia: Lepidosauria), with comments on function and phylogeny , 1986, Journal of morphology.

[21]  A. Russell,et al.  The Role of Phylogenetic Analysis in the Inference of Unpreserved Attributes of Extinct Taxa , 1992 .

[22]  P. O’Higgins,et al.  The head and neck muscles associated with feeding in Sphenodon (Reptilia: Lepidosauria: Rhynchocephalia) , 2009 .

[23]  Leverett Allen Adams,et al.  A MEMOIR ON THE PHYLOGENY OF THE JAW MUSCLES IN RECENT AND FOSSIL VERTEBRATES , 1918 .

[24]  T. M. Oelrich.  The anatomy of the head of Ctenosaura pectinata (Iguanidae) , 1956 .

[25]  O. Rieppel.  Feeding mechanics in Triassic stem‐group sauropterygians: the anatomy of a successful invasion of Mesozoic seas , 2002 .

[26]  C. Gans,et al.  Mastication in the tuatara, Sphenodon punctatus (reptilia: Rhynchocephalia): Structure and activity of the motor system , 1982, Journal of morphology.

[27]  Lawrence M Witmer,et al.  Archosaur adductor chamber evolution: Integration of musculoskeletal and topological criteria in jaw muscle homology , 2007, Journal of morphology.

[28]  J. Hutchinson,et al.  Analysis of hindlimb muscle moment arms in Tyrannosaurus rex using a three-dimensional musculoskeletal computer model: implications for stance, gait, and speed , 2005, Paleobiology.

[29]  K. Queiroz**,et al.  A phylogenetic analysis of lepidosauromorpha , 1988 .

[30]  H. Anderson.  The jaw musculature of the phytosaur, machaeroprosopus , 1936 .