The understanding of musculoskeletal structure and function is an integral part of clinical anatomy courses.  Skeletal muscle architecture has been studied in two- dimensions resulting in models where muscle fiber orientation was over simplified with a single pennation angle and fiber length, thus assuming that the architecture was uniform throughout the volume of the muscle.  Similarly innervation patterns have been documented in 2-D, using various methods of serial dissection.  In our laboratory, 3-D coordinates of hundreds of muscle fiber bundles from the cadaveric soleus and gastrocnemius muscles were obtained by digitizing the points from a serially dissected specimen using a Microscribe 3DX digitizer.  A new volumetric model based on B-spline basis functions was designed to reconstruct and document internal fiber architecture throughout the muscle. The 3-D model allows visualization of the whole muscle or any component part to the level of individual fiber bundles from any perspective (http://dante.med.utoronto.ca/skeletalmuscle/).  The branches of the tibial nerve innervating the soleus were digitized and then viewed in 3-D within the volume of the muscle. Muscle architecture and innervation were found to be far more complex than previously documented.  The model can be used in large and small group teaching sessions and for self-study to help the student gain a better understanding of 3-D structure and function.

The 3-D B-spline model is the first model to capture the detailed fiber architecture and innervation of a human muscle in situ. The fully manipulatable 3-D model can be used as an innovative teaching tool to demonstrate muscle structure and its relationship to function. In the research setting the model is used to visualize and measure muscle architectural parameters and innervation patterns to refine our understanding of muscle function. The model has been created to permit visualization of muscle contraction.

Anne Agur
Division of Anatomy, Department of Surgery,
Medical Sciences Building Room 1158,
University of Toronto,
Toronto, Ontario, Canada M5S 1A8
Phone: 416-978-8855
Fax: 416-978-3844
Email: anne.agur@utoronto.ca

CO-AUTHORS:
V. Ng-Thow-Hing, E. Loh, N.H. McKee
same as above
Phone: same as above
Fax: same as above
Email: n.mckee@utoronto.ca
eloh@uwo.ca
vngthowhing@hra.com