Muscle Architecture and Structural Model of the Human Tongue

120 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2005.The human tongue plays a principal role in speech, swallowing, and respiration. It is mainly composed of muscles, which have complex bundle arrangement and interdigitation among them. The knowledge of three-dimensional muscle architecture is critical for understanding the complicated motor functions of human tongues. The present study used high-resolution MRI to study the human tongue structure on the macro- and microscopic levels. Later, the microscopic MRI data were validated by the corresponding histologic section: The "dark" areas in MRI slices were muscle and collagenous tissue, whereas the "bright" areas were adipose tissue. On the other hand, the intra- and intersectional distortions in the histologic sections seemed to be unavoidable and existed with unpredictable patterns. Additionally, the courses of muscles and interdigitation between muscles were described. The transversus and verticalis bundles formed alternating parallel muscle layers in the planes orthogonal to the longitudinal axis throughout the whole length of the tongue. The styloglossus and hyoglossus decussated in the middle region, and then extended to the lateral sides of the tongue. A pair of "unknown muscles" was found hidden in the genioglossus. Their bundles were orthogonal to the genioglossus bundles, but did not connect with the hyoglossus or inferior lingualis. Further, the computational structural models of the human tongue were developed in surface meshes and tetrahedral grids based on the result of segmentation. In conclusion, MRI is the optimal tool to study complex muscle architecture. It can provide three-dimensional digital information, based on which accurate structural models are developed. The present study has built the structural model of the human tongue successfully.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD