The biomechanics of the human tongue

Includes abstract.Includes bibliographical references (p. 137-148).The human tongue is composed mainly of skeletal-muscle tissue, and has a complex architecture. Its anatomy is characterised by interweaving, yet distinct muscle groups. It is a significant contributor to the phenomenon of Obstructive Sleep Apnea (OSA). OSA is a pathological condition defined as the partial or complete closing of any part of the human upper airway (HUA) during sleep. OSA syndrome affects a significant portion of the population. Patients with OSA syndrome experience various respiratory problems, an increase in the risk of heart disease, a significant decrease in productivity, and an increase in motor-vehicle accidents [58]. The aim of this work is to report on a constitutive model for the human tongue, and to demonstrate its use in computational simulations for OSA. A realistic model of the constitution of the tongue and computational simulations are also important in areas such as linguistics and speech therapy [44]. The detailed anatomical features of the tongue have been captured using data from the Visible Human Project (VHP) [102]. The geometry of the tongue, and each muscle group of the tongue, are visually identified, and its geometry captured using Mimics [100]. Various image processing tools available in Mimics, such as image segmentation, region-growing and volume generation were used to form the three-dimensional model of the tongue geometry. Muscle fibre orientations were extracted from the same dataset, also using Mimics.The muscle model presented here is based on Hill’s three-element model for representation of the constituent parts of muscle fibres. This Hill-type muscle model also draws from recent work in muscle modelling, by Martins [88]. The model is implemented in an Abaqus user element (UEL) subroutine [24]. The transversely isotropic behaviour of the muscle tissue is accounted for, as well as the influence of muscle activation. The mechanics of the model is limited to static, small-strain, anisotropic, linear-elastic behaviour, and the governing equations are suitably linearized. The body position of the patient during an apneic episode is accounted for in the simulations, as well as the effect of gravity. The focus of this study is on tongue muscle behaviour under gravitational loading, simulating a simplified OSA event. Future models will incorporate airway pressure as well. The behaviour of the model is illustrated in a number of benchmark tests, and computational examples

2005 Conference on Auditory and Visual Speech Processing FINITE ELEMENT MODELING OF THE TONGUE

There is an increased need to study the human oropharyngeal anatomy for research in speech production, feeding motion, and breathing activities. Computational anatomic models are also useful to conduct virtual experiments withou

An improved 3D dynamical finite element model of tongue muscles

International audienceThis work aims to present the last significant improvements of the three-dimensional (3D) biomechanical finite element model of the tongue used within our group. The model, based on medical images of a specific patient, has been originally developed by Gérard and colleagues and has undergone significant adaptations and improvements through the past ten years. The new model, made of a full-hexahedral mesh, presents the implementation of 11 groups of intrinsic and extrinsic muscles. The anatomical location of these muscles is defined via various subsets of elements in the mesh derived from the previous works. Fibers from older models are transferred within the new version of the tongue using a semi-automatic method that insure their symmetry with the sagital plane and a consisting repartition inside the tongue volume. Within the 3D model, a distributed lambda model, based on Feldman’s lambda Model implemented by Nazari and colleagues, is used to describe the finite- element activation of muscles. The new 3D finite element modeling of the tongue muscles offered the opportunity to investigate the role of each muscle and above all the debated role of the styloglossus. The integration of the tongue model within a 3D biomechanical model of the vocal tract aims to achieve an accurate modeling of swallowing. It consists in developing a fluid model which may represents the food bolus and its interaction with the mechanical structures of the vocal tract