Three-dimensional structure of the human temporalis muscle

Eijden, T.M.G.J. van; Koolstra, J.H.; Brugman, P.

doi:10.1002/(sici)1097-0185(199612)246:4<565::aid-ar17>3.0.co;2-m

Cited by 57 publications

(35 citation statements)

References 19 publications

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“…Within the muscle regional differences exist in length, spatial orientation and position of muscle fibres, and in cross-sectional area (Van Eijden et al 1996, 1997. Hence, during jaw movements fibre and sarcomere excursions are not the same for various muscle portions, and as a consequence the maximum force and excursion range of the muscle portions differ.…”

Section: mentioning

confidence: 99%

Regional differences in fibre type composition in the human temporalis muscle

Korfage

Eijden

1999

Journal of Anatomy

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Anatomical and electromyographic studies point to regional differences in function in the human temporalis muscle. During chewing and biting the anterior portions of the muscle are in general more intensively activated and they are capable of producing larger forces than the posterior portions. It was hypothetised that this heterogeneity in function is reflected in the fibre type composition of the muscle. The composition and surface area of different fibre types in various anteroposterior portions of the temporalis muscle were investigated in 7 cadavers employing immunohistochemistry with a panel of monoclonal antibodies against different isoforms of myosin heavy chain. Pure slow muscle fibres, type I, differed strongly in number across the muscle. In the most posterior portion of the muscle there were 24 % type I fibres, in the intermediate portion 57 %, and in the most anterior portion 46 %. The mean fibre cross-sectional area (m-fcsa) of type I fibres was 1849 µm#, which did not differ significantly across the muscle. The proportion of pure fast muscle fibres, type IIA and IIX, remained more or less constant throughout the muscle at 13 % and 11 % respectively ; their m-fcsa was 1309 µm# and 1206 µm#, respectively, which did not differ significantly throughout the muscle. Pure type IIB fibres were not found. The relative proportion of hybrid fibres was 31 % and did not differ significantly among the muscle portions. Fibre types IjIIA and cardiac αjIjIIA were the most abundant hybrid fibre types. In addition, 5 % of the type I fibres had an additional myosin isoform which has only recently been described by means of electrophoresis and was named Ia. In the present study they were denoted as hybrid type IjIa muscle fibres. It is concluded that intramuscular differences in type I fibre distribution are in accordance with regional differences in muscle function.

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Section: mentioning

confidence: 99%

Regional differences in fibre type composition in the human temporalis muscle

Korfage

Eijden

1999

Journal of Anatomy

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“…Often, the muscle is divided into an anterior and posterior temporalis. We defined six anteroposterior muscle portions (for an extensive description, see van Eijden et al, 1996). The so-called anterior temporalis was defined in the present study to be constituted by the three anteriormost portions and the posterior temporalis by the three posteriormost portions.…”

Section: Jaw-closing Musclesmentioning

confidence: 99%

“…Information about sarcomere length in the human is scarce. Recently, we reported about measured sarcomere lengths at the closed-jaw position in cadavers and estimated the effect of jaw position on sarcomere length and relative muscle tension by using a mathematical model (van Eijden and Raadsheer, 1992;van Eijden et al, 1995van Eijden et al, , 1996. The results pointed to differential stretching of sarcomeres and consequently to a heterogeneous distribution of tension when sarcomeres of the same muscle and of different muscles were compared.…”

mentioning

confidence: 99%

“…So far, most models have been confined to the static biomechanical performance of the system. More recently, however, dynamic models have been developed, which allow for the analyses of the effect of jaw muscle tension on jaw motions and vice versa van Eijden, 1995, 1996). Because of the length-tension and force-velocity relationships, these dynamic models require information about sarcomere length in both jaw-closing and jaw-opening muscles during jaw motion, and they should take into account the effect of muscle architecture on, e.g., muscle force output.…”

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confidence: 99%

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Architecture of the human jaw‐closing and jaw‐opening muscles

1997

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Background: The human jaw-closing and jaw-opening muscles produce forces leading to the development of three-dimensional bite and chewing forces and to three-dimensional movements of the jaw. The length of the sarcomeres is a major determinant for both force and velocity, and the maximal work, force, and shortening range each muscle is capable of producing are proportional to the architectural parameter volume, physiological cross-sectional area, and fiber length, respectively. In addition, the mechanical role the muscles play is strongly related to their three-dimensional position and orientation in the muscle-bone-joint system. The objective of this study was to compare relevant architectural characteristics for the jaw-closing and jaw-opening muscles and to provide a set of data that can be used in biomechanical modeling of the masticatory system.Methods: In eight cadavers, sarcomere lengths, muscle masses, fiber lengths, pennation angles, and physiological cross-sectional areas were determined for the following muscles: superficial and deep masseter, anterior and posterior temporalis, anterior and posterior medial pterygoid, inferior and superior lateral pterygoid, posterior and anterior digastric, geniohyoid, posterior and anterior mylohyoid, and stylohyoid. To determine the spatial position of their action lines, the threedimensional coordinates of the attachment sites were registered.Results: Compared with the jaw openers, the jaw closers were characterized by shorter sarcomere lengths at the closed jaw, larger masses of contractile and tendinous tissue, larger physiological cross-sectional areas, larger pennation angles, shorter fiber lengths, shorter moment arms, and lower fiber-length-to-muscle-length ratios. In addition, architectural features differed across the muscles of the same functional group. Sarcomere length did not differ significantly among the regions of the same muscle. In contrast, in some muscles, significant intramuscular differences were found with respect to, e.g., physiological cross-sectional area, fiber length, pennation angle, and moment arm length. Conclusions:The results suggest that the jaw-closing muscles have architectural features that suit them for force production. Conversely, the jaw-opening muscles are better designed to produce velocity and displacement. Anat. Rec., 248:464-474, 1997. r 1997 Wiley-Liss, Inc.Key words: jaw muscles; sarcomere length; muscle mass; fiber length; pennation angle; physiological cross-section; action line; moment armThere exists a close relationship between muscle structure and muscle function. First, the tension that can be generated by a muscle depends on the degree of overlap between the actin and myosin filaments and, consequently, on the length of the sarcomeres. Because of the length-tension relationship of the sarcomeres, maximum active tension can be developed at optimum sarcomere length and decreases with greater and with shorter lengths (Gordon et al., 1966).Second, within a muscle, the fibers can be arranged in a complex ge...

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“…The external loading force is transmitted into the tissues in a heterogeneous manner based on the structure and mechanical properties of the tissue; therefore, the response of each region in the tissue to the external loading force is spatially different. The heterogeneity in the transmission of the external loading force into the tissue is essential for the maintenance of the tissue structure [2,3]. However, it is difficult to examine the biomechanical effects of the external loading force on the tissues because there is no apparatus that can measure the local surface strain and local stiffness simultaneously.…”

Section: Introductionmentioning

confidence: 99%

Development of a device to stretch tissue-like materials and to measure their mechanical properties by scanning probe microscopy

2007

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We developed a new stretch device to investigate the biomechanical responses to an external loading force on a tissue-like material consisting of cells and a collagen gel. Collagen gel, a typical matrix found abundantly in the connective tissue, was attached to an elastic chamber that was precoated with a thin layer of collagen. Madin-Darby canine kidney (MDCK) cells that were cultured on the collagen gel were stretched in a uniaxial direction via deformation of the elastic chamber. Changes in the morphology and stiffness of the tissue-like structure were measured before and after the stretch by using wide-range scanning probe microscopy (WR-SPM). The change in cellular morphology was heterogeneous, and there was a 2-fold increase in the intercellular junction due to the stretch. In addition to the SPM measurements, this device enables observation of the spatial distribution of cytoskeletal proteins such as vimentin and α-catenin by using immunofluorescent microscopy. We concluded that the stretch device we have reported in this paper is useful to measure the mechanical response of a tissue-like material over a range of cell sizes when exposed to an external loading force.

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Three-dimensional structure of the human temporalis muscle

Cited by 57 publications

References 19 publications

Regional differences in fibre type composition in the human temporalis muscle

Regional differences in fibre type composition in the human temporalis muscle

Architecture of the human jaw‐closing and jaw‐opening muscles

Development of a device to stretch tissue-like materials and to measure their mechanical properties by scanning probe microscopy

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