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Gheorghe TI, Leekam R, Lam EWN, Perschbacher S, Liebgott B, Agur AMR. A dynamic ultrasonographic in vivo study of the musculoaponeurotic architecture of the human masseter muscle. Oral Surg Oral Med Oral Pathol Oral Radiol 2021; 132:609-615. [PMID: 33781750 DOI: 10.1016/j.oooo.2021.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/01/2021] [Accepted: 02/06/2021] [Indexed: 12/13/2022]
Abstract
OBJECTIVE In the present study, we sought to investigate the in vivo musculoaponeurotic architecture of the masseter muscle (MM) volumetrically with ultrasound in asymptomatic participants. It was hypothesized that the mean fiber bundle length (FBL) and mean aponeurotic height of laminae of the MM differ significantly between the relaxed state and maximally contracted state upon elevation of the mandible. STUDY DESIGN The MM was investigated volumetrically in 12 male and 12 female asymptomatic participants (mean age, 25.8 ± 4.1 years) using ultrasound. The mean FBL and mean height of aponeuroses in the relaxed and maximally contracted states were compared using paired t tests, with significance established at P ≤ .05. Intrarater reliability was assessed using the intraclass correlation coefficient (ICC). RESULTS The MM consisted of the superficial head (SH) and deep head, each arranged in multiple laminae. Fiber bundles extended between superior and inferior aponeuroses and/or bone. Statistically significant differences (P ≤ .05) were observed in mean FBL and in mean height of aponeuroses between the relaxed and contracted states only in superficial laminae of the SH. CONCLUSIONS These results suggest there is differential contraction of the laminae of the MM in the transition from relaxed to contracted states. Future comparison with pathologic patients can be made on the basis of an established normative database.
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Affiliation(s)
- Teodora-Iunia Gheorghe
- Division of Anatomy, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Oral and Maxillofacial Radiology Graduate Program, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada.
| | - Roger Leekam
- Division of Anatomy, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Ernest W N Lam
- Oral and Maxillofacial Radiology Graduate Program, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada; Graduate Department of Dentistry, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Susanne Perschbacher
- Oral and Maxillofacial Radiology Graduate Program, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada; Graduate Department of Dentistry, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Bernard Liebgott
- Division of Anatomy, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Graduate Department of Dentistry, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
| | - Anne Maria Reet Agur
- Division of Anatomy, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Graduate Department of Dentistry, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada
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Shan X, Otsuka S, Yakura T, Naito M, Nakano T, Kawakami Y. Morphological and mechanical properties of the human triceps surae aponeuroses taken from elderly cadavers: Implications for muscle-tendon interactions. PLoS One 2019; 14:e0211485. [PMID: 30735517 PMCID: PMC6368299 DOI: 10.1371/journal.pone.0211485] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 01/15/2019] [Indexed: 11/21/2022] Open
Abstract
The human triceps surae (two gastrocnemii and soleus) has aponeuroses in the proximal and distal aspects, the latter of which insert into the calcaneus by sharing the common Achilles tendon. These tendinous tissues are known to have elasticity and upon muscle contraction the aponeurosis is stretched both longitudinally (along the muscle’s line of action) and transversely. Higher aponeurosis transverse deformability has been documented, but there is a paucity of information on the morphology and mechanical properties of human aponeurosis. This study aimed to identify morphological and mechanical characteristics of the human triceps surae aponeuroses. Twenty-five triceps surae muscle-tendon units were procured from 13 human donors (formalin fixed, 6 males, 7 females) aged 67–91 years. Specimens of aponeuroses were excised from the eight regions (posterior and anterior regions of the gastrocnemius medialis and lateralis, medial and lateral parts of soleus; proximal, middle, and distal sites each, 2–4 cm × 2–4 cm). Aponeurosis thickness was measured using a digital caliper. Uniaxial tensile tests were implemented to determine the mechanical properties of specimens loaded longitudinally (along the muscle’s line of action) and transversely. The aponeurosis thickness showed significant differences between muscles and sites, while Young’s modulus showed direction-dependent (longitudinal vs. transverse) differences within sites. Results show different morphology and mechanical properties of aponeuroses between synergist muscles. The reason for site-dependent differences in stiffness is due to a reduced aponeurosis thickness rather than a reduction in the material property. The anisotropic elastic feature (differences between longitudinal and transverse directions) of the aponeuroses was more pronounced than previous in vivo findings, suggesting inherent material design of the aponeurosis that matches three-dimensional contractile behavior of muscle fibers.
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Affiliation(s)
- Xiyao Shan
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
- Department of Anatomy, Aichi Medical University, Nagakute, Aichi, Japan
| | - Shun Otsuka
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
- Department of Anatomy, Aichi Medical University, Nagakute, Aichi, Japan
| | - Tomiko Yakura
- Department of Anatomy, Aichi Medical University, Nagakute, Aichi, Japan
| | - Munekazu Naito
- Department of Anatomy, Aichi Medical University, Nagakute, Aichi, Japan
| | - Takashi Nakano
- Department of Anatomy, Aichi Medical University, Nagakute, Aichi, Japan
| | - Yasuo Kawakami
- Faculty of Sport Sciences, Waseda University, Tokorozawa, Saitama, Japan
- Department of Anatomy, Aichi Medical University, Nagakute, Aichi, Japan
- * E-mail:
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