Beecher R M
J Morphol. 1979 Jan;159(1):117-30. doi: 10.1002/jmor.1051590109.
The purpose of this investigation was to relate the morphology of connective tissues in the mandibular symphysis to the behavioral and experimental evidence for mobility and mechanical stress at the symphysis. The anatomy of the symphysis was examined histologically in 6 mammalian orders encompassing 22 species. Behavioral and experimental evidence of stress during the power stroke of the chewing cycle correspond with stresses at the symphysis implied by the location and orientation of symphyseal connective tissues. These stresses are: (1) dorsoventral shear of the symphysis due to the transfer of force from balancing to chewing sides, (2) bending of the symphysis causing tension along the inferior and compression along superior borders due to torsion on the dentaries from the jaw closing muscles, and (3) antero-posterior shear of the symphysis due to an anteriorly directed stress on the chewing side. Interspecific comparisons suggest that leaf eaters can resist greater dorsoventral shear than fruit or insect eaters, but no correlations exist between diet and bending or antero-posterior shear. This suggests that chewing leaves requires larger biting forces.
本研究的目的是将下颌联合处结缔组织的形态与联合处活动及机械应力的行为学和实验证据联系起来。对涵盖22个物种的6个哺乳动物目下颌联合处的解剖结构进行了组织学检查。咀嚼周期动力冲程期间应力的行为学和实验证据与联合处结缔组织的位置和方向所暗示的联合处应力相对应。这些应力包括：(1) 由于力从平衡侧转移到咀嚼侧而导致联合处的背腹剪切力；(2) 联合处弯曲，由于咬肌使齿骨扭转，导致联合处下缘受拉、上缘受压；(3) 由于咀嚼侧向前的应力而导致联合处的前后剪切力。种间比较表明，食叶动物比食果或食虫动物能承受更大的背腹剪切力，但饮食与弯曲或前后剪切力之间不存在相关性。这表明咀嚼树叶需要更大的咬合力。
