Herring S W, Mucci R J
Department of Orthodontics, University of Washington, Seattle 98195.
J Morphol. 1991 Mar;207(3):225-39. doi: 10.1002/jmor.1052070302.
Although cranial sutures presumably play a role in absorbing and/or transmitting loads applied to the skull, loading patterns on facial sutures are poorly understood. The zygomatic arch provides a comparatively isolated mechanical part of the skull containing a single suture, the zygomatico-squamosal. In pigs the zygomatico-squamosal suture has a short vertical segment located within the postorbital process and a longer horizontal segment which extends posteriorly. In anesthetized pigs single-element high-elongation strain gages were bonded over both segments of the suture. Strain was recorded during stimulation of the masseter muscles and while the lightly anesthetized animals masticated food pellets. The predominant strain patterns differed in the two segments of the suture. During mastication compressive strains predominated in the vertical segment, but tensile strains predominated in the horizontal segment. The same patterns were also produced by stimulation of the ipsilateral masseter muscle. Contraction of the contralateral masseter reversed the strain pattern, but strain levels were low and during mastication such reversals occurred only transiently. The two segments of the suture have contrasting morphologies. The vertical segment has broad, interdigitating contacts with fibers arranged in a compression-resisting orientation. The horizontal segment has a simple tongue and groove structure with fibers arranged to resist tension. Thus, the structure of the suture reflects the predominant strain pattern.
尽管颅缝可能在吸收和/或传递施加于颅骨的负荷方面发挥作用，但面部缝的负荷模式却知之甚少。颧弓提供了颅骨中一个相对孤立的机械部分，其中包含一条单一的缝，即颧颞缝。在猪身上，颧颞缝有一个位于眶后突内的短垂直段和一个向后延伸的较长水平段。在麻醉的猪身上，将单元件高伸长应变片粘贴在缝的两段上。在刺激咬肌时以及轻度麻醉的动物咀嚼食物颗粒时记录应变。缝的两段中主要的应变模式不同。在咀嚼过程中，垂直段以压缩应变为主，但水平段以拉伸应变为主。刺激同侧咬肌也会产生相同的模式。对侧咬肌的收缩会使应变模式逆转，但应变水平较低，且在咀嚼过程中这种逆转仅短暂发生。缝的两段具有截然不同的形态。垂直段与以抗压方向排列的纤维有宽阔的、相互交错的接触。水平段具有简单的榫槽结构，其纤维排列成抗张形式。因此，缝的结构反映了主要的应变模式。
