Intracranial joint movements in the Agamid lizard Amphibolurus barbatus
Intracranial joint movements in the Agamid lizard Amphibolurus barbatus
复制标题
蜥蜴 Amphibolurus barbatus 的颅内关节运动
DOI：
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发表时间：
1981
期刊：
影响因子：
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通讯作者：
L. Clarke
中科院分区：
文献类型：
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作者：
G. Throckmorton;L. Clarke
运动在方关节，方鳞，额顶骨，和基翼关节的蜥蜴Amphibolurus rectatus从双平面cinefluorographs在60 fps拍摄，而动物饲养的蟋蟀。通过在蜥蜴头骨的选定部位放置骨钉来提高荧光电影的分辨率。使用计算机辅助数字化平板记录每个胶片帧中销的X、Y和Z坐标。然后，计算机程序为每个帧计算四个关节中的每一个的骨骼元素的角位置。
对29个咀嚼周期的研究结果表明：1）在大多数咀嚼周期的开合阶段，方头运动与下颌关节运动呈负相关;因此，当下颌张开时，方骨向前旋转，从而减少张口和延长下颌。2)方骨的运动与其他颅内关节的运动无关。3)额顶关节的运动量与Frazzetta（'62）的蜥蜴颅运动模型不一致。4)在许多咀嚼周期中，当下颌被压低时，肉质的舌头将猎物抵住上颌。5)在稳定期，方体倾向于向前旋转。
这些结果表明，在方头蛇中，运动具有两种功能：1）罗宾逊（'66）提出的在张开和闭合阶段的食物运输，以及2）史密斯（' 80）提出的在静止阶段的运动用于增加翼肌的机械优势。
Movement at the quadrate-articular, quadrate-squamosal, frontoparietal, and basipterygoid joints of the lizard Amphibolurus barbatus were measured from biplanar cinefluorographs taken at 60 fps while the animals were feeding on crickets. Resolution of the cinefluorographs was enhanced by placing tantulum pins into the lizard's skull at selected sites. The X, Y, and Z coordinates of the pins in each film frame were recorded using a computer assisted digitizing tablet. A computer program then calculated for each frame the angular position of the skeletal elements of each of the four joints.
The results from 29 chewing cycles show that in Amphibolurus: 1) During the opening and closing phases of most chewing cycles quadrate movement is negatively correlated with movement at the mandibular joint. Thus, as the jaws open, the quadrate rotates anteriorly tending to reduce gape and protracting the lower jaw. 2) Movement of the quadrate is independent of movement at the other intracranial joints. 3) The amount of movement at the frontoparietal joint is inconsistent with Frazzetta's ('62) model of lizard cranial kinesis. 4) In many chewing cycles, the fleshy tongue holds the prey against the upper jaws as the lower jaw is depressed. 5) During the stationary phase the quadrate tends to rotate anteriorly.
These results suggest that in Amphibolurus quadrate movement serves two functions: 1) food transport during the opening and closing phases as suggested by Robinson ('66), and 2) during the stationary phase the movement serves to increase mechanical advantage of the pterygoideus muscle as suggested by Smith ('80).