A FUNCTIONAL-ANALYSIS OF CARNASSIAL BITING
A FUNCTIONAL-ANALYSIS OF CARNASSIAL BITING
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DOI：
10.1111/j.1095-8312.1983.tb01596.x
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发表时间：
1983-01-01
影响因子：
1.9
通讯作者：
GREAVES, WS
中科院分区：
文献类型：
--
作者：
GREAVES, WS
使用理想模型研究食肉动物的颌骨机制（Greaves，1978）。该模型假设：头部两侧的肌肉活动，以及在食肉动物的咬合过程中，下颌关节和食肉动物的牙齿是下颌之间的单点接触。该模型作出以下预测：在食肉动物与carnassial牙齿的下颌肌肉的合力将被定位。从颌关节到牙齿的60%的距离，这样的安排可以提供最大的咬合力，同时提供合理的开口宽度（记住咬合力和张口不能同时最大化）;从进化的意义上说，如果在食肉牙齿处需要更大的咬合力，那么要么动物会变得更大以提供非常大的咬合力，要么肌肉的结构可能会改变，例如，变得更羽状，但是颚的几何形状（即，颌关节、食肉齿和肌肉合力的相对位置）将不会改变;如果需要更大的张口，则动物将变得更大以便具有更长的颌并因此具有绝对更宽的张口或改变其肌肉结构以允许更大的伸展同时几何形状保持不变;并且在具有更长剪切区域的动物中（例如，灭绝的鬣狗）剪切区域将是. apprx。20%的颌长度，肌肉合力将位于从颌关节到最前剪切齿的大约60%的距离处。
The jaw mechanism of carnivores is studied using an idealized model (Greaves, 1978). The model assumes: muscle activity on both sides of the head, and that the jaw joints and the carnassial teeth are single points of contact between the lower jaw during carnassial biting. The model makes the following predictions: in carnivores with carnassial teeth the resultant force of the jaw muscles will be positioned .apprx. 60% of the way from the jaw joint to the tooth, an arrangement which delivers the maximum bite force possible together with a reasonably wide gape (remembering that bite force and gape cannot both be maximized); in an evolutionary sense, if greater bite force is required at the carnassial tooth, either the animal will get larger so as to deliver an aboslutely larger bite force or the architecture of the muscles may change, becoming more pinnate, for example, but jaw geometry (i.e., the relative positions of the jaw joints, the carnassial tooth and the muscle resultant force) will not change; if greater gape is required, the animal will get larger so as to have longer jaws and therefore an absolutely wider gape or change its muscle architecture allowing for greater stretch while the geometry remains unchanged; and in animals with a longer shearing region (e.g., the extinct hyaenodonts) the shearing region will be .apprx. 20% of jaw length and the muscle resultant force will be positioned approximately 60% of the way from the jaw joint to the most anterior shearing tooth.