Rönning O, Kantomaa T
Institute of Dentistry, University of Oulu, Finland.
J Anat. 1988 Aug;159:173-9.
The mode of growth of the rat clavicle from 17 to 45 days of age was studied by means of vital staining (alizarin red S), histology and autoradiography (tritiated thymidine). In addition the clavicle on one side was subjected to periostomy at the age of 10 days and its length compared with that of its unoperated counterpart at the ages of 17 and 45 days. The alizarin red staining revealed that the medial end of the clavicle contributes to the length of the bone, while the lateral end appears to have mainly an articulatory function. Histologically, the medial end cartilage closely resembles the condylar cartilage of the mandible, whereas the lateral end appears to be composed of two cartilaginous structures separated by a mesenchymatous layer. Tritiated thymidine was deposited in the mesenchymal cells covering the medial end cartilage, whereas virtually no activity was observed in the mesenchyme of the lateral end cartilage. The periostomised clavicle was more slender in appearance than its control throughout the observation period. The two clavicles were of the same length at 17 days, but by 45 days the periostomised clavicle was significantly longer than the control. It is suggested that the growth of the clavicle is essentially comparable to the growth of the mandible. Length growth occurs in response to the action of the surrounding structures, while analogously to the mandibular condyle, the medial end cartilage actively translates the bone in a direction perpendicular to the articular surface, giving rise to its curved shape.
通过活体染色（茜素红S）、组织学和放射自显影术（氚标记胸腺嘧啶核苷）研究了17至45日龄大鼠锁骨的生长方式。此外，在10日龄时对一侧锁骨进行骨膜造口术，并将其长度与17日龄和45日龄时未手术的对侧锁骨长度进行比较。茜素红染色显示，锁骨内侧端对骨的长度有贡献，而外侧端似乎主要具有关节功能。组织学上，内侧端软骨与下颌骨髁突软骨非常相似，而外侧端似乎由两层被间充质层分隔的软骨结构组成。氚标记胸腺嘧啶核苷沉积在覆盖内侧端软骨的间充质细胞中，而在外侧端软骨的间充质中几乎未观察到活性。在整个观察期内，接受骨膜造口术的锁骨外观比其对照更细长。17日龄时，两根锁骨长度相同，但到45日龄时，接受骨膜造口术的锁骨明显比对照长。有人提出，锁骨的生长与下颌骨的生长基本相当。长度的增长是对周围结构作用的反应，而下颌骨髁突类似，内侧端软骨沿垂直于关节面的方向主动平移骨，使其形成弯曲形状。
