骨科英文书籍精读（328）｜髌骨骨折
我们正在精读国外经典骨科书籍《Apley’s System of Orthopaedics and Fractures》，想要对于骨科英文形成系统认识，为以后无障碍阅读英文文献打下基础，请持续关注。
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The patella is a sesamoid bone in continuity with the quadriceps tendon and the patellar ligament (also called the patellar tendon). There are additional insertions from the vastus medialis and lateralis into the medial and lateral edges of the patella. The extensor 'strap’ is completed by the medial and lateral extensor retinacula (or quadriceps expansions), which bypass the patella and insert into the proximal tibia.
The mechanical function of the patella is to hold the entire extensor 'strap’ away from the centre of rotation of the knee, thereby lengthening the anterior lever arm and increasing the efficiency of the quadriceps.
The key to the management of patellar fractures is the state of the entire extensor mechanism. If the extensor retinacula are intact, active knee extension is still possible, even if the patella itself is fractured.
Mechanism of injury and pathological anatomy
The patella may be fractured, either by a direct force that cracks the bone like a tile under the blow of a hammer or by an indirect traction force that pulls the bone apart (and often tears the extensor expansions as well).
Direct injury – usually a fall onto the knee or a blow against the dashboard of a car – causes either an undisplaced crack or else a comminuted ('stellate’) fracture without severe damage to the extensor expansions.
Indirect injury occurs, typically, when someone catches the foot against a solid obstacle and, to avoid falling, contracts the quadriceps muscle forcefully. This is a transverse fracture with a gap between the fragments.
---from 《Apley’s System of Orthopaedics and Fractures》
重点词汇整理：
sesamoid/ˈsesəˌmɔɪd/adj. 籽骨的；芝麻形的n. 籽骨，种子软骨
vastus medialis and lateralis股内侧肌和外侧肌
vastus 股肌
retinacula支持带
bypass the patella and insert into the proximal tibia.绕过髌骨，插入胫骨近端。
bypass /ˈbaɪpæs/n. 旁路，支路；旁通管，分流术v. 绕过，避开；忽视，
tile /taɪl/n. 瓷砖，瓦片
stellate /'stelet/adj. 星形的，似星的；放射线状的
有道翻译（仅供参考，建议自己翻译）：
髌骨骨折
髌骨是与股四头肌腱和髌骨韧带(也叫髌腱)相连的籽骨。从股内侧肌和外侧肌到髌骨内侧和外侧边缘还有额外的插入器。伸肌“带”由内侧和外侧伸肌支持肌(或股四头肌扩张肌)完成，它绕过髌骨并插入胫骨近端。
髌骨的机械功能是保持整个伸肌“带”远离膝关节旋转中心，从而延长前杠杆臂，提高股四头肌的效率。处理髌骨骨折的关键是整个伸肌机制的状态。如果伸肌支持带完好，即使髌骨本身骨折，仍可进行主动膝关节伸展。
髌骨可能骨折，要么是由直接的力量像瓦片一样在锤子的打击下使骨头破裂，要么是由间接的牵引力将骨头拉裂(通常也会撕裂伸肌扩张)。
直接伤害——通常是摔在膝盖上或撞在汽车仪表板上——会导致unis 放置裂缝或粉碎性(星状)骨折，但不会对伸肌扩张造成严重损伤。一般来说，当一个人的脚碰到坚实的障碍物，为了避免摔倒，会导致股四头肌强力收缩，间接伤害就会发生。这是骨折碎片之间有间隙的横向骨折。