Clark J, Stechschulte D J
Department of Orthopaedics, University of Washington, Seattle 98195, USA.
J Anat. 1998 May;192 ( Pt 4)(Pt 4):605-16. doi: 10.1046/j.1469-7580.1998.19240605.x.
Traumatic avulsions of ligament or tendon insertions rarely occur at the actual interface with bone, which suggests that this attachment is strong or otherwise protected from injury by the structure of the insertion complex. In this study we describe the terminal extent of quadriceps tendon fibres where they insert into the patellae of adult rabbits, humans, dogs and sheep. Specimens were examined by scanning electron microscopy (SEM) and light microscopy (LM). To facilitate tracing of tendon fibres the specimens were decalcified for SEM, and polarised light microscopy (PLM) was used in the LM segment of the study. By SEM it was possible to identify mature bone by the presence of osteocytes and a lamellar organisation. PLM and SEM showed that, unlike tendon fibres elsewhere, those in the calcified fibrocartilage were not crimped. No specific cement line was identified by SEM. Tendon fibres interdigitated among separate bone lamellar systems, (osteons or marrow spaces), but did not merge with the collagen systems of individual lamellae. The interdigitation was more extensive and the margin between tendon and bone was less distinct in the anterior third of the insertion. The segment of calcified tendon which interdigitated with bone stained less intensely blue and was less cellular than the more proximal calcified fibrocartilage zone adjacent to the tidemark. Lamellar collagen fibres of the bony trabeculae in the anterior patella were unusually parallel and longitudinal in orientation, making distinction of interposed tendon fibres difficult on LM and PLM sections. LM, SEM and transmission electron microscopy of rabbit patellae at birth revealed that anterior quadriceps tendon fibres extended over the patella in a fibrous cellular layer. By 2 wk of age, this layer had acquired chondroid features (i.e. cell lacunae and metachromasia) and contained vessels extending from patellar marrow. At 6 wk of age, part of this fibrocartilaginous layer was replaced by mature bone and osteoid. In the young adult animal, the quadriceps tension interdigitates extensively with the patellar bone. This segment of the insertion is perhaps the remnant of calcified fibrocartilage which has been remodelled by bone formation.
韧带或肌腱附着处的创伤性撕脱很少发生在与骨的实际界面处，这表明这种附着很强，或者因附着复合体的结构而受到保护不易受伤。在本研究中，我们描述了成年兔、人、狗和羊的股四头肌肌腱纤维插入髌骨的末端范围。通过扫描电子显微镜（SEM）和光学显微镜（LM）对标本进行检查。为便于追踪肌腱纤维，标本进行脱钙处理以用于SEM，并且在研究的LM部分使用偏振光显微镜（PLM）。通过SEM，可通过骨细胞的存在和板层结构来识别成熟骨。PLM和SEM显示，与其他部位的肌腱纤维不同，钙化纤维软骨中的肌腱纤维没有卷曲。SEM未识别出特定的黏合线。肌腱纤维在单独的骨板层系统（骨单位或骨髓腔）之间相互交错，但未与单个板层的胶原系统融合。在插入部的前三分之一处，交错更为广泛，肌腱与骨之间的边界不太明显。与骨相互交错的钙化肌腱段比靠近潮线的近端钙化纤维软骨区染色更浅，细胞更少。髌骨前部骨小梁的板层胶原纤维异常平行且呈纵向排列，使得在LM和PLM切片上难以区分其间的肌腱纤维。对出生时兔髌骨的LM、SEM和透射电子显微镜检查显示，股四头肌前部肌腱纤维在髌骨上延伸形成纤维细胞层。到两周龄时，该层具有类软骨特征（即细胞腔隙和异染性），并含有从髌骨髓延伸而来的血管。六周龄时，该纤维软骨层的一部分被成熟骨和类骨质取代。在年轻成年动物中，股四头肌张力与髌骨头广泛交错。插入部的这一段可能是已通过骨形成重塑的钙化纤维软骨的残余部分。
