儿童枕骨鳞部正常解剖、解剖变异及骨折的三维CT特征

Three-dimensional CT features of occipital squama normal anatomy, anatomic variations and fractures

目的探讨儿童枕骨鳞部正常解剖、解剖变异及骨折的三维cT特征。方法回顾性分析589例患儿三维CT图像特征，所有图像均进行MIP、VR三维立体图像重组，分别观察正常枕骨鳞部的解剖、变异及骨折，总结其各自的部位、形态及其走行等鉴别诊断特征。结果433例（75．2％）患儿未见颅缝变异，其中154例与成人期枕骨鳞部解剖特征相同，279例可见后枕内联合，37例可见Kerckring．上枕骨软骨联合。排除近期外伤者，共113例（19．1％）发生解剖变异，包括未贯通缝和贯通缝，其存在部位遵循骨化发生规律。未贯通缝包括假缝23例，上正中裂19例，上枕骨正中裂4例。贯通缝包括顶间骨变异54例，缝间骨23例，副骨7例。33例同时存在两种或两种以上变异。34例（5．6％）见枕骨鳞部骨折，包括线样骨折27例，粉碎性骨折3例，凹陷骨折1例，颅缝分离3例，另外尚见3例变异合并骨折者。骨折线锐利，常为线样或折线样，走行不受骨化发生限制。结论儿童期枕骨鳞部正常解剖、解剖变异及骨折有其各自不同的三维CT特征，正确认识对准确诊断至关重要。

Objective To evaluate 3D CT features of normal anatomy, anatomic variations and fractures of occipital squama. Methods The 3D CT features on MIP, VR images were analyzed retrospectively in 589 pediatric cases. The normal anatomy, anatomic variations and fractures of occipital squama were observed respectively, and the differential diagnostic features including the individual location, appearance and extension were analyzed. Results Four hundred and thirty-three patients （75.2%） showed normal anatomy,including 154 patients with adult occipital anatomical features,279 patients with posterior intraoccipital synchondrosis, and 37 patients with Kerckring-supraoccipital synchondrosis. When cases with recent trauma history were excluded, 113 patients （19. 1%） showed anatomic variants, including unpenetrating sutures and penetrating sutures. The former could be subdivided to Mendosal sutures in 23 cases, superior median fissures in 19 cases, and midline supraoccipital fissures in 4 cases ,while the latter could be subdivided to the interparietal bone variations in 54 cases, wormian bones in 23 cases, and accessory bones in 7 cases. Two or more variations coexisted in 33 cases. The occipital squama fractures were shown in 34 cases （5.6%）,including linear fractures in 27 cases, comminuted fractures in 3 cases,with depression fracture in one case, separation of cranial sutures in 3 cases, and other fractures associated with variants in 3 cases. The fractures were sharp, or jagged, without limitation of the occification. Conclusion There are different 3 D CT features of normal anatomy, anatomic variations and fractures of occipital squama in children, which are important for making the accurate diagnosis.