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

Abstract

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 Kerckringsupraoccipital 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 3D CT features of normal anatomy,anatomic variations and fractures of occipital squama in children,which are important for making the accurate diagnosis. Key words: Child; Occipital bone; Fractures,bone; Anatomy,comparative