Examination of the microstructures of the lower cervical facet based on micro-computed tomography: A cadaver study

The cervical facet has complicated 3D microstructures and inhomogeneities. The cervical facet joint, which also participates in the formation, plays a certain role in regulating and limiting the movement of the spine. Correct identification and evaluation of its microstructure can help in the diagnosis of orthopedic disease and predict early phases of fracture risk. To evaluate the safety of the cervical spine by measuring and analyzing the microstructures and morphometric parameters of bone trabeculae in the normal cervical facet with high-resolution 3D micro-computed tomography. Thirty-one sets of C3 to C7 lower cervical vertebrae (155 vertebrae) were scanned using micro-computed tomography. The morphological characteristics and direction of trabecular bone in the facet of the lower cervical vertebrae were observed by selecting and rebuilding the areas of interest, and the changes in the microstructure of the areas of interest were calculated to reveal the structural characteristics and weak areas. Images indicated an ossified center between the superior and inferior articular processes of the lower cervical spine. The cellular bone trabeculae of the articular process had complex reticular microstructures. The trabecular bone plate near the cortical bone was lamellar and relatively dense, and it extended around and transformed into a network structure, and then into the rod-shaped trabecular bone. The rod-shaped trabeculae converged with the plate-shaped trabeculae with only 1 to 2 layers surrounding the trabeculae cavity. Statistical results of the morphological parameters of the trabecular bone showed that trabecular bone volume fraction values were significantly higher for C7 than for C3 to C6 (P < .05). There were significant differences between C7 and C3 to C5 and between C6 and C4 in bone surface area/bone volume (P < .05). There was a significant difference between C7 and C3 to C6 in trabecular bone thickness values (P < .05). The degree of anisotropy value was significantly smaller for C3 than for C6 and C7 (P < .05). The changes in the C3 to C7 microstructure were summarized in this study. The loading capacity and stress of the C7 articular process tended to be limited, and the risk of injury tended to be higher for the C7 articular process.