Variation in the morphology of spinous processes in the cervical spine – An objective and parametric assessment based on CT study

BACKGROUND: Typically, cervical vertebrae display bifid spinous processes. Nevertheless, this feature may vary both between subjects and even within the vertebrae of the same individual. Although such variation can be important in archaeological research, anthropological studies and forensic medicine, it has not so far been the subject of any detailed studies. MATERIAL AND METHODS: An analysis of 200 cervical spine CT examinations was performed. The morphology of the spinous process was evaluated, and new anthropometric parameters were selected to allow a more precise quantitative analysis of the degree of bifidity. RESULTS: The spinous process base (i.e. the part of the spinous process which was not bifid) was significantly longer in CII and CVII than in the other vertebrae. The spinous process branches (bifid elements) were significantly longer in CVI and CVII than in the other vertebrae. The angle between the branches was significantly sharper in CII and CVII than in CIII-CVI, on the right side, and CIII-CV, on the left side. On the right side, the branching coefficient (degree of branch development) was significantly higher for CII and significantly lower for CVI-CVII than for the other vertebrae. On the left side, the coefficient was significantly higher for CII and CIV, and significantly lower for CVI-CVII, compared to the other vertebrae. CONCLUSION: Our findings highlight new objective parameters of morphological variability in the spinous processes of the cervical spine. They can form the basis of a new detailed differentiation of vertebrae and can represent an independent determinant of anatomical variability in the cervical spine.