The Craniocervical junction is a complex region where the skull and upper cervical spine connect. The connection between the brain and the spinal cord is at the base of the brainstem in the region of the Craniocervical junction. The base of the skull forms joints with the Atlas and the Axis at the Occipital-C1 articulation & the C1-C2 articulation.
This is a complex region where the skull and upper cervical spine connect. The connection between the brain and the spinal cord is at the base of the brainstem in the region of the Craniocervical junction. The base of the skull forms joints with the Atlas and the Axis at the Occipital-C1 articulation & the C1-C2 articulation.
The vertebral arteries take a complex course at the Craniocervical junction where they course laterally though the Second cervical vertebral body (also called the Axis) and then pass through the transverse foramina of the Atlas (First cervical vertebral body) which are widely spaced. The Vertebral arteries then course posteriorly then medially over the lateral edges of the C1 (Atlas, First cervical vertebral body) and pass through the dura mater into the subarachnoid space.
Data suggest that there are sex-specific differences with respect to measurements at the CCJ between men and women, with women showing a more posteriorly inclined odontoid process. There were also differences between the CM-I and control groups: a more acute clivus-canal angle was associated with CM-I in the adult population. These CCJ findings could have an influence on pre surgical planning 7).
Endoscopic approaches to the anterior craniocervical junction are increasing in frequency. Choice of oral versus endoscopic endonasal approach to the odontoid often depends on the relationship of the C1-2 complex to the hard palate. However, it is not known how this relevant anatomy changes with age.
Mallory et al hypothesize that there is a dynamic relationship of C-2 and the hard palate, which changes with age, and potentially affects the choice of surgical approach. The aim of this study was to characterize the relationship of C-2 relative to the hard palate with respect to age and sex.
Emergency department billing and trauma records from 2008 to 2014 were reviewed for patients of all ages who underwent cervical or maxillofacial CT as part of a trauma evaluation for closed traumatic brain injury. Patients who had a CT scan that allowed adequate visualization of the hard palate, opisthion, and upper cervical spine (C-1 and C-2) were included. Patients who had cervical or displaced facial/skull base fractures, a history of rheumatoid arthritis, or craniofacial anomalies were excluded. The distance from McGregor's line to the midpoint of the inferior endplate of C-2 (McL-C2) was measured on midsagittal CT scans. Patients were grouped by decile of age and by sex. A 1-way ANOVA was performed with each respective grouping.
Ultimately, 483 patients (29% female) were included. The mean age was 46 ± 24 years. The majority of patients studied were in the 2nd through 8th decades of life (85%). Significant variation was found between McL-C2 and decile of age (p < 0.001) and sex (p < 0.001). The mean McL-C2 was 27 mm in the 1st decade of life compared with the population mean of 37 mm. The mean McL-C2 was also noted to be smaller in females (mean difference 4.8 mm, p < 0.0001). Both decile of age (p = 0.0009) and sex (p < 0.0001) were independently correlated with McL-C2 on multivariate analysis.
The relationship of C-2 and the hard palate significantly varies with respect to age and sex, descending relative to the hard palate a full centimeter on average in adulthood. These findings may have relevance in determining optimal surgical approaches for addressing pathology involving the anterior craniocervical junction 8).