CT Measurements of the Upper Cervical Spine in Normal Chinese Pediatric Patients Aged 4–15

<title>Abstract</title> <p>Background context: Upper cervical spine parameters and developmental trajectories in normal Chinese pediatric patients are inconsistently reported. Purpose To determine normal values and age- or sex-related differences in the upper cervical spine (ages 4–15). Design: A retrospective cohort study. Patient sample: 212 normal Chinese pediatric outpatients (137 males, 75 females) aged 4–15 years without cervical spine pathology. Outcome measures: Eleven CT anatomical parameters of the upper cervical spine, including C1/C2 vertebral bodies, C2 pedicles, neural canal, and associated angles. Methods Multiplanar reconstructions of cervical CT scans (bone window) were used. Regression models evaluated developmental trajectories and growth inflection points; ANCOVA assessed gender differences. Results Mean Atlantodental Interval (ADI) was 2.41 ± 0.60 mm; C1 Space Available for the Cord (C1 SAC), 17.99 ± 1.85 mm; C2 Sagittal Canal Diameter (C2 SCD), 15.75 ± 1.20 mm; C2 Pedicle Width (C2 PW), 5.91 ± 0.78 mm. C1 SAC, C2 SCD, and basal angle were stable across age groups (p &gt; 0.05), while ADI and other bony parameters significantly changed (p &lt; 0.05). C1 Lateral Mass Height (C1 LMH) alone showed non-linear growth, with a decreasing growth slope after an 11.3-year inflection point. Only C1 SAC showed gender differences in 4–7, whereas C1 SAC, C1 Lateral Mass Width (C1 LMW), C2 SCD, C2 Pedicle Height (C2 PH), and Basal Angle showed such differences in 13–15. Conclusions This study established a normative Chinese pediatric upper cervical CT database. Neural canal dimensions mature early and remain stable, while most osseous parameters grow linearly except C1 LMH. Females exhibit smaller dimensions, emphasising the importance of sex-specific preoperative planning.</p>