Figure 1

(A) Search strategy for articles and (B) Funnel plots to determine if there was publication bias. Funnel plot 1: Graph of sample size of individual study (x-axis) and its respective prevalence of anterior atlanto-axial subluxations (y-axis). Funnel plot 2: Graph of sample size of individual study (x-axis) and its respective prevalence of rheumatoid arthritis (RA)-related cervical changes (y-axis). Funnel plot 3: Graph of sample size of individual study (x-axis) and its respective prevalence of vertical atlanto-axial subluxations (y-axis). Funnel plot 4: Graph of sample size of individual study (x-axis) and its respective prevalence of subaxial subluxations (y-axis). Funnel plot 5: Graph of sample size of individual study (x-axis) and its respective prevalence of cervical myelopathy (y-axis).