Aim:This study aimed to assess the craniocervical junction (CCJ) by using radiological measurements in patients with Adolescent Idiopathic Scoliosis (AIS) and Scheuermann’s Kyphosis (SK) compared to normal adolescent population.Material and Methods:Patients were assigned to three groups. Group 1 consisted of AIS patients, Group 2 consisted of patients with SK, and Group 3 was the control group who had no spinal disorder. The groups were matched based on age and gender. Major Cobb angle and kyphosis angle were measured on X-Ray. Basion-axial interval (BAI), basion-dens interval (BDI), posterior atlantodental interval (PADI), anterior atlantodental interval (ADI), atlanto-occipital interval (AOI), and Power\'s ratio were measured by computer tomography. The results were compared in each group statistically. Results:A total of 120 participants, comprised of 78 (65%) female and 42 (35%) male were included in the study. There was no statistically difference between 3 groups based on age and gender (p>0.05). According to the measurements, Group 3 had significantly higher PADI measurements than Group 1 (p=0.01). The ADI measurements of Group 2 were significantly higher than those of Group 1 and Group 3 (p=0.01). Group 3 had significantly higher BDI measurements than Group 1 and Group 2. (p=0.01). The Power ratios of Group 1 and Group 3 were statistically higher than that of Group 2 (p=0.01). There were no statistically significant differences between the groups in terms of AOI and BAI measurements (p=0.84, p=0.18, respectively).Conclusion:The presence of AIS and Scheuermann’s kyphosis may affect the measurement of CCJ and it may be considered to evaluate instability of the region.