Magnetic Resonance Imaging Evaluation of Coccygeal Morphology in Coccydynia

Aim: Coccydynia is a multifactorial clinical condition characterized by coccygeal pain that adversely affects daily activities. This study aimed to evaluate coccygeal morphometric parameters using magnetic resonance imaging (MRI) in patients with coccydynia and to investigate the relationship between coccygeal morphology and coccydynia.Materials and Methods: This retrospective, single-center study included 100 adults who underwent pelvic or lower abdominal MRI between January 2022 and August 2025. Fifty patients with clinically confirmed coccydynia were compared with 50 asymptomatic controls. Coccygeal morphology and measurements, including sacrococcygeal angle, intercoccygeal angle, coccyx length, lateral deviation, coccygeal segment number, distal spicule presence, and Postacchini–Massobrio morphological type, were assessed on MRI. Group comparisons were performed using appropriate statistical tests, and univariate and multivariate logistic regression analyses were conducted to identify factors independently associated with coccydynia.Results: The ICA was significantly smaller in the coccydynia group than in controls (141.82° ± 14.6 vs. 148.50° ± 14.1, p = 0.022), while coccyx length was greater (34.86 ± 6.6 mm vs. 31.98 ± 6.5 mm, p = 0.032). Distal coccygeal spicules were more frequent in patients with coccydynia (18% vs. 2%, p = 0.008), as was lateral deviation (24% vs. 6%, p = 0.012). Type II-IV morphologies were significantly more prevalent in the coccydynia group (78% vs. 44%, p < 0.001). Multivariate analysis identified a reduced ICA (OR = 0.956), distal spicule presence (OR = 19.36), and Type III-IV morphology as independent predictors of coccydynia (p < 0.05). Males had longer coccyges than females (p < 0.001).Conclusions: MRI demonstrates distinct coccygeal morphological features associated with coccydynia and provides a comprehensive, radiation-free assessment that may support imaging-based risk stratification.