Rümeysa Üzümcüoglu; Hidir Pekmez; Gökçe Bagci Uzun; Ipek Balikci Cicek; Zeynep Kaya &Muhammed Furkan Arpaci

Ankylosing spondylitis (AS) is a chronic inflammatory disease that primarily affects the sacroiliac joints and axial skeleton. This study investigated the relationship between sacral morphometry and sacroiliac joint cross-sectional area in patients with AS using magnetic resonance imaging (MRI). A retrospective morphometric analysis was performed on MRI scans from 160 individuals, including 80 patients with AS (40 women and 40 men) and 80 age- and sex-matched healthy controls. Multiple sacral morphometric parameters were measured in the sagittal, axial, and coronal planes, together with the bilateral sacroiliac joint cross-sectional areas. Male patients exhibited significantly greater sacral dimensions than female patients for several morphometric parameters. Compared with controls, both male and female patients with AS demonstrated significantly higher sacral slope values and markedly reduced bilateral sacroiliac joint cross-sectional areas (p<0.001). Significant correlations were identified between sacroiliac joint area and several sacral morphometric measurements, including posterior sacral length, sacral area, posterior sacral curvature length, intercornual distance, and sacral slope. These findings indicate that AS is associated with significant alterations in sacral morphology and substantial narrowing of the sacroiliac joint. MRI-based morphometric assessment may provide valuable complementary information for the structural evaluation of patients with AS and contribute to a better understanding of disease-related anatomical changes.

KEY WORDS: Ankylosing spondylitis; Sacrum; Sacroiliac joint; Magnetic resonance imaging; Morphometry.

ÜZÜMCÜOGLU, R.; PEKMEZ, H.; UZUN, G. B.; BALIKCI CICEK, I.; KAYA, Z. & ARPACI, M. F. Investigation of the relationship of the sacroiliac joint with the sacrum in patients with ankylosing spondylitis. Int. J. Morphol., 44(3):984-993, 2026.