Related Experiment Video
Updated: May 15, 2025

Isolation and Characterization of the Murine Uterosacral Ligaments and Pelvic Floor Organs
Published on: March 3, 2023
Anatomical variation of the sacroiliac joints - what the rheumatologist should know
Torsten Diekhoff1, Katharina Ziegeler2
1Department of Radiology, Immanuel Clinic Ruedersdorf, Brandenburg Medical School, Ruedersdorf bei Berlin, Germany.
Purpose Of Review:
Anatomical variations of the sacroiliac joints (SIJ) pose challenges in the diagnosis of axial spondyloarthritis (axSpA). Increased reliance on magnetic resonance imaging (MRI) for early detection has led to concerns about specificity, as anatomical variants can mimic inflammatory changes. This review highlights common SIJ variations and their implications for rheumatologists interpreting imaging findings.
Recent Findings:
Recent studies emphasize the high prevalence of SIJ anatomical variations, particularly in females, and their potential to influence imaging interpretation. Variations such as crescent-shaped ileum, intraarticular dysmorphisms, and accessory joint facets can lead to bone marrow edema and sclerosis, mimicking sacroiliitis. Additionally, lumbosacral transitional vertebrae alter SIJ biomechanics, potentially exacerbating symptoms in axSpA patients. Advances in MRI and computed tomography (CT) imaging protocols provide improved differentiation between anatomical variants and true inflammatory changes.
Summary:
Recognizing SIJ anatomical variations is crucial for avoiding misinterpretation of imaging findings and overdiagnosis of axSpA. MRI protocols incorporating additional imaging planes and CT correlation can enhance diagnostic accuracy. Awareness of these variations can refine patient management strategies, ensuring appropriate treatment for inflammatory and biomechanical SIJ pathologies.
Related Concept Videos
Functional Classification of Joints
The functional classification of joints is determined by the amount of mobility between the adjacent bones. Joints are functionally classified as a synarthrosis or immobile joint, an amphiarthrosis or slightly moveable joint, or as a diarthrosis, a freely moveable joint. Fibrous and cartilaginous joints can be functionally classified as either synarthroses or amphiarthroses, whereas all synovial joints are classified as diarthroses.
Synarthrosis
An...
Articulations of the Vertebral Column
Abdominal Regions and Quadrants
The simpler quadrants approach, which is more commonly used in medicine, subdivides the cavity with one horizontal and one vertical line that intersects at the patient's umbilicus (navel). The four...
Structural Joints: Synovial Joints
Introduction to Joints
Structural Joints: Cartilaginous Joints
There are two types of cartilaginous joints:
Synchondrosis
A synchondrosis ("joined by cartilage") is a cartilaginous joint where bones are connected by hyaline cartilage. Synchondrosis may be temporary...

