Table 4 Bilateral existence and coexistence of multiple variants within one SIJ, analyzed for 430 SIJ
From: Anatomical variation of the sacroiliac joints: an MRI study with synthetic CT images
Total incidence (n = 430) | Bilateral presence | Not in combination with another variant in one SIJ | Combination with at least one other variant within the same SIJ | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Bipartite iliac bony plate | Accessory joint | Iliosacral complex | Semicircular defect | Crescent iliac bony plate | Isolated synostosis | Unfused ossification center | Dysmorphic posterior part | Extra SIJ facet superiorly | ||||
No variant | 74 | 78.4% (58/74) | ||||||||||
Bipartite iliac bony plate | 117 | 87.2% (102/117) | 28.2% (33/117) | – | 18.8% (22/117) | 13.7% (16/117) | 10.3% (12/117) | 33.3% (39/117) | 0.9% (1/117) | 0.9% (1/117) | 18.8% (22/117) | 0 |
Accessory joint | 56 | 75.0% (42/56) | 30.4% (17/56) | 39.3% (22/56) | – | 8.9% (5/56) | 1.8% (1/56) | 26.8% (15/56) | 5.4% (3/56) | 0 | 14.3% (8/56) | 0 |
Iliosacral complex | 119 | 97.5% (116/119) | 67.2% (80/119) | 13.4% (16/119) | 4.2% (5/119) | – | 0 | 5% (6/119) | 2.5% (3/119) | 0 | 15.1% (18/119) | 0 |
Semicircular defect | 34 | 88.2% (30/34) | 50% (17/34) | 35.3% (12/34) | 2.9% (1/34) | 0 | – | 20.6% (7/34) | 0 | 0 | 8.8% (3/34) | 0 |
Crescent iliac bony plate | 116 | 96.6% (112/116) | 46.6% (54/116) | 33.6% (39/116) | 12.9% (15/116) | 5.2% (6/116) | 6% (7/116) | – | 2.6% (3/116) | 0 | 12.1% (14/116) | 0 |
Isolated synostosis | 9 | 66.7% (6/9) | 0 | 11.1% (1/9) | 33.3% (3/9) | 33.3% (3/9) | 0 | 33.3% (3/9) | – | 0 | 0 | 0 |
Unfused ossification center | 3 | 66.7% (2/3) | 66.7% (2/3) | 33.3% (1/3) | 0 | 0 | 0 | 0 | 0 | – | 0 | 0 |
Dysmorphic posterior part | 65 | 89.2% (58/65) | 29.2% (19/65) | 33.8% (22/65) | 12.3% (8/65) | 27.7% (18/65) | 4.6% (3/65) | 21.5% (14/65) | 0 | 0 | – | 0 |
Extra SIJ facet superiorly | 2 | 100.0% (2/2) | 100% (2/2) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | – |