Table 2 Frequencies of SIJ variants according to sex, age and BMI
From: Anatomical variation of the sacroiliac joints: an MRI study with synthetic CT images
Total study group | Sex | Age (years) | BMI (kg/m2)* | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Male | Female | 18–20 | 21–30 | 31–40 | 41–50 | 51–60 | 61–70 | 71–80 | < 18.5 | 18.5–24.9 | 25–29.9 | ≥ 30 | ||
Total number of joints | 430 | 162 | 268 | 22 | 104 | 140 | 112 | 44 | 6 | 2 | 12 | 222 | 128 | 68 |
No variant | 74 (17.2%) | 36 (22.2%) | 38 (14.2%) | 3 (13.6%) | 20 (19.2%) | 26 (18.6%) | 19 (17%) | 4 (9.1%) | 2 (33.3%) | 0 | 2 (16.7%) | 42 (18.9%) | 21 (16.4%) | 9 (13.2%) |
Bipartite iliac bony plate | 117 (27.2%) | 13 (8%) | 104 (38.8%) | 6 (27.3%) | 26 (25%) | 47 (33.6%) | 25 (22.3%) | 11 (25%) | 2 (33.3%) | 0 | 5 (41.7%) | 63 (28.4%) | 33 (25.8%) | 16 (23.5%) |
Accessory joint | 56 (13%) | 14 (8.6%) | 42 (15.7%) | 1 (4.5%) | 11 (10.6%) | 26 (18.6%) | 10 (8.9%) | 4 (9.1%) | 2 (33.3%) | 2 (100%) | 2 (16.7%) | 22 (9.9%) | 24 (18.8%) | 8 (11.8%) |
Iliosacral complex | 119 (27.7%) | 64 (39.5%) | 55 (20.5%) | 2 (9.1%) | 35 (33.7%) | 28 (20%) | 32 (28.6%) | 22 (50%) | 0 | 0 | 4 (33.3%) | 47 (21.2%) | 40 (31.3%) | 28 (41.2%) |
Semicircular defect | 34 (7.9%) | 10 (6.2%) | 24 (9%) | 4 (18.2%) | 7 (6.7%) | 18 (12.9%) | 5 (4.5%) | 0 | 0 | 0 | 0 | 19 (8.6%) | 7 (5.5%) | 8 (11.8%) |
Crescent iliac bony plate | 116 (27%) | 39 (24.1%) | 77 (28.7%) | 10 (45.5%) | 24 (23.1%) | 43 (30.7%) | 27 (24.1%) | 10 (22.7%) | 2 (33.3%) | 0 | 6 (50%) | 69 (31.1%) | 31 (24.2%) | 10 (14.7%) |
Isolated synostosis | 9 (2.1%) | 6 (3.7%) | 3 (1.1%) | 0 | 0 | 1 (0.7%) | 5 (4.5%) | 1 (2.3%) | 0 | 2 (100%) | 0 | 6 (2.7%) | 3 (2.3%) | 0 |
Unfused ossification center | 3 (0.7%) | 2 (1.2%) | 1 (0.4%) | 0 | 2 (1.9%) | 1 (0.7%) | 0 | 0 | 0 | 0 | 0 | 1 (0.5%) | 2 (1.6%) | 0 |
Dysmorphic posterior part | 65 (15.1%) | 9 (5.6%) | 56 (20.9%) | 2 (9.1%) | 10 (9.6%) | 21 (15%) | 29 (25.9%) | 3 (6.8%) | 0 | 0 | 4 (33.3%) | 30 (13.5%) | 21 (16.4%) | 10 (14.7%) |
Extra SIJ facet superiorly | 2 (0.5%) | 0 | 2 (0.7%) | 0 | 2 (1.9%) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 2 (2.9%) |