Fig. 5From: Clinical study of vacuum phenomenon in closed pelvic fractureDefinition and zoning of the distal and proximal sacroiliac joints. Each level of CT plain scan from the sacroiliac joint emergence to the sacral 3 foramina through five markers under the boundary was divided into four zones: sacroiliac joint emergence, the widest spacing between the sacral slope and the sacral nerve trunk canal, the disappearance of the lower boundary of the sacral 1 foramen, the disappearance of the lower boundary of the sacral 2 foramen, and the disappearance of the lower boundary of the sacral 3 foramen. The level between the beginning level of sacroiliac joint emergence and the maximum spacing between the sacral slope and the sacral nerve root canal was zone 1, etc., divided into four zonesBack to article page