Two images demonstrate five fat planes on the PA wrist radiograph, and four fat planes on the lateral wrist radiograph that should be scrutinized on any wrist radiography interpretation.
- Soft tissue swelling is almost always seen in one or more compartments in cases of acute fracture or dislocation
- When swelling is observed on a trauma wrist radiograph, all soft tissue areas should be examined thoroughly and the assumption is that they may be a fracture or dislocation associated with swelling
- Abnormal fat planes = fat plane is convex out of the underlying bone, or loss of its distinct plane
What Do They Suggest?
- Dorsal hand swelling -> 2nd through 5th metacarpal injury
- Dorsal wrist swelling -> carpal fractures or wrist dislocation
- Dorsal radial swelling -> forearm fractures
- Pronator fat pad swelling -> forearm fractures
- Thenar swelling -> thumb fractures
- Hypothenar swelling -> 2nd through 5th metacarpal injury
- Scaphoid swelling -> carpal fractures
- Pararadial swelling -> forearm injury
- Paraulnar swelling -> forearm fracture
Curtis DJ, Downey, Jr., EF, Brower AC, et al. Importance of soft-tissue evaluation in hand and wrist trauma: statistical evaluation. AJR 1984; 142:781-788.