Persistent ulnar styloid ossicle
A persistent ulnar styloid ossicle is an anatomical variant where the ulna styloid ossification center fails to unite with the ulna.
Seen as a well-corticated ossification just adjacent to the ulnar styloid.
- os triangulare: a small accessory ossicle located between the ulnar styloid, lunate and triquetrum
- ununited old ulnar styloid fracture