Os ulnare externum
Os ulnare
externum als akzessorisches Ossikel der Handwurzel distal zwischen Triquetrum und Pisiforme. Die Untersuchung erfolgte zur Diagnostik der Fraktur des Processus styloideus radii.
Os ulnare externum
Akzessorische Handknochen Radiopaedia • CC-by-nc-sa 3.0 • de
Accessory ossicles of the wrist are commonly seen on plain radiographs of the wrist and associated cross-sectional imaging. Over 20 were originally described , although the more common include :
- lunula: between TFCC and triquetrum
- os styloideum (carpal boss): on dorsal surface of 2 or 3 metacarpal bases
- os triangulare: just distal to ulnar fovea
- trapezium secondarium: medial to tubercle of trapezium on volar surface
- os epilunate: dorsal to lunate
- os hamuli proprium: at tip of hamate hook
A handy mnemonic is LOTTEO.
The full list can be broadly split into three groups: those around the carpometacarpal joints, those around the scaphoid and those around the lunate.
The distal row, from ulnar margin to radial margin are:
- os vesalianum (hand)
- os ulnare externum
- os hamuli proprium
- secondary capitate
- gruber ossicle
- os styloideum
- secondary trapezoid
- trapezium secondarium
- os paratrapezium
The ossicles that surround the scaphoid (starting at the radioscaphoid joint and working anti-clockwise):
- paranavicular
- os radiostyloideum (persistent radial styloid)
- os radiale externum
- epitrapezium
- os centrale carpi
The ossicles that surround the lunate (starting at the scapholunate joint and working anti-clockwise):
- os hypolunatum
- os epilunatum
- os epipyramis
- accessory bone between lunate and triquetrum
- lunula
- os triangulare
- persistent ulnar styloid
- small bony element at the radioulnar joint
Siehe auch:
Assoziationen und Differentialdiagnosen zu 