Os trapezium secundarium

The trapezium secondarium (or trapezium secundarium or secondary trapezium) is an accessory ossicle of the wrist. It can be seen adjacent to the tubercle of the trapezium superomedially .


According to Pfitzner, the trapezium secondarium is one of four potential secondary ossification centers lying around the primary ossification center of the trapezium that may remain as separated bones. The other sites include the epitrapezium adjacent to the scaphoid, the paratrapezium most lateral and the praetrapezium lying on the palmar surface of the trapezium .

Radiographic features

It may be visualized sitting between the 1 and 2bases of each respective metacarpal bone on lateral and oblique hand radiographs .