Os centrale carpi
The os centrale carpi is an accessory ossicle of the wrist positioned dorsally between the scaphoid, the trapezoid and the capitate bones . As with most other accessory ossicles of the wrist, the os centrale carpi is a rare finding on imaging and is, in the majority of cases, an asymptomatic anatomic variant.
It has an incidence of 0.3-1.6% .
It is thought to represent a separate ossification center that is seen in the embryo at 6 weeks, that then normally fuses with the distal ulnar portion of the scaphoid at 8 weeks .
Os centrale carpi have been observed to cause symptoms such as intermittent pain, clicking and crepitus due to its mobility in the carpus. Osteonecrosis of the os centrale carpi has been reported after trauma .