An accessory bone or supernumerary bone is a bone that is not normally present in the body, but can be found as a variant in a significant number of people. It poses a risk of being misdiagnosed as bone fractures on radiography. Wrist and hand
Os ulnostyloideum
The os ulnostyloideum is an ulnar styloid process that is not fused to the rest of the ulna bone. On X-rays, an os ulnostyloideum is sometimes mistaken for an avulsion fracture of the styloid process. However, the distinction between these is extremely difficult. It is alleged that the os ulnostyloideum has a close relationship with or is synonymous with the os triquetrum secundarium. Os centrale
The os carpi centrale (also briefly os centrale) is, where present, located on the dorsal side of the wrist between the scaphoid, the trapezoid and capitate, radially to the deep fossa of the capitate. The bone is present in almost every human embryo of 17–49 mm length, but then usually fuses with the ulnar side of the scaphoid. Sometimes it fuses with the capitate or the trapezoid. The literature also refers to an os centrale at the palm of the carpus, but this existence is questioned.In most primates, including orangutans and gibbons, the os centrale is an independent bone that is attached to the scaphoid by strong ligaments. Conversely, in African apes and humans, the os centrale normally fuses to the scaphoid early in development.
Australia
As of January 2011, the Australian motor vehicle fleet had 16.4 million registered vehicles, with an ownership rate of 730 motor vehicles per 1000 people, up from 696 vehicles per 1000 residents in 2006. The motor vehicle fleet grew 14.5% since 2006, for an annual rate of 2.7% during this five-year period. Comparison by regions
The following table compares vehicle ownership rates by region with the US, the country with the highest motorization rate in the world, and how it has evolved from 1999 to 2016. Production by country
In 2017, a total of 97.3 million cars and commercial vehicles were built worldwide, led by China, with about 29 million motor vehicles manufactured, followed by the United States with 11.2 million, and Japan with 9.7 million. The following table shows the top 15 manufacturing countries for 2017 and their corresponding annual production between 2004 and 2017. See also
References


== External links ==