Editing Carpal bones (section)

== Other animals==
{{See also|Carpus and tarsus of land vertebrates}}
The structure of the carpus varies widely between different groups of [[tetrapod]]s, even among those that retain the full set of five digits. In primitive fossil [[amphibian]]s, such as ''[[Eryops]]'', the carpus consists of three rows of bones; a proximal row of three carpals, a second row of four bones, and a distal row of five bones. The proximal carpals are referred to as the '''radiale''', '''intermedium''', and '''ulnare''', after their proximal articulations, and are [[homology (biology)|homologous]] with the scaphoid, lunate, and triquetral bones respectively. The remaining bones are simply numbered, as the first to fourth '''centralia''' (singular: '''centrale'''), and the first to fifth '''distal carpals'''. Primitively, each of the distal bones appears to have articulated with a single metacarpal.

However, the vast majority of later [[vertebrate]]s, including modern [[amphibian]]s, have undergone varying degrees of loss and fusion of these primitive bones, resulting in a smaller number of carpals. Almost all [[mammal]]s and [[reptile]]s, for example, have lost the fifth distal carpal, and have only a single centrale - and even this is missing in humans. The pisiform bone is somewhat unusual, in that it first appears in primitive reptiles, and is never found in amphibians.

Because many tetrapods have fewer than five digits on the forelimb, even greater degrees of fusion are common, and a huge array of different possible combinations are found. The wing of a modern [[bird]], for example, has only two remaining carpals; the radiale (the scaphoid of mammals) and a bone formed from the fusion of four of the distal carpals.<ref name=VB>{{cite book |author=Romer, Alfred Sherwood|author2=Parsons, Thomas S.|year=1977 |title=The Vertebrate Body |publisher=Holt-Saunders International |location= Philadelphia, PA|pages= 200–202|isbn= 0-03-910284-X}}</ref>

The carpus and tarsus are both described as podial elements or (clusters of) podial bones.<ref>{{Cite journal|last1=Galateanu|first1=Gabriela|last2=Hildebrandt|first2=Thomas B.|last3=Maillot|first3=Alexis|last4=Etienne|first4=Pascal|last5=Potier|first5=Romain|last6=Mulot|first6=Baptiste|last7=Saragusty|first7=Joseph|last8=Hermes|first8=Robert|date=2013-07-09|title=One Small Step for Rhinos, One Giant Leap for Wildlife Management- Imaging Diagnosis of Bone Pathology in Distal Limb|journal=PLOS ONE|language=en|volume=8|issue=7|pages=e68493|doi=10.1371/journal.pone.0068493|issn=1932-6203|pmc=3706412|pmid=23874643|bibcode=2013PLoSO...868493G|doi-access=free}}</ref>

In some [[Macropodidae|macropod]]s, the scaphoid and lunar bones are fused into the scapholunar bone.<ref>[http://home.brisnet.org.au/~mccready/Swamp%20Wallaby.htm Swamp Wallaby (''Wallabia bicolor'') carpals<!-- Bot generated title -->] {{webarchive|url=https://web.archive.org/web/20070930015714/http://home.brisnet.org.au/~mccready/Swamp%20Wallaby.htm |date=2007-09-30 }}</ref>

In [[crustacean]]s, "carpus" is the scientific term for the claws or "pincers" present on some legs. (See [[Decapod anatomy]])