Editing Triceratops (section)

===Postcranial skeleton===
[[File:Triceratops Raymond National Museum of Nature and Science.jpg|thumb|left|Specimen nicknamed "Raymond" that preserves the natural, non-pronated pose of the forelimb]]
Chasmosaurines showed little variation in their postcranial skeleton.<ref name="Dino2"/> The skeleton of ''Triceratops'' is markedly robust. Both ''Triceratops'' species possessed a very sturdy build, with strong limbs, short hands with three hooves each, and short feet with four hooves each.<ref name="fujiwara2009">{{Cite journal |last=Fujiwara |first=Shin-Ichi |date=December 12, 2009 |title=A reevaluation of the manus structure in ''Triceratops'' (Ceratopsia: Ceratopsidae) |journal=Journal of Vertebrate Paleontology |volume=29 |issue=4 |pages=1136–1147 |doi=10.1671/039.029.0406 |bibcode=2009JVPal..29.1136F |s2cid=86519018 |issn=0272-4634}}</ref> The [[vertebral column]] consisted of ten neck, twelve back, ten sacral, and about forty-five tail [[vertebra]]e. The front neck vertebrae were fused into a syncervical. Traditionally, this was assumed to have incorporated the first three vertebrae, thus implying that the frontmost [[atlas (anatomy)|atlas]] was very large and sported a neural spine. Later interpretations revived an old hypothesis by [[John Bell Hatcher]] that, at the very front, a vestige of the real atlas can be observed, the syncervical then consisting of four vertebrae. The vertebral count mentioned is adjusted to this view. In ''Triceratops'', the neural spines of the neck are constant in height and don't gradually slope upwards. Another peculiarity is that the neck ribs only begin to lengthen with the ninth cervical vertebra.<ref name="Dino2"/>

The rather short and high vertebrae of the back were, in its middle region, reinforced by ossified tendons running along the tops of the [[neural arch]]es. The straight sacrum was long and adult individuals show a fusion of all sacral vertebrae. In ''Triceratops'' the first four and last two sacrals had transverse processes, connecting the vertebral column to the pelvis, that were fused at their distal ends. Sacrals seven and eight had longer processes, causing the sacrum to have an oval profile in top view. On top of the sacrum, a neural plate was present formed by a fusion of the neural spines of the second through fifth vertebrae. ''Triceratops'' had a large pelvis with a long [[Ilium (bone)|ilium]]. The [[ischium]] was curved downwards. The foot was short with four functional toes. The phalangeal formula of the foot is 2-3-4-5-0.<ref name="Dino2"/>

[[File:Triceratops horridus.png|thumb|right|[[Life restoration]] of ''T. horridus'']]
Although certainly [[quadruped]]al, the posture of horned dinosaurs has long been the subject of some debate. Originally, it was believed that the front legs of the animal had to be [[Terrestrial locomotion#Posture|sprawling]] at a considerable angle from the [[thorax]] in order to better bear the weight of the head.<ref name="Dodhorned">{{Cite book |title=The Horned Dinosaurs |last=Dodson |first=P. |publisher=Princeton University Press |year=1996 |isbn=978-0-691-02882-8 |location=Princeton, New Jersey |url=https://archive.org/details/horneddinosaursn00dods_0 }}</ref> This stance can be seen in paintings by [[Charles R. Knight|Charles Knight]] and [[Rudolph F. Zallinger|Rudolph Zallinger]]. [[Ichnological]] evidence in the form of [[fossil trackway|trackways]] from horned dinosaurs and recent reconstructions of skeletons (both physical and digital) seem to show that ''Triceratops'' and other ceratopsids maintained an upright stance during normal locomotion, with the elbows flexed to behind and slightly bowed out, in an intermediate state between fully upright and fully sprawling, comparable to the modern rhinoceros.<ref name="fujiwara2009"/><ref name="CP01">{{cite journal | last1 = Christiansen | first1 = P. | last2 = Paul | first2 = G.S. | year = 2001 | title = Limb bone scaling, limb proportions, and bone strength in neoceratopsian dinosaurs | url = http://gspauldino.com/GaiaNeoceratopsian.pdf | journal = Gaia | volume = 16 | pages = 13–29 | access-date = October 29, 2012 | archive-date = August 19, 2018 | archive-url = https://web.archive.org/web/20180819045306/http://gspauldino.com/GaiaNeoceratopsian.pdf | url-status = live }}</ref><ref name="thompsonholmes2007">{{cite journal |last1=Thompson |first1=S. |last2=Holmes |first2=R. |year=2007 |title=Forelimb stance and step cycle in ''Chasmosaurus irvinensis'' (Dinosauria: Neoceratopsia) |journal=Palaeontologia Electronica |volume=10 |issue=1 |pages=17 p |url=http://palaeo-electronica.org/2007_1/step/index.html |access-date=November 20, 2010 |archive-date=December 11, 2018 |archive-url=https://web.archive.org/web/20181211003615/https://palaeo-electronica.org/2007_1/step/index.html |url-status=live }}</ref><ref name="regaetal2010">{{Cite book |title=New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium |last1=Rega |first1=E. |last2=Holmes |first2=R. |last3=Tirabasso |first3=A. |publisher=Indiana University Press |year=2010 |isbn=978-0-253-35358-0 |editor-last=Ryan |editor-first=Michael J. |location=Bloomington and Indianapolis |pages=340–354 |chapter=Habitual locomotor behavior inferred from manual pathology in two Late Cretaceous chasmosaurine ceratopsid dinosaurs, ''Chasmosaurus irvinensis'' (CMN 41357) and ''Chasmosaurus belli'' (ROM 843) |editor2-last=Chinnery-Allgeier |editor2-first=Brenda J. |editor3-last=Eberth |editor3-first=David A.}}</ref>

The hands and forearms of ''Triceratops'' retained a fairly primitive structure when compared to other quadrupedal dinosaurs, such as [[thyreophora]]ns and many [[sauropod]]s. In those two groups, the forelimbs of quadrupedal species were usually rotated so that the hands faced forward with palms backward ("pronated") as the animals walked. ''Triceratops'', like other ceratopsians and related quadrupedal [[ornithopod]]s (together forming the [[Cerapoda]]), walked with most of their fingers pointing out and away from the body, the original condition for dinosaurs. This was also retained by bipedal forms, like [[theropod]]s. In ''Triceratops'', the weight of the body was carried by only the first three fingers of the hand, while digits 4 and 5 were vestigial and lacked claws or hooves.<ref name="fujiwara2009"/> The phalangeal formula of the hand is 2-3-4-3-1, meaning that the first or innermost finger of the forelimb has two bones, the next has three, the next has four, etc.<ref>{{Cite book |title=Introduction to the study of dinosaurs |last=Martin |first=Anthony J. |date=2006 |publisher=Blackwell Pub |isbn=978-1405134132 |edition=2nd |location=Malden, MA |oclc=61130756}}</ref>