Editing Phalanx bone (section)

===Other animals===
Most land [[mammal]]s including humans have a 2-3-3-3-3 formula in both the [[hand]]s (or [[paw]]s) and [[Foot|feet]]. Primitive [[reptile]]s usually had the formula 2-3-4-4-5, and this pattern, with some modification, remained in many later reptiles and in the [[mammal-like reptile]]s. The phalangeal formula in the [[Flipper (anatomy)|flippers]] of [[cetaceans]] (marine mammals) varies widely due to hyperphalangy (the increase in number of [[phalanx bones]] in the digits). In [[humpback whales]], for example, the phalangeal formula is 0/2/7/7/3; in [[pilot whales]] the formula is 1/10/7/2/1.<ref>Cooper et al, [https://www.researchgate.net/publication/320639177_Review_and_experimental_evaluation_of_the_embryonic_development_and_evolutionary_history_of_flipper_development_and_hyperphalangy_in_dolphins_Cetacea_Mammalia "Review and experimental evaluation of the embryonic development and evolutionary history of flipper development and hyperphalangy in dolphins (Cetacea: Mammalia)"], ''ResearchGate'', doi: 10.1002/dvg.23076. October 2017</ref>

In vertebrates, proximal phalanges have a similar placement in the corresponding limbs, be they [[paw]], [[wing]] or [[fin]]. In many species, they are the longest and thickest phalanx ("finger" bone). The middle phalanx also has a corresponding place in their limbs, whether they be [[paw]], [[wing]], [[hoof]] or [[fin]].

The distal phalanges are cone-shaped in most mammals, including most primates, but relatively wide and flat in humans.

====Primates====
[[File:Distal-phalanges-comparison-Journal.pone.0011727.g002.png|thumb|Morphological comparisons of pollical distal phalanges in African apes, extant humans and selected hominins. Although with several morphological differences, all the features related to refined manipulation in modern humans are already present in the late Miocene [[Orrorin]].<ref name="PLOS-2010" />]]
The morphology of the distal phalanges of human thumbs closely reflects an adaptation for a refined precision grip with pad-to-pad contact. This has traditionally been associated with the advent of stone tool-making. However, the intrinsic hand proportions of [[Australopithecus|australopiths]] and the resemblance between human hands and the short hands of [[Miocene]] apes, suggest that human hand proportions are largely [[plesiomorphic]] (as found in ancestral species)&nbsp;— in contrast to the derived elongated hand pattern and poorly developed thumb musculature of other extant [[hominoid]]s.<ref name="PLOS-2010" /><!-- Abstract and Introduction -->

In [[Neanderthal]]s, the apical tufts were expanded and more robust than in modern and early [[Upper Paleolithic]] humans. A proposal that Neanderthal distal phalanges was an adaptation to colder climate (than in Africa) is not supported by a recent comparison showing that in [[hominin]]s, cold-adapted populations possessed smaller apical tufts than do warm-adapted populations.
<ref name="Mittra">{{cite journal |last1=Mittra |first1=ES |last2=Smith |first2=HF |last3=Lemelin |first3=P |last4=Jungers |first4=WL |date=Dec 2007 |title=Comparative morphometrics of the primate apical tuft. |journal=American Journal of Physical Anthropology |pmid=17657781 |doi=10.1002/ajpa.20687 |volume=134 |issue=4 |pages=449–59}}</ref>

In non-human, living primates the apical tufts vary in size, but they are never larger than in humans. Enlarged apical tufts, to the extent they actually reflect expanded digital pulps, may have played a significant role in enhancing friction between the hand and held objects during [[Neolithic]] toolmaking.<ref name="CARTA" />

Among non-human primates [[phylogenesis]] and style of locomotion appear to play a role in apical tuft size. Suspensory primates and [[New World monkey]]s have the smallest apical tufts, while terrestrial quadrupeds and [[Strepsirrhini|Strepsirrhines]] have the largest.<ref name="Mittra" />
A study of the fingertip morphology of four small-bodied New World monkey species, indicated a correlation between increasing small-branch foraging and reduced flexor and extensor tubercles in distal phalanges and broadened distal parts of distal phalanges, coupled with expanded apical pads and developed epidermal ridges. This suggests that widened distal phalanges were developed in arboreal primates, rather than in quadrupedal terrestrial primates.<ref>{{cite journal |last=Hamrick |first=MW |date=Jun 1998 |title=Functional and adaptive significance of primate pads and claws: evidence from New World anthropoids |journal=American Journal of Physical Anthropology |pmid=9637179 |doi=10.1002/(SICI)1096-8644(199806)106:2<113::AID-AJPA2>3.0.CO;2-R |volume=106 |issue=2 |pages=113–27}}</ref>

==== Cetaceans ====
Whales exhibit hyperphalangy. Hyperphalangy is an increase in the number of phalanges beyond the [[Plesiomorphy and symplesiomorphy|plesiomorphic]] mammal condition of three phalanges-per-digit.<ref name=":5">{{Cite journal|last1=Cooper|first1=Lisa|last2=Sears|first2=Karen|last3=Armfield|first3=Brooke|last4=Kala|first4=Bhavneet|last5=Hubler|first5=Merla|last6=Thewissen|first6=J G M|date=2017-10-01|title=Review and experimental evaluation of the embryonic development and evolutionary history of flipper development and hyperphalangy in dolphins (Cetacea: Mammalia)|url=https://www.researchgate.net/publication/320639177|journal=Genesis|volume=56|issue=1|pages=e23076|doi=10.1002/dvg.23076|pmid=29068152|doi-access=free}}</ref> Hyperphalangy was present among extinct [[Marine reptile|marine reptiles]] -- [[Ichthyosaur|ichthyosaurs]], [[Plesiosauria|plesiosaurs]], and [[Mosasaur|mosasaurs]] -- but not other marine mammals, leaving whales as the only [[Marine mammal|marine mammals]] to develop this characteristic.<ref>{{Cite journal|last1=Fedak|first1=Tim J|last2=Hall|first2=Brian K|date=2004|title=Perspectives on hyperphalangy: patterns and processes|journal=Journal of Anatomy|volume=204|issue=3|pages=151–163|doi=10.1111/j.0021-8782.2004.00278.x|issn=0021-8782|pmc=1571266|pmid=15032905}}</ref> The evolutionary process continued over time, and a very derived form of hyperphalangy, with six or more phalanges per digit, evolved convergently in [[Rorqual|rorqual whales]] and [[Oceanic dolphin|oceanic dolphins]], and was likely associated with another wave of signaling within the interdigital tissues.<ref name=":52">{{Cite journal|last1=Cooper|first1=Lisa|last2=Sears|first2=Karen|last3=Armfield|first3=Brooke|last4=Kala|first4=Bhavneet|last5=Hubler|first5=Merla|last6=Thewissen|first6=J G M|date=2017-10-01|title=Review and experimental evaluation of the embryonic development and evolutionary history of flipper development and hyperphalangy in dolphins (Cetacea: Mammalia)|url=https://www.researchgate.net/publication/320639177|journal=Genesis|volume=56|issue=1|pages=e23076|doi=10.1002/dvg.23076|pmid=29068152|doi-access=free}}</ref>

====Other mammals====
{{image frame|content={{Gallery|mode=packed|width=150|height=150
 |File:Handskelett MK1888.png|Comparison of the phalanges of an orangutan, dog, pig, cow, tapir and horse
 |File:Masai Giraffe right-rear foot.jpg|Distal phalanges of a [[Masai giraffe]]
}}

{{Gallery|mode=packed|width=150|height=150
 |File:MC Drei-Finger-Faultier.jpg|Three-fingered sloth
 |File:Scelidotherium right hand.JPG|Terminal phalanx of a ''[[Scelidotherium]]'' [[ground sloth]]
}}}}
In [[ungulate]]s (hoofed mammals) the forelimb is optimized for speed and endurance by a combination of length of stride and rapid step; the proximal forelimb segments are short with large muscles, while the distal segments are elongated with less musculature. In two of the major groups of ungulates, [[Odd-toed ungulate|odd-toed]] and [[Even-toed ungulate|even-toed]] ungulates, what remain of the "hands"&nbsp;— the [[Metacarpus|metacarpal]] and phalangeal bones&nbsp;— are elongated to the extent that they serve little use beyond locomotion. The [[giraffe]], the largest even-toed ungulate, has large terminal phalanges and fused metacarpal bones able to absorb the stress from running.<ref name="Gough-Palmer">{{cite journal |last1=Gough-Palmer |first1=Antony L. |last2=Maclachlan |first2=Jody |last3=Routh |first3=Andrew |date=March 2008 |title=Paws for Thought: Comparative Radiologic Anatomy of the Mammalian Forelimb |journal=RadioGraphics  |doi=10.1148/rg.282075061 |pmid=18349453 |volume=28 |issue=2 |pages=501–510}}</ref>

The [[sloth]] spends its life hanging upside-down from branches, and has highly specialized third and fourth digits for the purpose. They have short and squat proximal phalanges with much longer terminal phalanges. They have [[vestigial]] second and fifth metacarpals, and their palm extends to the distal [[interphalangeal articulations of hand|interphalangeal joints]]. The arboreal specialization of these terminal phalanges makes it impossible for the sloth to walk on the ground where the animal has to drag its body with its claws.<ref name="Gough-Palmer" />