Editing Phalanx bone (section)

====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>